4,796 research outputs found
A Hybrid Position Feedback Controller for Bistable Structures
Bistability is the property of structures showing the ability to attain two statically stable states. Due to dynamic and static advantages such as no energy demand at stable positions and providing higher deflections compared to a monostable structure, bistability may be appealing in control surface design for aircraft structures and load alleviation for wind turbine blades. The dynamics of bistable structures is nonlinear because of the snap-through occurring during the cross-well oscillation between two stable states. A new control strategy called hybrid position feedback control is developed based on the conventional positive position control to exploit linear dynamics of bistable structures around stable equilibrium positions.
In this thesis, complementary stability, performance and energy analysis of bistable structures controlled by the hybrid controller are investigated using numerical time domain and frequency methods. The stability regions, energy variance by parameters, and the operational regions providing state transition are determined. As a result of the analyses, two alternative design options are proposed and necessary stability regions are indicated.
In addition, experimental analysis is conducted on an unsymmetric cross-ply bistable composite plate to show the feasibility of the hybrid control strategy. Various analyses such as stability and energy consumption are performed
Functional equations from generating functions: a novel approach to deriving identities for the Bernstein basis functions
The main aim of this paper is to provide a novel approach to deriving
identities for the Bernstein polynomials using functional equations. We derive
various functional equations and differential equations using generating
functions. Applying these equations, we give new proofs for some standard
identities for the Bernstein basis functions, including formulas for sums,
alternating sums, recursion, subdivision, degree raising, differentiation and a
formula for the monomials in terms of the Bernstein basis functions. We also
derive many new identities for the Bernstein basis functions based on this
approach. Moreover, by applying the Laplace transform to the generating
functions for the Bernstein basis functions, we obtain some interesting series
representations for the Bernstein basis functions.Comment: 1
Bernoulli type polynomials on Umbral Algebra
The aim of this paper is to investigate generating functions for modification
of the Milne-Thomson's polynomials, which are related to the Bernoulli
polynomials and the Hermite polynomials. By applying the Umbral algebra to
these generating functions, we provide to deriving identities for these
polynomials
Static and vibration analysis of functionally graded beams using refined shear deformation theory
Static and vibration analysis of functionally graded beams using refined shear deformation theory is presented. The developed theory, which does not require shear correction factor, accounts for shear deformation effect and coupling coming from the material anisotropy. Governing equations of motion are derived from the Hamilton's principle. The resulting coupling is referred to as triply coupled axial-flexural response. A two-noded Hermite-cubic element with five degree-of-freedom per node is developed to solve the problem. Numerical results are obtained for functionally graded beams with simply-supported, cantilever-free and clamped-clamped boundary conditions to investigate effects of the power-law exponent and modulus ratio on the displacements, natural frequencies and corresponding mode shapes
Overcoming scarring in the urethra: Challenges for tissue engineering.
Urethral stricture disease is increasingly common occurring in about 1% of males over the age of 55. The stricture tissue is rich in myofibroblasts and multi-nucleated giant cells which are thought to be related to stricture formation and collagen synthesis. An increase in collagen is associated with the loss of the normal vasculature of the normal urethra. The actual incidence differs based on worldwide populations, geography, and income. The stricture aetiology, location, length and patient's age and comorbidity are important in deciding the course of treatment. In this review we aim to summarise the existing knowledge of the aetiology of urethral strictures, review current treatment regimens, and present the challenges of using tissue-engineered buccal mucosa (TEBM) to repair scarring of the urethra. In asking this question we are also mindful that recurrent fibrosis occurs in other tissues-how can we learn from these other pathologies
Special Functions Related to Dedekind Type DC-Sums and their Applications
In this paper we construct trigonometric functions of the sum T_{p}(h,k),
which is called Dedekind type DC-(Dahee and Changhee) sums. We establish
analytic properties of this sum. We find trigonometric representations of this
sum. We prove reciprocity theorem of this sums. Furthermore, we obtain
relations between the Clausen functions, Polylogarithm function, Hurwitz zeta
function, generalized Lambert series (G-series), Hardy-Berndt sums and the sum
T_{p}(h,k). We also give some applications related to these sums and functions
Reliability and validity of the Turkish translation of the beliefs about medicines questionnaire (BMQ-T) in patients with Behçet’s disease
OBJECTIVES: The aim of this study was to evaluate the reliability and validity of the Turkish translation of the Beliefs about Medicines Questionnaire (BMQ-T, ©Prof. Rob Horne) for patients with Behçet's disease. METHODS: This methodological study enrolled a sample of 125 patients. The scale was adapted to Turkish through a process including translation, comparison with versions in other languages, back translation, and pretesting. Construct validity was evaluated by factor analysis. Medication adherence evaluated as poor, moderate and good according to the Morisky Medication Adherence Scale (MMAS). BMQ-T scores compared along medication adherence status groups. RESULTS: In our study, as in the original scale, the factor analysis confirmed that the BMQ-T had a four-factor structure explaining 54.73% of the total variance. The BMQ-T had acceptable internal consistency (Cronbach's alpha coefficient: Specific Necessity=.812; Specific Concerns=.672; General Harm=.677; General Overuse=.656), adequate test-retest reliability (intraclass correlation coefficients: Specific Necessity=.715; Specific Concerns=.680; General Harm=.678; General Overuse=.327). Specific Necessity and Specific Concerns scores were significantly different between medication adherence status groups. CONCLUSIONS: The psychometric properties of the BMQ-T were consistent with those reported in the original study. The BMQ-T was found to be a valid and reliable tool for evaluating beliefs about medicines in patients with Behçet's disease
Corporate governance structure and climate‐related financial disclosure: conventional banks versus Islamic banks
This paper examines whether the different corporate governance structures of conventional banks (CBs) and Islamic banks (IBs) have varying effects on their respective climate-related disclosure (CRD). Employing a unique dataset of CBs and IBs' CRD and corporate governance structures for the period of 2016–2019, we found that their respective corporate governance structures did indeed affect their CRD in different ways. Our findings suggest that CBs disclose more climate-related information than IBs because IBs focus on Sharia compliance which does not emphasise the protection of the environment, while CBs may be more responsive to shareholders' and stakeholders' demands on climate and environment. These effects were stronger with the quality of governance, that is, CBs disclose more climate-related information with the governance quality, while IBs disclose even less when their governance quality increases. The findings of this study have important implications for climate change, especially the Paris Accord and The 26th Meeting of the Conference of Parties (COP26). There are also policy implications for sustainable financial markets and the financial services sector
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