Ratchapak Chitaree

Bio: Ratchapak Chitaree is an academic researcher from Mahidol University. The author has contributed to research in topics: Polarization (waves) & Interferometry. The author has an hindex of 5, co-authored 35 publications receiving 143 citations. Previous affiliations of Ratchapak Chitaree include Chiang Mai University.

Fiber in-line Mach-Zehnder interferometer based on an inner air-cavity for high-pressure sensing.

Abstract: We demonstrate a fiber in-line Mach–Zehnder interferometer based on an inner air-cavity with open micro-channel for high-pressure sensing applications. The inner air-cavity is fabricated by combining femtosecond laser micromachining and the fusion splicing technique. The micro-channel is drilled on the top of the inner air-cavity to allow the high-pressure gas to flow in. The fiber in-line device is miniature, robust, and stable in operation and exhibits a high pressure sensitivity of ∼8,239 pm/MPa.

Design and Characterization of Porous Core Polarization Maintaining Photonic Crystal Fiber for THz Guidance

Abstract: An improved design of Teflon photonic crystal fiber with a porous air-core is presented for low-loss terahertz guidance. Optimization of total power confinement in the air-holes, together both in the cladding and core regions, is carried out for both quasi-TE and quasi-TM polarizations by using a full-vectorial finite element method. To achieve the polarization maintenance, modal birefringence is enhanced by destroying the circular symmetry with the introduction of unequal size air-holes in the first ring.

Probing Thai Freshmen Science Students’ Conceptions of Heat and Temperature Using Open-Ended Questions: A Case Study

Abstract: The purpose of this study was to investigate the alternative conceptions held by Thai first year science students. A total of 334 first year science students have been tested before the regular first year university instruction on the thermal physics topic began. The first open-ended question for investigating students’ conceptions on term temperature, heat, latent heat, specific heat capacity and thermal equilibrium. The second open-ended question for investigating level of students’ conceptions of heat conduction. Students’ conceptions in each concept were identified into different categories and levels of understanding. The study showed that students’ written responses have some common specific misconceptions and different levels of understandings. Most students were unable to offer a correct reason for their answers. The results of this study may imply the teaching style in Thai high schools that may be problematic. In addition, the students’ misconceptions found could be used as a guide for developing proper teaching methods on the introductory physics course especially in the topic of thermal physics.

The rotating linearly polarized light from a polarizing Mach–Zehnder interferometer: Production and applications

Abstract: The production and control of a required polarization state are very important in optical measurements such as thin film surface characterization, ensuring continuity of data measurement and speedy acquisition. In this paper, a polarizing Mach–Zehnder interferometer is used to generate rotating linearly polarized light. Theoretical analysis and experimentation on the proposed configuration show good agreement. Applications of the rotating linearly polarized light generated from the proposed polarizing interferometer are demonstrated. The applications include measurements of the phase retardation of several wave retarders. The results from the preliminary investigation show a promising performance of the proposed setup.

Surveying Thai and Sydney introductory physics students’ understandings of heat and temperature

Abstract: In 2005 a project was undertaken at Mahidol University of Thailand. The aim of the project was to measure introductory students’ conceptual understanding of heat and temperature. In 2006 the project has been extended to the University of Sydney with the additional aim of comparing across the Universities. Students’ conceptual understanding of heat and temperature is being measured using the Heat and Temperature Conceptual Evaluation survey. A total of 910 Thai and 317 Australian students have been tested after standard first year university instruction on thermal physics. This paper compares Thai and Australian students’ conceptual understandings post instruction. Preliminary findings indicate that both Thai and Australian students have significant misconceptions relating to phase change and the rate of heat transfer. Commonalities indicate that the Thai version of the HTCE survey compares well with the English version.

Optical fiber sensing for marine environment and marine structural health monitoring: A review

Abstract: Optical fiber sensors have attracted considerable attention for marine environment and marine structural health monitoring, owing to advantages including resistance to electromagnetic interference, durability under extreme temperature and pressures, light weight, high transmission rate, small size and flexibility. In this paper, the optical fiber sensors employed for marine environment and marine structural health monitoring are summarized for the understanding of their basic sensing principles, and their various sensing applications such as physical parameters, chemical parameters and structural health monitoring. This review paper shows the feasibility of using optical fiber sensing technology for marine application and, due to the aforementioned advantages, it is possible to envisage a widespread use in this research field in the next few years.

Five easy lessons : strategies for successful physics teaching / Randall D. Knight

Abstract: Preface iiiI TEACHING INTRODUCTORY PHYSICS1. IntroductionDesired Student Outcomes Five Lessons for Teachers Toward an Active-Learning Environment Does it Work?2. Teaching Introductory Physics Things to Consider Laboratories and Recitations 3. Physics Education ResearchWhat is Physics Education Research?Summary of Findings from Physics Education Research Examples of Students' Alternative Conceptions Knowledge Structures and Problem Solving Implications for Instruction - The Five Lessons4. An Active-Learning ClassroomSo What's Wrong with Lectures?Active Learning A Dozen Things you can do to Change Physics Education Just the FAQsII TOPICS IN INTRODUCTORY PHYSICS 5. Introduction 6. Vectors and Mathematics 7. Motion and Kinematics8. Forces and Newton's Laws 9. Impulse and Momentum 10. Energy 11. Oscillations12. Waves 13. Thermal Physics 14. Thermodynamics 15. Electrostatics 16. Electric Fields 17. The Electric Potential 18. Current and Conductivity 19. DC Circuits 20. Magnetic Fields 21. Electromagnetic Induction 22. Geometrical Optics 23. Physical Optics 24. Quantum Physics References and Resources

First Decade of Interfacial Iontronic Sensing: From Droplet Sensors to Artificial Skins

Abstract: Over the past decade, a brand-new pressure- and tactile-sensing modality, known as iontronic sensing has emerged, utilizing the supercapacitive nature of the electrical double layer (EDL) that occurs at the electrolytic-electronic interface, leading to ultrahigh device sensitivity, high noise immunity, high resolution, high spatial definition, optical transparency, and responses to both static and dynamic stimuli, in addition to thin and flexible device architectures. Together, it offers unique combination of enabling features to tackle the grand challenges in pressure- and tactile-sensing applications, in particular, with recent interest and rapid progress in the development of robotic intelligence, electronic skin, wearable health as well as the internet-of-things, from both academic and industrial communities. A historical perspective of the iontronic sensing discovery, an overview of the fundamental working mechanism along with its device architectures, a survey of the unique material aspects and structural designs dedicated, and finally, a discussion of the newly enabled applications, technical challenges, and future outlooks are provided for this promising sensing modality with implementations. The state-of-the-art developments of the iontronic sensing technology in its first decade are summarized, potentially providing a technical roadmap for the next wave of innovations and breakthroughs in this field.

Recent Progress of Miniature MEMS Pressure Sensors.

Abstract: Miniature Microelectromechanical Systems (MEMS) pressure sensors possess various merits, such as low power consumption, being lightweight, having a small volume, accurate measurement in a space-limited region, low cost, little influence on the objects being detected. Accurate blood pressure has been frequently required for medical diagnosis. Miniature pressure sensors could directly measure the blood pressure and fluctuation in blood vessels with an inner diameter from 200 to 1000 m. Glaucoma is a group of eye diseases usually resulting from abnormal intraocular pressure. The implantable pressure sensor for real-time inspection would keep the disease from worsening; meanwhile, these small devices could alleviate the discomfort of patients. In addition to medical applications, miniature pressure sensors have also been used in the aerospace, industrial, and consumer electronics fields. To clearly illustrate the "miniature size", this paper focuses on miniature pressure sensors with an overall size of less than 2 mm × 2 mm or a pressure sensitive diaphragm area of less than 1 mm × 1 mm. In this paper, firstly, the working principles of several types of pressure sensors are briefly introduced. Secondly, the miniaturization with the development of the semiconductor processing technology is discussed. Thirdly, the sizes, performances, manufacturing processes, structures, and materials of small pressure sensors used in the different fields are explained in detail, especially in the medical field. Fourthly, problems encountered in the miniaturization of miniature pressure sensors are analyzed and possible solutions proposed. Finally, the probable development directions of miniature pressure sensors in the future are discussed.