It has been reported that oral health is closely related to overall health, and dental health management can be considered an integral part of general health management. Oral biofilm is widely recognized as a key factor in the etiology of periodontal disease. The primary goal in preventing periodontal disease is to inhibit the formation and reformation of oral biofilms, which necessitates the development of highly effective biofilm inhibiting materials. Therefore, we developed IPMP (isopropylmethylphenol) loaded PLGA (polylactic acid-co-glycolic acid) nanoparticles (NP) with high permeability to biofilms, aimed at effectively preventing periodontal disease.

 Active ingredient-loaded PLGA NP are thought to be capable of delivering drugs deeper into biofilms compared to the active ingredient alone. IPMP not only has a strong antibacterial effect but is also less irritating and highly safe and widely used in cosmetics and other products, including toothpaste. We developed three prototypes of toothpaste: one that did not contain either IPMP or PLGA NP, one that contained IPMP, and one that contained the IPMP-loaded PLGA NP, and conducted clinical trials. The increase in oral bacterial counts was suppressed in the IPMP-loaded PLGA NP group compared with the IPMP-only group. The amount of hemoglobin in the saliva tended to be lower in the IPMP-loaded PLGA NP group than in the IPMP-only group. The sulfur compound concentration tended to be lower in the IPMP-loaded PLGA NP group than in the IPMP-only group. When PLGA NP containing the fluorescent component Coumarin were used, the fluorescent component remained on the tongue even after rinsing.

 Clinical trials using IPMP-loaded PLGA NP demonstrated reductions in bacterial counts, subgingival bleeding, and improved halitosis. These results suggest that IPMP-loaded PLGA NP are effective in inhibiting biofilm formation.

Background and Aims: Powder technology plays a significant role in various industrial products, with increasing demands for higher functionality driving the need for more advanced manufacturing processes. As these processes evolve, there is a growing need for enhanced techniques to evaluate powder properties. This report introduces two key devices developed by our company: the Parshe Analyzer^® (PAS) for particle shape and size analysis, and the E-SPART Analyzer^® (EST) for measuring particle charge distribution. These devices offer unique capabilities for precise particle characterization, meeting the sophisticated requirements of modern industrial applications.

Methods and Results: The PAS is a dynamic image analysis system used to measure particle size and shape. While laser diffraction and scattering methods are common for particle size distribution measurement, they lack the capability to evaluate particle shape and detect coarse particles within a sample. The PAS addresses these limitations by utilizing dynamic image analysis, allowing high-throughput measurement of a large number of particles suspended in liquid. With its flat sheath flow system, the PAS maintains precise focus, ensuring accurate measurements for particles ranging from sub-micron to over 100 μm. It also features automated lens switching and an optional auto-sampler for efficient sample dispersion.

A measurement example of silicon carbide (d₅₀=5.6 μm) using the PAS is provided. After ultrasonic dispersion, the particles were analyzed, revealing variations in particle detection depending on the proximity of adjacent particles. This demonstrates the PAS’s capability to deliver both quantitative and qualitative data on particle size and morphology.

The EST is a device that measures particle size and charge using laser Doppler technology. It evaluates phase delay caused by particle inertia in an acoustic field to determine size and calculates charge based on drift velocity in an electric field. Unlike bulk methods like the Faraday cage, the EST provides detailed charge distribution data for individual particles. To address issues with discontinued parts, a new version of the EST is under development, featuring digital signal processing, miniaturization, and improved mobility.

Conclusions (Outlook): The PAS and EST offer unique and precise insights into particle properties, providing advanced solutions for research and quality control applications. The ongoing development of these devices is expected to further support innovations in industries that require accurate particle characterization.

Background and Aims: In contemporary society, rapid digitalization is advancing, expanding IoT platforms in the manufacturing industry. Among these developments, interest in digital twin technology is growing. However, this technology requires advanced computational capabilities, posing significant technical challenges. Particularly in the field of powder technology, it is necessary to accurately consider the complex behavior of particles, making its realization difficult. To address these challenges, we have focused on measuring properties such as the angle of repose and bulk density using the powder property measuring device “Powder Tester”. In collaboration with DENSE Ltd., we have been developing a simulation model that forms the basis of digital twins in powder technology.

Methods and Results: To numerically evaluate the complex behavior of powders, we measured the angle of repose and bulk density using the Powder Tester^TM in collaboration with DENSE Ltd. Based on these measurements, we developed a simulation model applying a coarse-grained model for irregular particles. This model enables practical time analysis in powder simulations, which typically require enormous computational costs. By incorporating these measurements into our model, we were able to simulate the behavior of powders more efficiently. The simulation results showed good agreement with experimental data, validating the model’s accuracy and effectiveness in predicting powder behavior under various conditions. Additionally, we explored different simulation scenarios to assess the model’s robustness and flexibility, further confirming its potential for practical applications in the industry.

Conclusions and Outlooks: The development of this simulation model has demonstrated that the behavior of irregular particles can be analyzed within practical timeframes. This achievement is expected to contribute to advancing digital twin technology in powder technology. Future challenges include further improving this model and applying it to simulate a wider range of powder behaviors, ultimately enhancing the accuracy and efficiency of digital twins in various industrial applications. By continuing this research, we aim to overcome existing limitations and drive innovation in the field of powder technology. Our ongoing efforts will focus on integrating more complex particle interactions and refining the model to handle diverse powder properties, paving the way for more sophisticated digital twin solutions.

Introduction: In industrial settings, drying slurry and clay-like materials can be achieved through direct or indirect heating methods. The Solidaire^TM dryer, an indirect heating dryer, stands out due to its efficient combination of jacket heating and high-speed paddle agitation. This study explores new technological advancements in Solidaire to enhance its drying capabilities.

About Solidaire^TM: The Solidaire dryer indirectly transfers heat to the material via a heated jacket while agitating the material with high-speed rotating paddles, ensuring efficient and rapid drying. The internal structure includes a cylindrical casing with a surrounding heating jacket and a rotating paddle assembly. The paddles’ high rotating speed helps to break down agglomerates, reducing the residence time and minimizing heat damage to the material.

Experimental methods: A series of tests was conducted to evaluate the effects of increased paddle rotating speed and reduced clearance between the paddles and the casing. These tests used a prototype designed to achieve higher paddle speeds and adjustable clearance. Experiments were conducted using a lightweight calcium carbonate slurry (primary particle size 150 nm, 67% W.B.), which is prone to adhesion. The overall heat transfer coefficient and moisture content of the dried product were measured under various conditions.

Results and Discussion:

1. Clearance Effect: Reducing the clearance between the agitator paddles and the inner wall increased the overall heat transfer coefficient, likely because of a decrease in the thickness of the boundary layer (L_p in Fig. 3).

2. Paddle Speed Effect: Increasing the paddle peripheral speed from the standard 11 m/s to 22 and 33 m/s improved the overall heat transfer coefficient (Figs. 7–9). Higher speeds facilitated particle dispersion, increased contact between particles and the heated wall, and reduced adhesion.

3. Jacket Temperature Effect: Higher jacket temperatures (steam pressures) increased the overall heat transfer coefficient and reduced the moisture content of the dried product, as expected (Figs. 11–14).

4. Adhesion Reduction: Higher paddle speeds effectively reduced adhesion inside the dryer, which is a common issue in drying operations (Fig. 15).

Conclusions: The study demonstrated that increasing the paddle rotating speed and optimizing the clearance in the Solidaire^TM indirect heating dryer significantly improved the drying capacity by enhancing the overall heat transfer coefficient and reducing adhesion. These findings provide insights into the development of next-generation dryers with improved performance for various industrial applications.

Introduction: The Nauta Mixer^® is a powder mixer developed in the 1940s in the Netherlands for mixing animal feed. The machine consists of a conical body with a mixing screw attached to a rotating arm. The Nauta Mixer has several favorable attributes, such as mixing swiftly with low energy consumption, minimal damage to the powder particles, ease of discharge with a low amount of residue, and ease of cleaning, making use of multiple products easier. The mixer has been widely adopted worldwide, with over 20,000 units sold across various industries.

Nauta Mixer^® principle and design: The Nauta Mixer utilizes the principle of convective mixing, where the powder undergoes upward, downward, and spiral motions within the casing due to the rotation of the screw. The mixer design follows a geometric similarity, with the casing angle remaining constant across different capacities, while only the height varies. As the capacity increases, the screw length also increases proportionally. This design approach ensures consistent mixing performance across different mixer sizes.

Nauta Mixer^® types and features: The Nauta Mixer is available in three main types: NX, DBX, and VN. The VN type, introduced in 1997, features a compact and sanitary design with improved drive-unit integration. Compared with the DBX type, the VN type offers a smaller footprint and improved cleanability while maintaining mixing performance.

Case study: low-floor VN mixer: A case study is presented where a low-floor 5000-L VN Mixer was replaced a horizontal mixer, addressing issues such as poor powder discharge and blocking by powder. The low-floor design was achieved by cutting the bottom section while ensuring adequate mixing performance through design modifications.

Research on mixing time: Research on estimating the mixing time for the Nauta Mixer is discussed, highlighting the correlation between mixing time and various parameters, such as screw diameter, length, rotational speed, and Froude number. While empirical equations show good agreement for smaller capacities, deviations are observed for larger mixers, likely due to more active convective mixing at higher powder levels.

Conclusions: The Nauta Mixer provides efficient convective mixing with minimal shear and temperature rise, making it suitable for various applications. Hosokawa Micron continues to innovate and provide tailored solutions to meet a variety of customer requirements and applications.