Vibration, Control and Stability of Dynamical Systems

From Preface: This is the fourteenth time when the conference “Dynamical Systems: Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the Committee of Mechanics of the Polish Academy of Sciences and Ministry of Science and Higher Education of Poland. It is a great pleasure that our invitation has been accepted by recording in the history of our conference number of people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcomed over 180 persons from 31 countries all over the world. They decided to share the results of their research and many years experiences in a discipline of dynamical systems by submitting many very interesting papers. This year, the DSTA Conference Proceedings were split into three volumes entitled “Dynamical Systems” with respective subtitles: Vibration, Control and Stability of Dynamical Systems; Mathematical and Numerical Aspects of Dynamical System Analysis and Engineering Dynamics and Life Sciences. Additionally, there will be also published two volumes of Springer Proceedings in Mathematics and Statistics entitled “Dynamical Systems in Theoretical Perspective” and “Dynamical Systems in Applications”

Chemical Approaches for Nanofabrication Based on Colloidal Lithography with Organosilanes, Nanoparticles and Nickel Films: The Role of Water in Directing Surface Self-Assembly

The capabilities for accomplishing fundamental surface studies with molecular systems are demonstrated in this dissertation using measurement and imaging modes of scanning probe microscopy. Model systems were chosen for investigations of surface self-assembly mechanisms, with an emphasis on understanding the role of interfacial water in surface reactivity. A key strategy for molecular level studies was to prepare nanostructures using protocols with colloidal lithography and scanning probe-based lithography (SPL). Nanofabricated samples were characterized ex situ with contact and tapping-mode atomic force microscopy (AFM) after key reaction steps, providing direct views of changes in surface morphology at the nanoscale. Magnetic sample modulation (MSM) combined with contact mode AFM provided a route to detect the vibration of magnetic nanomaterials in response to an externally applied electromagnetic field. Nanoscale measurements of the size-scaling effects for physical properties such as conductance and nanomagnetism are contemporary topics in the field of nanoscience. Protocols of SPL were used for studies with organic thin films; nanoshaving and nanografting experiments provided a means to prepare ultra-small nanostructures. Nickel-coated nanostructures were constructed on amine-terminated nanorings of aminopropyltriethoxysilane (APTES) using colloidal lithography and chemical steps of electroless deposition (ELD), nickel was deposited by an autocatalytic redox reaction using palladium as a catalyst. Protocols were developed to investigate the role of water in the association and placement of silane molecules on surfaces as a strategy for indirectly tracking the location of water on surfaces. Visible light photocatalysis was used to prepare nanostructured films by immersing surface masks of monodisperse spheres in solutions of an aryl halide and then irradiating the solution with blue light. Films of aryl halide are linked to the surface by C-Au bonds to form robust films that resist the effects of oxidation. Nanostructured films of octaethylporphyrin (OEP) were prepared with immersion particle lithography by reaction with silicon tetrachloride. Porphyrins bound to the surface through covalent Si-O-surface linkages coordinated to the centers of the macrocycles in a kebob arrangement. The Si-O-Si “skewer” strategy was also successful for encapsulating Au nanoparticles with porphyrins to make core-shell nanoparticles. Fundamental studies targeted questions related to controlling surface assembly and interfacial chemistry details

NASA Tech Briefs, June 1993

Topics include: Imaging Technology: Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

Distributed Fiber Ultrasonic Sensor and Pattern Recognition Analytics

Ultrasound interrogation and structural health monitoring technologies have found a wide array of applications in the health care, aerospace, automobile, and energy sectors. To achieve high spatial resolution, large array electrical transducers have been used in these applications to harness sufficient data for both monitoring and diagnoses. Electronic-based sensors have been the standard technology for ultrasonic detection, which are often expensive and cumbersome for use in large scale deployments. Fiber optical sensors have advantageous characteristics of smaller cross-sectional area, humidity-resistance, immunity to electromagnetic interference, as well as compatibility with telemetry and telecommunications applications, which make them attractive alternatives for use as ultrasonic sensors. A unique trait of fiber sensors is its ability to perform distributed acoustic measurements to achieve high spatial resolution detection using a single fiber. Using ultrafast laser direct-writing techniques, nano-reflectors can be induced inside fiber cores to drastically improve the signal-to-noise ratio of distributed fiber sensors. This dissertation explores the applications of laser-fabricated nano-reflectors in optical fiber cores for both multi-point intrinsic Fabry–Perot (FP) interferometer sensors and a distributed phase-sensitive optical time-domain reflectometry (φ-OTDR) to be used in ultrasound detection. Multi-point intrinsic FP interferometer was based on swept-frequency interferometry with optoelectronic phase-locked loop that interrogated cascaded FP cavities to obtain ultrasound patterns. The ultrasound was demodulated through reassigned short time Fourier transform incorporating with maximum-energy ridges tracking. With tens of centimeters cavity length, this approach achieved 20kHz ultrasound detection that was finesse-insensitive, noise-free, high-sensitivity and multiplex-scalability. The use of φ-OTDR with enhanced Rayleigh backscattering compensated the deficiencies of low inherent signal-to-noise ratio (SNR). The dynamic strain between two adjacent nano-reflectors was extracted by using 3×3 coupler demodulation within Michelson interferometer. With an improvement of over 35 dB SNR, this was adequate for the recognition of the subtle differences in signals, such as footstep of human locomotion and abnormal acoustic echoes from pipeline corrosion. With the help of artificial intelligence in pattern recognition, high accuracy of events’ identification can be achieved in perimeter security and structural health monitoring, with further potential that can be harnessed using unsurprised learning

Dynamical systems : control and stability

Proceedings of the 13th Conference „Dynamical Systems - Theory and Applications" summarize 164 and the Springer Proceedings summarize 60 best papers of university teachers and students, researchers and engineers from whole the world. The papers were chosen by the International Scientific Committee from 315 papers submitted to the conference. The reader thus obtains an overview of the recent developments of dynamical systems and can study the most progressive tendencies in this field of science

Engineering Dynamics and Life Sciences

From Preface: This is the fourteenth time when the conference “Dynamical Systems: Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the Committee of Mechanics of the Polish Academy of Sciences and Ministry of Science and Higher Education of Poland. It is a great pleasure that our invitation has been accepted by recording in the history of our conference number of people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcomed over 180 persons from 31 countries all over the world. They decided to share the results of their research and many years experiences in a discipline of dynamical systems by submitting many very interesting papers. This year, the DSTA Conference Proceedings were split into three volumes entitled “Dynamical Systems” with respective subtitles: Vibration, Control and Stability of Dynamical Systems; Mathematical and Numerical Aspects of Dynamical System Analysis and Engineering Dynamics and Life Sciences. Additionally, there will be also published two volumes of Springer Proceedings in Mathematics and Statistics entitled “Dynamical Systems in Theoretical Perspective” and “Dynamical Systems in Applications”

Exploring the impact of self-assembly pathways on the structures and properties of small-molecule gels

Gels based on low-molecular-weight gelators (LMWGs) often consist of highly extended sheets or fibrils, which fuse or intertwine to produce a sample-spanning network. The aim of this investigation was to gain insight into such hierarchical processes by characterising a variety of urea-based LMWGs, and modelling the impact of key structural features on the outcome of self-assembly. Self-assembly of bis(urea) LMWGs often produces chains of urea-urea hydrogen bonds known as α tape motifs. One series of bis(urea)s with a sterically hindered spacer vary greatly in their gelation abilities, and form single crystals comprising a diverse range of α tape networks. Molecular dynamics simulations suggest that gels arise when crystal growth is outcompeted by the spontaneous scrolling of isolated lamellar assemblies. Thus, gelation is mainly associated with species that self-assemble into asymmetric lamellae, which undergo scrolling due to the differing forces exerted by the upper and lower faces. Even small changes to a self-assembly pathway can dramatically alter the resulting material. Photoisomerisation of bis(urea)s with terminal salicylidene-aniline (anil) moieties requires that the surface imine groups of crystalline lamellae can freely rotate, and is inhibited when gelation or co-crystallisation results in a less optimal molecular arrangement. Likewise, the anion affinities and aggregate microstructures of five isomeric linear tris(urea)s depend strongly on their spacer configurations. Although these molecules are not effective LMWGs, more extended oligo(urea)s can deliver higher gelation capacities. Remarkably, one achiral pentakis(urea) self-assembles into amyloid-like braided helices that may be chirally enriched by a template material. In addition, the tris(urea) analogue of this compound can form interfacial “lilypad” metallogels under vapour-diffusion conditions, demonstrating a novel mode of self-assembly with potential applications in metal sequestration. Building on these results could lead to supramolecular material with more complex microstructures and stimuli-responsive functionalities, and aid our understanding of the hierarchical self-assembly processes observed in biological systems

Proceedings of the Scientific-Practical Conference "Research and Development - 2016"

talent management; sensor arrays; automatic speech recognition; dry separation technology; oil production; oil waste; laser technolog

Soft pneumatic actuators: a review of design, fabrication, modeling, sensing, control and applications

Soft robotics is a rapidly evolving field where robots are fabricated using highly deformable materials and usually follow a bioinspired design. Their high dexterity and safety make them ideal for applications such as gripping, locomotion, and biomedical devices, where the environment is highly dynamic and sensitive to physical interaction. Pneumatic actuation remains the dominant technology in soft robotics due to its low cost and mass, fast response time, and easy implementation. Given the significant number of publications in soft robotics over recent years, newcomers and even established researchers may have difficulty assessing the state of the art. To address this issue, this article summarizes the development of soft pneumatic actuators and robots up until the date of publication. The scope of this article includes the design, modeling, fabrication, actuation, characterization, sensing, control, and applications of soft robotic devices. In addition to a historical overview, there is a special emphasis on recent advances such as novel designs, differential simulators, analytical and numerical modeling methods, topology optimization, data-driven modeling and control methods, hardware control boards, and nonlinear estimation and control techniques. Finally, the capabilities and limitations of soft pneumatic actuators and robots are discussed and directions for future research are identified