A study of low-cost reliable actuators for light aircraft. Part A: Chapters 1-8

An analysis involving electro-mechanical, electro-pneumatic, and electro-hydraulic actuators was performed to study which are compatible for use in the primary and secondary flight controls of a single engine light aircraft. Actuator characteristics under investigation include cost, reliability, weight, force, volumetric requirements, power requirements, response characteristics and heat accumulation characteristics. The basic types of actuators were compared for performance characteristics in positioning a control surface model and then were mathematically evaluated in an aircraft to get the closed loop dynamic response characteristics. Conclusions were made as to the suitability of each actuator type for use in an aircraft

A study of low-cost reliable actuators for light aircraft. Part B: Appendices

Computer programs written in FORTRAN are given for time response calculations on pneumatic and linear hydraulic actuators. The programs are self-explanatory with comment statements. Program output is also included

Operando spectroscopy for resin curing

Coatings and paint are important in our daily lives, both for aesthetic as well as protective purposes. In this thesis, the hardening of a particular coating material based on a mixture of bismethacrylate and styrene, which is used to protect steel from corrosion, for example, from acidic liquids. The transition to sustainable and benign coatings is an important stimulus for this research, considering both human and animal exposure to components, as well as environmental impact. Specifically, the search for an alternative cobalt catalyst was the driving force for the research described here. Making this apparently simple step turns out to be more difficult than simply substituting ingredients. A deeper understanding of how the components work is essential. The focus of this thesis rests on understanding the process of curing and how factors affect the kinetics of the reactions involved with an emphasis on the spectroscopic techniques used to do this.The data discussed demonstrate how ineffective simply changing (screening) catalysts for curing is, and that a reformulation of the current resins needs to be made to achieve coatings of equal quality to those used currently. Operando spectroscopy allows us to follow curing in real time, which is essential to make rapid and quantitative choices in the composition of the initiator system

Structure and function of lytic polysaccharide monooxygenases (LPMOS)and other redox enzymes involved in biomass processing

The discovery of Lytic Polysaccharide Monooxygenases (LPMOs) has revolutionized our understanding of biomass conversion in Nature and has been instrumental for the development of economically sustainable lignocellulose biorefineries. LPMOs are mono-copper redox enzymes that attack the most recalcitrant parts of biopolymers such as crystalline cellulose and chitin. LPMOs employ the power of redox chemistry to cleave glycosidic bonds that are not easily cleaved by hydrolytic enzymes. By doing so, they make the substrate more tractable to the action of canonical enzymes such as endo- and exo-cellulases. LPMOs are abundant in Nature, for example in the secretomes of wood-decaying fungi. Despite their importance in both Nature and the biorefinery, several aspects of these intriguing enzymes remain unclear. The catalytic mechanism of LPMOs is of particular importance because the enzymes display a unique active site architecture that is employed to catalyze a challenging chemical reaction on a substrate that is embedded in a crystalline lattice. Deeper insight into this mechanism may have wide-reaching consequences, not only for biomass processing but also, perhaps, in developing enzymatic or other catalytic systems for difficult reactions, such as controlled oxidation of methane and other alkanes. Using a variety of experimental approaches, we are studying LPMO function, addressing issues such as the structural basis of oxidative regio-selectivity and substrate specificity, routes and mechanisms for electron delivery, the roles of appended carbohydrate-binding domains, and the determinants of catalytic activity and stability. Knowledge gained from these fundamental studies is being used to optimize biomass conversion processes, whereas translation of this knowledge to other fields is also being explored. In this presentation, I will review recent work in the field and present our latest results. Special attention will be paid to recent research in our group that has led to the proposal that LPMOs may not be true monooxygenases. Based on our recent results, we have proposed that hydrogen peroxide, rather than molecular oxygen, is the preferred co-substrate of LPMOs. While this paradigm-shattering proposal may not yet have found wide acceptance in the field, we have already demonstrated that the controlled administration of hydrogen peroxide during biomass degradation by LPMO-containing commercial cellulolytic enzyme cocktails leads to drastically improved LPMO activity and more efficient saccharification. These recent findings also shed new light on the interplay between LPMOs and other redox enzymes in the secretomes of biomass degrading microorganisms

Recovering Homography from Camera Captured Documents using Convolutional Neural Networks

Removing perspective distortion from hand held camera captured document images is one of the primitive tasks in document analysis, but unfortunately, no such method exists that can reliably remove the perspective distortion from document images automatically. In this paper, we propose a convolutional neural network based method for recovering homography from hand-held camera captured documents. Our proposed method works independent of document's underlying content and is trained end-to-end in a fully automatic way. Specifically, this paper makes following three contributions: Firstly, we introduce a large scale synthetic dataset for recovering homography from documents images captured under different geometric and photometric transformations; secondly, we show that a generic convolutional neural network based architecture can be successfully used for regressing the corners positions of documents captured under wild settings; thirdly, we show that L1 loss can be reliably used for corners regression. Our proposed method gives state-of-the-art performance on the tested datasets, and has potential to become an integral part of document analysis pipeline.Comment: 10 pages, 8 figure

The pyrroloquinoline-quinone (PQQ)-dependent quinohemoprotein pyranose dehydrogenase from Coprinopsis cinerea (CcPDH), belonging to the AA12 family, drives lytic polysaccharide monooxygenase (LPMO) action

Fungi secrete a set of glycoside hydrolases and oxidoreductases, including lytic polysaccharide monooxygenases (LPMOs), for the degradation of plant polysaccharides. LPMOs accelerate the decomposition of cellulose by cellulases by catalyzing the oxidative cleavage of glycosidic bonds after activation by an external electron donor (1-3). LPMOs procure electrons from non-enzymatic electron donors, such as ascorbic acid, lignin and other plant biomass-derived phenols (1-3), or they can be activated by flavin-dependent oxidoreductases, directly or through plant-derived diphenols and quinones acting as redox mediators (3-7). Cellobiose dehydrogenase, in particular, efficiently transfers electrons from its AA3_1 dehydrogenase domain to LPMOs via an appended AA8 cytochrome domain (7). Here we show that LPMOs can be activated by a quinohemoprotein, namely the pyrroloquinoline-quinone (PQQ)-dependent pyranose dehydrogenase CcPDH from Coprinopsis cinerea, the founding member of the recently discovered AA12 family (8). CcPDH has a domain composition similar to that of cellobiose dehydrogenases (CDHs) but contains a central catalytic AA12 dehydrogenase domain, rather than an AA3_1 domain. We have studied the ability of full length CcPDH and its truncated variants to drive catalysis by two Neurospora crassa LPMOs, NcLPMO9F and NcLPMO9C. Our study shows that both the AA8 and CBM1 domains of CcPDH have a positive effect on the CcPDH-NcLPMO system. The interplay between the PDH and LPMOs seemed also to depend on whether the LPMO contained a CBM. Unlike the single dehydrogenase domain of MtCDH from Myriococcum thermophylum, the AA12 dehydrogenase domain of CcPDH could drive the LPMO reaction, which is due to the non-covalently bound PQQ co-factor acting as a diphenol/quinone redox mediator. CcPDH does not oxidize cello-oligosaccharides, which makes this enzyme a useful tool in future studies of LPMOs and redox enzyme systems involved in cellulose degradation. References: [1] Vaaje-Kolstad, G. et al. (2010) Science 330, 219-222. [2] Hemsworth, G. R., et al. (2015) Trends Biotechnol 33:747-761. [3] Kracher, D. et al. (2016) Science 352, 1098-1101. [4] Westereng, B. et al. (2015) Sci Rep 5:18561. [5] Langston, J.A. et al. (2011) Appl Environ Microbiol 77:7007-7015. [6] Garajova, S. et al. (2016) Sci Rep 6:28276. [7] Tan, T.C. et al. (2015) Nat Commun 6:7542. [8] Takeda, K. et al. (2015) PLoS One 10:e0115722