Announcements

MDPI, the leading Open Access (OA) publisher, announced on Monday that it opened its Korean branch office on 29th April 2024. With this addition, MDPI now operates 21 offices in 12 countries worldwide. Claude Seo, with over 20 years of experience in the academic journal publishing industry, including Nature Publishing Group (NPG), has been appointed as the Office Manager of the Seoul office.

With the establishment of a Seoul office, MDPI aims to actively support Korea scientific communities to further promote the publication of OA journals in the region. As of the end of 2023, Korea ranked sixth worldwide in both submissions and publications of MDPI research papers. MDPI is the number one OA publisher in Korea.

Sungkyunkwan University Joins MDPI’s Institutional Open Access Program

In addition, MDPI announced that Sungkyunkwan University joined MDPI’s Institutional Open Access Program (IOAP). This program offers free access to MDPI online submission system for the institutions and APC discounts to affiliated authors. Thirteen major Korean universities, including Sungkyunkwan University, Kyung Hee University, Chung-Ang University and Catholic University of Korea, have adopted IOAP in Korea.

OA aims to break down barriers that have traditionally restricted access to science, ensuring that knowledge is available to all, regardless of financial situation or institutional affiliations. Authors, academia, and scientific communities are rapidly moving toward OA. MDPI has been at the forefront of reshaping the academic publishing landscape, with OA surpassing subscription-based publishing in 2020.

MDPI CEO Visits Seoul, Korea

In March, Stefan Tochev, Chief Executive Officer (CEO) of MDPI, visited Korea and met with various stakeholders including government agencies, research and academic institutions, universities. During his visit, Stefan highlighted that MDPI continues to pave the way for a world where science is accessible to all, supporting a global community of inclusive innovation and collaborative solutions.

Stefan expressed excitement about the new venture, stating, "Today marks a significant milestone for MDPI as we celebrate the opening of our new office in Seoul, Korea. This expansion is more than just an increase in our physical footprint, it is a pivotal step in our ongoing commitment to making scientific knowledge more accessible, participatory, and inclusive across the globe."

Claude Seo, reflecting on his new role, commented, "I am delighted to have been offered this position of trust within MDPI, the no. 1 scholarly OA publisher. As we establish our presence in Korea, we are dedicated to integrating into the local community and contributing to its vibrant culture. Our commitment goes beyond business growth; it is about creating a more informed and innovative society by embracing and promoting diversity within the scientific community.”

For further inquiries, please contact our Seoul office directly.

About MDPI

A pioneer in scholarly, open access publishing, MDPI has supported academic communities since 1996. MDPI is leading the transition to open science by making more research free and accessible to everyone. Over 3.3 million researchers have entrusted MDPI with publishing their scientific discoveries. MDPI’s editorial process is bolstered by a network of dedicated reviewers, a team of 6000 diligent, well-trained staff members, and an in-house article submission platform that was designed to ensure efficient processes within its 430 fully OA titles.

2. Can you share any experiences of overcoming challenges that you have faced in your research?
Surely, I encountered many difficulties and challenges; in the research field, when a problem is solved, it often appears trivial, and one has to move towards more difficult and challenging new goals.
I overcame the difficulties by studying, reading similar papers in the literature, exchanging information with colleagues, and participating in conferences. Of course, in the end, one’s intuition is a base requisite.

3. What do you believe the hot topics in the field of fluid mechanics research will be over the next few years, and why do you think these subjects will become important?
Fluid mechanics problems involve physical situations where many variables change rapidly in space and time; hence, to predict flow behavior, it is mandatory to work with reduced-order models to capture the essence of the physics with a relatively simple model. This need constitutes a modern research line, named reduced-order modeling, or modal decomposition analysis. Also, so-called data-driven models are a modern topic which can be used to reduce the complexity of the problem, drawing information from previous (numerical or experimental) knowledge or data.

4. With numerous conferences being organized each year, do you have any suggestions that might make our conference more meaningful for scholars and students?
Maybe the organization of mini-symposia on specific restricted topics could help potential participants recognize how to benefit from participation in the conference.

5. What are your thoughts on the current trends and developments of open access publishing?
Open access publishing speeds up the diffusion of information and new results. Also, the reduced time of revision of manuscripts is an important parameter. In my opinion, sometimes the costs are too high, especially for young independent researchers.

2. Have you encountered any challenges in your research?
In the realm of scientific investigation, we are perpetually confronted with a myriad of challenges. These encompass a broad spectrum, ranging from technical difficulties, the necessity for design enhancements, and the exploration of novel materials to the demands of our applications, among others.
Moreover, we grapple with substantial obstacles that are inherently tied to the constraints of physics. A case in point is the miniaturization of actuators, a task that becomes increasingly complex as the performance variables of interest inversely scale with volume or area. This scenario presents formidable challenges to both our creative capacities and the technologies at our disposal.

3. Could you share your experience of overcoming these issues?
Minor obstacles are surmounted through relentless diligence and perseverance, fortuitously culminating in the genesis of new scholarly publications and projects. More substantial challenges and innovative ideas persistently linger, serving as a source of inspiration for the research collective, particularly for nascent doctoral candidates. These challenges are not merely hurdles to overcome, but catalysts that drive our pursuit of knowledge and innovation.

4. What do you believe the hot topics in the field of miniature actuators research will be over the next few years, and why do you think these subjects will become important?
Based on recent trends and advancements, here are some potential hot topics in the field of miniature actuators research:

1. Material research: The development of new materials such as polymers, organic materials, piezoelectric materials, nitrides, shape memory alloys, thermoelectric materials, and other functional thin-film materials. These materials can significantly enhance the performance of miniature actuators;
2. Fabrication technologies: Innovative processes and fabrication technologies for miniaturized actuator systems are expected to be a major focus. This includes deposition techniques, lithography, etching and ablation techniques, hybrid technologies, and three-dimensional (3D) printing;
3. Functional surfaces: The creation of functional surfaces in actuator microdevices, such as hydrophobic/hydrophilic functionalization, tribological functions, and biomimetic surfaces;
4. Modeling and simulation: As the complexity of these systems increases, so does the need for more sophisticated modeling and simulation tools. This includes CAD tools and simulations, from the packaged systems down to the device level;
5. Actuation principles: Research into various physical actuation principles, such as electrostatic, piezoelectric, mechanical, thermal, acoustic, and magnetic, will continue to be important;
6. Bioactuators and artificial muscles: The development of chemical actuators and bioactuators, as well as artificial muscles, is a promising area of research;
7. System integration: The integration of miniature actuators into larger systems, including interface electronics, packaging and assembly, 3D integration techniques, micro-mechatronics, and micro-robotics, will be crucial;
8. Applications and markets: The exploration of new applications and markets for miniaturized actuators/micro-actuators, including monitoring, control, and measurement systems, will be a key area of focus.

These topics are driven by the increasing demand for smaller, more efficient, and more capable devices in a variety of fields, including robotics, biotechnology, and the Internet of Things (IoT). The miniaturization of robots with locomotion abilities is a challenge with a significant technological impact in many applications where large-scale robots have physical or cost restrictions.

5. As the session chair of IECAT2024, what kind of meeting you are looking forward to in particular?
In general, I am looking forward to gaining knowledge about the latest research and learning about the latest findings and methods in the field of actuators before they are even published in the journal.
Networking is also important for research teams, and a conference is a good opportunity to meet experts and like-minded individuals in our field, which can lead to collaborations and partnerships.
Interdisciplinary learning approaches, bringing together researchers from different areas, will clearly be a part of IECAT. Regarding career development, attending conferences can lead to learning about career-changing prospects and forging strong working relationships.

6. With numerous conferences being organized each year, do you have any suggestions that would make our conference more meaningful for scholars and students?
In order to enhance the value and impact of our conference, it would be beneficial to incorporate tutorials and webinars into our program. These sessions, led by esteemed researchers, could offer insights and nuances of their work that are typically not included in published papers. Additionally, scheduling an in-person gathering every two years could significantly increase the benefits of the conference, fostering stronger connections and collaborations among attendees. This hybrid model could provide a more comprehensive and enriching experience for all participants.
In addition, speaker incentives may also motivate submissions. Currently, the conference will provide six awards, including Best Oral Presentation Award and Best Poster Award. I would also like to propose waiving the Article Processing Charges (APCs) for keynote speakers and offering a greater discount than the currently announced 20% for invited speakers. As a nascent conference, I believe this would be a beneficial investment that could aid in its promotion.

2. Can you share any experiences of overcoming challenges that you have faced in your research?
I have made a breakthrough that could lead to photophones—devices without electrical connections that convert light energy directly into sound. Perhaps this discovery will help commercialize optical telephone networks. It could also allow robots to respond directly to light, again, without the need for wire connectors. This discovery is occasionally used to teach students about entrepreneurship.

Where did I come up with the idea for this light conversion? Not with the sunlight shining through my office window and not outside feeling the warmth of the sun, but I came up with the idea in a dimly lit karaoke bar. I was working on ceramic actuators—a kind of transducer that converts electrical energy to mechanical energy—at the Tokyo Institute of Technology when the trigger for “the light-controlled actuator” was initiated. In 1980, one of my friends, a precision-machine expert, and I were drinking together at a karaoke bar, where many Japanese people go, to enjoy drinks and our own singing. We called this activity our “after-5-o'clock meeting” in the pre-Twitter or Facebook period. At that time, my friend studied micro-mechanisms such as millimeter-sized walking robots. He explained that, as electrically controlled walking mechanisms become very small (on the order of a millimeter), they do not walk smoothly because the frictional force drops drastically, and the weight of the electric lead becomes more significant.

After a few drinks, it becomes easier to play “What if?” games. That is when he asked, “What if you, an expert on actuators, could produce a remote-controlled actuator? One that would bypass the electrical lead?” To many people, “remote control” equals controlled by radio waves, light waves, or sound. Light-controlled actuators require that light energy be transduced twice: First from light energy to electrical energy, and second from electrical energy to mechanical energy. These are “photovoltaic” and “piezoelectric” effects.

A solar cell is a well-known photovoltaic device, but it does not generate sufficient voltage to drive a piezoelectric device. So, my friend’s actuator needed another way to achieve a photovoltaic effect. Along with the drinking and singing, we enjoyed these intellectual challenges. I must have had a bit too much that night since I promised I would make such a machine for him. But I had no idea how to do it! While my work is applied research, I usually come home from scientific meetings about basic research with all kinds of ideas. At one of these meetings, about six months after my promise, a Russian physicist reported that a single crystal of lithium niobate produced a high electromotive force (10 kV/mm) under purple light. His talk got me excited. Could this material make the power supply for the piezoelectric actuator? Could it directly produce a mechanical force under purple light?

I returned to the lab and placed a small lithium niobate plate onto a plate of piezoelectric lead zirconate titanate. Then, I turned on the purple light and watched for the piezoelectric effect (mechanical deformation). But it was too slow, taking an hour for the voltage to get high enough to make a discernable shape change. Then, the idea hit me: what about making a single material that could be used for the sensor and the actuator? Could I place the photovoltaic and piezoelectric effects into a single asymmetric crystal? After lots of trial and error, I came up with a tungstate-doped material made of lead lanthanum zirconate titanate (PLZT) that responded well to purple light. It had a large piezoelectric effect and had properties that would make it relatively easy to fabricate.

To make a device out of this material, I pasted two PLZT plates back-to-back, but placed them in opposite polarization, and then connected the edges. I shined a purple light to one side, which generated a photovoltaic voltage of 7 kV across the length. This caused the PLZT plate on that side to expand by nearly 0.1% of its length, while the plate on the other (unlit) side contracted due to the piezoelectric effect through the photovoltage. The whole device bent away from the light. For this 20 mm long, 0.4 mm thick bi-plate, the displacement at the edge was 150 µm, and the response speed was 1 second. This fast and significant response was pretty exciting.

Remembering the promise to my friend, I fabricated a simple “light-driven micro walking machine,” with two bi-plate legs attached to a plastic board. When the light alternately irradiated each leg, the legs bent one at a time, and the machine moved like an inchworm. It moved without electric leads or circuits! That was in 1987, seven years after my promise.

I got busy with my “toy”, but not too busy to attend the “after-5-o’clock meetings” in Tokyo’s nightclub area. In 1989, at my favorite karaoke bar, I was talking about my device to another friend who worked for a telephone company. He wanted to know if the material could make a photo-acoustic device—perhaps as a solution to a major barrier in fiber-optic communication. The technology to transmit voice data—a phone call—at the speed of light through lasers and fiber optics had been advancing rapidly. But the end of the line—the ear speaker—limited the technology, since optical phone signals must be converted from light energy to mechanical movement via electrical energy.

I thought my material could convert light flashes directly into sound. I chopped two light beams to make a 180-degree phase difference and applied each beam to one side of the bi-plate. The resonance point, monitored by the tip displacement, was 75 Hz, just at the edge of the audible range for people! We’re now working to fabricate real photo-speakers (I call them “photophones”) and have ideas that may increase the vibration frequency several-fold to reproduce human speech correctly. Photophones could provide a breakthrough in optical communication.

Well, what is my message for you, dear reader? To find a noisy karaoke bar? Perhaps that is not necessary, but what is necessary is listening to others outside of your particular research area, for instance, basic researchers or people with specific, applied objectives.

3. What do you believe the hot topics in the field of piezoelectric actuator research will be over the next few years, and why do you think these subjects will become important?
Innovative materials and drive/control developments have not been seen in the past two decades, except for performance improvements. Thus, new application developments should be focused, aiming at million-selling products. The author comments on the paradigm shift from “econo-engineering” to politico-engineering in science and technology development. In the 1980s, i.e., the “Bubble Economy” period, cost/performance technologies were sought that fitted the governmental slogan, “lighter, thinner, shorter, smaller (軽薄短小)”, while, in the 2000s, sustainability and crisis technologies should be mainstream, alongside the slogan “cooperation, protection, reduction, continuation (協守減維)”. These trendy technologies are primarily initiated by political regulations.
The crises include the following:
(1) Natural disasters;
(2) Infectious/contagious diseases;
(3) Enormous accidents;
(4) Intentional terrorist/criminal incident;
(5) External and civil war/territorial invasion.

To the contrary, sustainability technologies were introduced in the following piezoelectric device areas, including medical applications:
(a) Non-toxic Pb-free piezo-materials;
(b) Ultrasonic disposal technology for hazardous materials;
(c) Reduction of contamination gas with piezo-devices;
(d) New energy source creation (i.e., piezoelectric energy harvesting);
(e) Energy-efficient piezoelectric device development;
(f) Medical acoustic probes and micro-disruptors for medical catheters.

I propose a new four-Chinese-character slogan for the era of “politico-engineering”, “協, 守, 減, 維 (cooperation, protection, reduction, and continuation)”. The standardization of internet systems and computer cables requires global “cooperation” and coordination to accelerate mutual communication. The “Paris Agreement” in 2016 is an international agreement on “Greenhouse Gas” regulation linked to the United Nations Framework Convention on Climate Change. “Protection” is mandatory for the territory and environment from the enemy or natural disaster and from pandemic disease spread. A “reduction” in toxic materials and energy consumption should be urged, then society’s “continuation” (or a sustainable society), in parallel with medical technology advancements, will be the ultimate desire. This development strategy is the key for the new generation of researchers.

4. As the conference chair, could you briefly describe what kind of meeting you are looking forward to in particular?
Let me explain the so-called “Google Syndrome”. The search engine Google went online in 1998. After this event, research approaches changed significantly. When I encourage them to research something new, most of my current Ph.D. graduate students take the following research steps: (1) search the recent research papers on the indicated topics on the Google search engine, (2) summarize the results, picking up the unstudied parts by believing that the already-published results are correct, and (3) set a research plan for himself/herself. Most recently, even the research plan/proposal is generated with ChatGPT. This “addiction” was named “Google Syndrome”. The important point is the fact that no completely new idea comes out because Google and ChatGPT can only generate the combined idea of already-published materials. I encourage young researchers to find a very innovative and unique idea, which the present Google does not include. Therefore, I am expecting this sort of unique paper, which does not include other groups’ paper citations.

5. With numerous conferences being organized each year, do you have any suggestions that might make our conference more meaningful for scholars and students?
Most of the current MDPI Actuators papers focus on performance improvement. In the drive/control area, for example, complicated mixed systems (including neuro networks) are reported, which I would say is “Spaghetti Syndrome”. I sincerely hope to collect very innovative and unique ideas for our conference, which present Google searches may not include.

6. Could you share some of your past conference experiences? Did these conferences assist you in promoting your research results, expanding your network, finding potential collaborators, advancing your career, etc.?
The International Conferences on Actuators and Transducers organized by the Penn State International Center for Actuators and Transducers were organized in that direction: (1) Only the eminent worldwide researchers were invited (a small number attendance less than 50), with both academic and industry researchers in a 50-50 ratio. (2) The invitees were selected from various fields, including physics, chemistry, ceramics, electrical, mechanical, computer engineering, etc. (3) By putting a long discussion time between each presentation, we encouraged researchers to find their future collaborators. (4) Students could demonstrate their capabilities to companies that they could join in the future.

7. What are your thoughts on the current trends and development of open access publishing?
Open access publication is good for disclosing a scientific idea quickly. Personally, considering intellectual property, I usually finish the patent and other IP applications first, followed by the report to the Research Contract Agencies. The publication, especially for open access, will be delayed typically by 4–5 years, after finishing all processes for commercialization.

Conference: 8th National Congress of Magnetic Materials and Devices
Date: 12–14 April 2024
Location: Hangzhou, China 

MDPI will attend the 8th National Congress of Magnetic Materials and Devices as an exhibitor. We invite researchers from different backgrounds to visit and share their latest ideas with us. 

The 8th National Congress of Magnetic Materials and Devices aims to gather domestic scientific and technological workers and industrial units to discuss the focus, hot spots, frontiers, and key common scientific issues in the field, share the latest results, explore basic research ideas and priority development directions, and promote technological progress and industrialization. Collaborate, grasp scientific research and industry development trends, and promote industry–university–research cooperation and leapfrog development. 

The following MDPI journals will be represented:

• Magnetochemistry;
• Actuators;
• Crystals;
• Hardware;
• Magnetism;
• Materials;
• Technologies;
• Vehicles. 

If you are planning to attend this conference, please do not hesitate to start an online conversation with us. Our delegates look forward to meeting you in person and answering any questions you may have. For more information about the conference, please visit the following website: http://www.c-nmaterial.com.cn/index.php.

Conference: Canadian Society for Mechanical Engineering International Congress and 31st Annual Conference of the CFD Society of Canada (CSME/CFD2024)
Organization: Canadian Society for Mechanical Engineering (CSME) and the CFD Society of Canada (CFDSC)
Date: 26–29 May 2024
Place: University of Toronto, Toronto, Canada

MDPI journals will be attending the Canadian Society for Mechanical Engineering International Congress and 31st Annual Conference of the CFD Society of Canada (CSME/CFD2024) as an exhibitor. This meeting will be held in Toronto, Canada, from 26 to 29 May 2024.

The Canadian Society for Mechanical Engineering International Congress and 31st Annual Conference of the CFD Society of Canada is an annual meeting and represents a marvellous opportunity for the mechanical engineering and CFD communities in Canada and beyond to come together to exchange the latest research results and to build a community, as it brings together students and professors with colleagues from industry and government.

The following MDPI journals will be represented:

• Machines;
• Fluids;
• Micromachines;
• Aerospace;
• Inventions;
• Drones;
• Eng;
• Technologies;
• Actuators;
• Automation;
• Journal of Manufacturing and Materials Processing (JMMP);
• Robotics;
• Journal of Experimental and Theoretical Analyses (JETA);
• Modelling.

If you are attending this conference, please feel free to start a conversation with us. Our delegates look forward to meeting you in person and answering any questions you may have. For more information about the conference, please visit the following link: https://www.csmecongress.org/.

In recognizing the exceptional efforts of our reviewers in 2023, we express our sincere gratitude for upholding the high standards of Actuators. Their commitment ensured the rigorous peer review that is integral to quality academic publishing.

In 2023, Actuators received 1686 review reports, from 1287 reviewers. This past year, we worked with reviewers from 63 countries and regions, reflecting the diversity in our collaboration with research communities. Their dedication shapes scholarly discourse and advances global research. The editorial team expresses gratitude for the vital role played by each reviewer in the Actuators family throughout 2023, and we look forward to their continued support in 2024.

The following are the reviewers who have consented to show their names: