Predicting the Structures and Associated Phase Transitions Mechanisms in Disordered Crystals via a Combination of Experimental and Theoretical Methods

Ruggiero, Michael T., Johanna Kölbel, Qi Li, and J. Axel Zeitler. "Predicting the Structures and Associated Phase Transitions Mechanisms in Disordered Crystals via a Combination of Experimental and Theoretical Methods." Faraday Discussions (2018).

Abstract

Disordered materials make up a large portion of condensed phase systems, but the difficulties in describing their structures and molecular dynamics limit their potential applications. Disordered crystalline systems, also known as plastic crystals, offer a unique perspective into these factors because the system retains a degree of crystallinity, reducing the degrees of freedom that must be explored when interpreting the results. However, while disordered crystals do diffract X-rays, it is difficult to fully resolve a meaningful crystalline structure, with the best scenario resulting in lattice parameters. In this study, we use a combination of experimental terahertz time-domain spectroscopy, and theoretical solid-state ab initio density functional theory and molecular dynamics simulations to fully elucidate the structures and associated dynamics of organic molecular solids. The results highlight that this combination provides a complete description of the energetic and mechanistic pathways involved in the formation of disordered crystals, and highlights the importance of low-frequency dynamics on their properties. Finally, with structures fully determined and validated by the experimental results, recent progress into anharmonic calculations, namely the quasi-harmonic approximation method, enables full temperature and pressure-dependent properties to be understood within the framework of the potential energy hyper-surface structure.

for full paper see http://pubs.rsc.org/en/content/articlepdf/2018/FD/C8FD00042E

"A corresponding pellet containing pure polyethylene was also made to act as a standard blank for absorption measurements. All experimental THz-TDS spectra were obtained using a commercial TeraPulse 4000 spectrometer (TeraView Ltd., Cambridge,UK). Variable-temperature measurements were performed using a liquid nitrogen cryostat (Janis, Massachusetts, USA) equipped with a externally controlled heating element (Lakeshore 330, Ohio, USA)."

For information about TeraView see: teraview.com

For information about Janis see https://www.janis.com/

A quantitative comparison of in-line coating thickness distributions obtained from a pharmaceutical tablet mixing process using discrete element method and terahertz pulsed imaging

Pei, Chunlei, Hungyen Lin, Daniel Markl, Yao-Chun Shen, J. Axel Zeitler, and James A. Elliott. "A quantitative comparison of in-line coating thickness distributions obtained from a pharmaceutical tablet mixing process using discrete element method and terahertz pulsed imaging." Chemical Engineering Science (2018).

Abstract

The application of terahertz pulsed imaging (TPI) in the in-line configuration to monitor the coating thickness distribution of pharmaceutical tablets has the potential to improve the performance and quality of the spray coating process. In this study, an in-line TPI method is used to measure coating thickness distributions on pre-coated tablets during mixing in a rotating pan, and compared with results obtained numerically using the discrete element method (DEM) combined with a ray-tracing technique. The hit rates (i.e. the number of successful coating thickness measurements per minute) obtained from both terahertz in-line experiments and the DEM/ray-tracing simulations are in good agreement, and both increase with the number of baffles in the mixing pan. We demonstrate that the coating thickness variability as determined from the ray-traced data and the terahertz in-line measurements represents mainly the intra-tablet variability due to relatively uniform mean coating thickness across tablets. The mean coating thickness of the ray-traced data from the numerical simulations agrees well with the mean coating thickness as determined by the off-line TPI measurements. The mean coating thickness of in-line TPI measurements is slightly higher than that of off-line measurements. This discrepancy can be corrected based on the cap-to-band surface area ratio of the tablet and the cap-to-band sampling ratio obtained from ray-tracing simulations: the corrected mean coating thickness of the in-line TPI measurements shows a better agreement with that of off-line measurements.

For full paper see https://www.sciencedirect.com/science/article/pii/S0009250918304172

… the terahertz in-line measurement. A TPI Imaga 2000 system (TeraView Ltd., Cambridge, UK) was used to perform the off-line measurements as described in detail by Shen and Taday (2008). During the measurement, each...... 

Investigating elastic relaxation effects on the optical properties of functionalised calcium carbonate compacts using optics-based Heckel analysis

Bawuah, Prince, Anssi-Pekka Karttunen, Daniel Markl, Cathy Ridgway, Ossi Korhonen, Patrick Gane, J. Axel Zeitler, Jarkko Ketolainen, and Kai-Erik Peiponen. "Investigating elastic relaxation effects on the optical properties of functionalised calcium carbonate compacts using optics-based Heckel analysis." International journal of pharmaceutics 544, no. 1 (2018): 278-284.

for full paper see https://www.sciencedirect.com/science/article/pii/S0378517318302710

The group used a terahertz  a Terapulse 4000 spectrometer (Teraview Ltd., Cambridge, UK) in transmission mode.

Abstract

Heckel analysis is a widely used method for the characterisation of the compression behaviour of pharmaceutical samples during the preparation of solid dosage formulations. The present study introduces an optical version of the Heckel equation that is based on a combination of the conventional Heckel equation together with the linear relationship defined between the effective terahertz (THz) refractive index and the porosity of pharmaceutical tablets. The proposed optical Heckel equation allows us to, firstly, calculate the zero-porosity refractive index, and, secondly, predict the in-die development of the effective refractive index as a function of the compressive pressure during tablet compression. This was demonstrated for five batches of highly porous functionalised calcium carbonate (FCC) excipient compacts. The close match observed between the estimated in-die effective refractive index and the measured/out-of-die effective THz refractive index supports the validity of the proposed form of the equation. By comparing the measured and estimated in-die tablet properties, a clear change in the porosity and hence, the effective refractive index, due to post-compression elastic relaxation of the FCC compacts, has been observed. We have, therefore, proposed a THz-based compaction setup that will permit in-line monitoring of processes during tablet compression. We envisage that this new approach in tracking powder properties introduced in this preliminary study will lead to the onset of further extensive and detailed future studies.

Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications XII @ Photonics West 2019

Important
Dates

SHOW | HIDE

Abstract Due:
25 July 2018

Author Notification:
1 October 2018

Manuscript Due Date:
9 January 2019

Conference
Committee

SHOW | HIDE

Conference Chairs

• Laurence P. Sadwick, InnoSys, Inc. (United States)
• Tianxin Yang, Tianjin Univ. (China)

Program Committee

• René Beigang, Technische Univ. Kaiserslautern (Germany)
• Jianji Dong, Huazhong Univ. of Science and Technology (China)
• Frank Ellrich, Technischen Hochschule Bingen (Germany)
• Fabian Friederich, Fraunhofer-Institut für Physikalische Messtechnik (Germany)
• Robert H. Giles, Univ. of Massachusetts Lowell (United States)
• R. Jennifer Hwu, InnoSys, Inc. (United States)

Program Committee continued...

• Mona Jarrahi, Univ. of California, Los Angeles (United States)
• J. Anthony Murphy, National Univ. of Ireland, Maynooth (Ireland)
• Créidhe O'Sullivan, National Univ. of Ireland, Maynooth (Ireland)
• Kyung Hyun Park, Electronics and Telecommunications Research Institute (Korea, Republic of)
• Alessia Portieri, TeraView Ltd. (United Kingdom)
• Jinghua Teng, Institute of Materials Research and Engineering (IMRE) (Singapore)
• Michael Weibel, Joint Research and Development, Inc. (United States)
• Jiangfeng Zhou, Univ. of South Florida (United States)

Call for
Papers

This conference brings together researchers and engineers from academia, industry, and government laboratories to explore and present work in the frequency range covering approximately less than 1 GHz (300 mm) to greater than 3 THz (100 μm) as well as infra-red including near, mid and far infrared. Papers on RF and millimeter and infrared technology including advances in wireless communications, radar, lidar, microwave and mm-wave photonics, metamaterials, antennas, phased array radar, modulation, security, monitoring, detection, imaging are encouraged. Papers in photonic-related fields including, but not limited to, radio over fiber (RoF) RF photonics including photonic generation of microwave signals, photonic processing of microwave signals, and photonic distribution of microwave signals and semiconductor (including Si, SiC, SOI, GaAs, GaN, InP, SiGe, diamond, graphene and other materials) RF, mm-wave and terahertz devices and related applications are also encouraged, as well as the hybrid photonic systems and applications. Terahertz (THz) technology deals with the generation and utilization of electromagnetic energy covering what is also known as the sub-millimeter wave region of the spectrum. In this region, which lies between the millimeter wave and far infrared spectral regions, materials exhibit properties that can be exploited to advantage for use over a broad range of important technologies and applications. Papers on terahertz photonics including photonic generation and detection of terahertz waves to/or infrared, THz to/or infrared lasers are also encouraged. 

This conference includes low- to high-power sources, detectors, amplifiers, systems, including both photonic and electronic modulated sources, detectors, and systems as well as nanodevices, nanomaterials, nanotechnology, nanostructures, etc. At THz frequencies, the primary difficulty encountered by scientists and engineers working in this field is the lack of convenient and affordable sources and detectors of terahertz radiation, but this difficulty is gradually changing as new sources and improved detectors are being developed as the technology continues to mature and broaden. At RF and millimeter frequencies, more and more hybrid systems are being integrated with photonic devices that enhance the functions, specifications and stabilities tremendously compared to their traditional counterpart systems. The purpose of this conference is to gather scientists and engineers from a diverse set of disciplines, who are interested in either learning more about terahertz and sub-millimeter and millimeter wave and RF technology and related and coupled technologies, or who are contributing to the field through their own research, development, or manufacturing activities. 

This conference also includes hybrid technologies including, for example, microwave to THz wearable devices of any type and form as well as microwave to THz communications and data links, Artificial intelligence in microwave toThz imaging, etc. 

Disciplines utilizing terahertz technology include physical chemistry (certain molecules or molecular segments exhibit strong resonances in the 10 cm-1 to 100 cm-1 spectral region), military, and homeland security (terahertz radiation can penetrate clothing and packing materials but is reflected by metals and other materials), biomedical technology (tissue exhibits reflection and absorption properties that change dramatically with tissue characteristics), medical and dental, secure short-distance wireless communications (atmospheric water content prevents terahertz radiation from traveling very far), astronomy (the cold background of the universe exhibits a peak in this spectral region), space communications (where the terahertz region is wide open for use) and other disciplines where new, yet-to-be-discovered applications will undoubtedly come forth. Since the low energy associated with terahertz radiation is expected to be no more harmful than infrared or microwave radiation, safety issues are not expected to limit the use of terahertz radiation at low-power levels. 

Papers on power supplies and electronic power conditioners and associated power protection systems including energy-efficient power supplies are also encouraged. 

Papers are solicited in the following and related areas: 

Terahertz sources

• solid-state sources, electron-beam sources, vacuum electronics sources, frequency mixers, frequency multipliers, parametric oscillators, hybrids, graphene, FET and HEMT sources, gas lasers, quantum cascade lasers and related sources, p-germanium sources, photoconductive switches, resonant tunneling diodes, backward wave oscillators
• novel stabilized photonic THz sources
• fabrication processes
• high bandwidth devices, structures, sources, detectors, sensors, etc.
• wearables
• systems and systems integration.

RF, sub-millimeter-wave and millimeter-wave sources

• power sources of all types in the range of 1 GHz to 300 GHz and 300 GHz and higher (i.e. from S-band to the higher end of the millimeter-wave frequencies and all of the sub-millimeter-wave frequency region)
• novel stabilized photonic RF, millimeter-wave, sub-millimeter-wave sources.

Detectors

• bolometers and other thermal detectors, Schottky and other mixers, thermopiles, quantum devices, antenna integrated detectors, heterodyne detection techniques, hybrid detection, direct detection techniques
• transistor-based detectors including graphene, silicon, III-V, II-VI, nitride-based, etc.
• theoretical modeling
• novel detectors.

High-power sources, modules, and systems

• THz, RF, millimeter-wave and sub-millimeter-wave high power sources
• THz, RF, millimeter-wave and sub-millimeter-wave modules
• THz, RF, millimeter-wave and sub-millimeter-wave systems
• power supplies and support circuits, electronics, optoelectronics, systems.

Terahertz, RF, millimeter-wave, and sub-millimeter-wave passive components

• optics, lenses, gratings, waveguides, photonic crystal structures and metamaterials, couplers, wire guides, other components.

Materials for THz and GHz devices

• linear and nonlinear optical materials and devices
• organic and inorganic source and modulator materials and devices
• RF, millimeter-wave and sub-millimeter-wave materials, devices and fabrication processes
• THz and/or GHz material systems
• silicon (Si)-based
• silicon carbide (SiC)-based
• silicon-on-insulator (SOI)-based
• gallium arsenide (GaAs)-based
• gallium nitride (GaN)-based
• indium phosphide (InP)-based
• silicon germanium (SiGe)-based
• quantum dot-(QD) based including for QDs for sensors, detectors and sources
• diamond-based
• graphene-based
• other-based.

Enhancements, improvements and advances in RF, millimeter-wave and sub-millimeter wave generation, modulation and detection

• RF, millimeter-wave and sub-millimeter-wave integrated photonic devices
• RF, millimeter-wave and sub-millimeter-wave and photonic integration process development
• RF, millimeter-wave and sub-millimeter-wave performance characterization
• phased-array and single-element photonically-driven antennas
• phased-array and single-element antennas, systems, concepts, approaches
• low-Vp and wide-bandwidth modulators
• direct-driven millimeter-wave lasers and amplifiers
• millimeter-wave, sub-millimeter and THz photonic crystal devices and applications
• RF, millimeter-wave, sub-millimeter-wave and THz photonic up- and down-converters
• photonic phase locked loops
• RF, millimeter-wave, sub-millimeter-wave, and THz MMICs
• wearables
• RF, millimeter-wave, sub-millimeter-wave, high power solid-state and electronic vacuum devices.

Simulations and modeling

• simulations and/or modeling of RF devices, components, and/or systems
• simulations and/or modeling of millimeter-wave devices, components, and/or systems
• simulations and/or modeling of sub-millimeter-wave devices, components, and/or systems
• simulations and/or modeling of THz devices, components, and/or systems
• modeling of optical components, optical systems, imaging systems, wave propagation, modes, Gaussian beam characteristics, couplers, antennas, performance limitations, software designs
• artificial intelligence, augmented reality, virtual reality.

Spectroscopy

• terahertz and/or sub-millimeter spectroscopy, DNA segment identification, cell abnormalities, cancer identification and screening, imaging, medical and dental detection
• infrared spectroscopy
• identification of biological and chemical detection and fingerprinting
• identification of hazardous, explosive, and/or dangerous materials
• identification of chemical or biological threats
• scalar and vector network analysis at sub-millimeter and terahertz frequencies
• measurement techniques at sub-millimeter, millimeter, and terahertz frequencies
• identification of organic and inorganic compounds using terahertz and/or sub-millimeter wave spectroscopy
• high-speed and/or high-resolution spectroscopic techniques, methods, approaches
• artificial Intelligence, augmented reality, virtual reality, etc.
• novel approaches, systems, designs, techniques, reflection, sensitivity, applications.

Biomedical applications

• DNA identification, burn analysis, tissue abnormality identification, pharmaceutical, dentistry, medical, clinical, commercial applications
• cancer, burn, and/or water content detection; high sensitivity, high contrast, etc.
• biological and/or physiological aspects and/or related effects of RF, millimeter-wave, sub-millimeter-wave and/or THz
• artificial Intelligence, augmented reality, virtual reality, etc.
• imaging techniques, methods, hardware design, strategies, technologies and techniques.

Communication and sensing systems

• terahertz, RF, millimeter-wave and sub-millimeter-wave communications, media characteristics, wireless communications, inspection systems, detection systems, screening systems
• RF, millimeter, sub-millimeter-wave and microwave links
• RF, millimeter-wave, sub-millimeter-wave photonic communication and sensing systems
• Internet of things (IOT) sensors, detectors and communication interfaces, protocols and implementations including but not limited to wireless sensors and wireless communications.

Imaging and security

• RF imaging devices, components, and/or systems
• millimeter-wave imaging devices, components, and/or systems
• sub-millimeter-wave imaging devices, components, and/or systems
• THz imaging devices, components, and/or systems
• RF, millimeter-wave and sub-millimeter-wave active and passive imaging systems
• artificial Intelligence, augmented reality, virtual reality, etc.
• x-ray imaging including components, systems, power supplies, applications, techniques, etc.

Astronomy and space and other areas of photonics, light, and matter

• imaging techniques, ultra-sensitive detection, applications, programs
• artificial Intelligence, augmented reality, virtual reality, etc.
• satellite communications
• space based electronics and devices
• satellite components and systems
• space and satellite qualifications and testing
• radiation hard electronics
• high-energy physics and related topics
• fusion and related topics
• fission and related topics.

Innovations

• new or novel terahertz, RF, millimeter-wave and sub-millimeter, microwave concepts, systems, applications
• new or novel developments in THz or sub-millimeter waves including teaching, instruction, course offerings, simulations, conceptional and/or experimental procedures, implementations, concepts, etc.
• wearables, implantable, etc.

Power supplies and electronic power conditioners

• high-power power supplies
• low- and ultra-low-power power supplies
• low-noise power supplies
• high- and ultra-efficient power supplies
• associated power protection systems
• energy-efficient power supplies
• novel designs and architectures
• specialized power electronics
• portable power supplies
• power supplies tailored for photonics and/or RF, mm-wave and/or THz applications
• power supplies for lighting applications including solid state lighting such as LEDs, OLEDs and quantum dots.

Organic electronics

• DC and low frequency
• high frequency
• novel designs and architectures
• passive and active addressable arrays
• low power
• modulated configurations
• sensing, detection and/or emitting
• organic light emitting diodes and associated electronics
• lighting therapy using solid state lighting including OLEDs.

Infrared devices, communications, sources, sensors, detectors

• infrared amplifiers
• infrared imaging devices, components, and/or systems
• infrared sources devices, components, and/or systems
• infrared sensors, detectors and/or associated devices, components, and/or systems
• infrared communications devices, components, and/or systems
• infrared active and passive components and/or systems
• infrared advances including components, systems, power supplies, applications, techniques, etc.
• infrared applications
• wearables
• artificial Intelligence, augmented reality, virtual reality,

Terahertz pulsed imaging reveals the stratigraphy of a seventeenth-century oil painting

Locquet, A., J. Dong, M. Melis, and D. S. Citrin. "Terahertz pulsed imaging reveals the stratigraphy of a seventeenth-century oil painting." In Unconventional Optical Imaging, vol. 10677, p. 106771Z. International Society for Optics and Photonics, 2018.

Terahertz pulsed imaging has attracted considerable interest for revealing the stratigraphy and hidden features of art paintings. The reconstruction of the stratigraphy is based on the precise extraction of THz echo parameters from the reflected signals. Several historical panel paintings and wall paintings have been well studied by THz reflective imaging, in which the detailed stratigraphy has been successfully revealed. To our knowledge, however, the stratigraphy of oil paintings has not been clearly uncovered by THz imaging, since the paint layers in an oil painting on canvas, especially for the 16th and 17th century art works, are usually very thin (~10 μm) in the THz regime. Therefore, in order to improve the performance of THz imaging, advanced signal-processing techniques with higher depth-resolution are still needed. In this study, THz reflective imaging is employed to reveal for the first time the detailed stratigraphy of a 17th century Italian oil painting on canvas. The paint layers on the supporting canvas are very thin in the THz regime, as the THz echoes corresponding to the stratigraphy totally overlap in the first cycle of the reflected THz signal. THz sparse deconvolution based on an iterative shrinkage algorithm is utilized to resolve the overlapping echoes. Based on the deconvolved signals, the detailed stratigraphy of this oil painting on canvas, including the varnish, pictorial, underdrawing, and ground layers, is successfully revealed. The THz C- and B-scans based on the THz deconvolved signals also enable us to reveal the features of each layer. Our results thus enhance the capability of terahertz imaging to perform detailed analysis and diagnostics of historical oil paintings on canvas with foreseen applications for the study of the artist’s technique and for authentication.

for full paper see https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10677/106771Z/Terahertz-pulsed-imaging-reveals-the-stratigraphy-of-a-seventeenth-century/10.1117/12.2306771.short?SSO=1&tab=ArticleLink

Also see teraview.com