1,116 research outputs found
Sampling Plans for Control-Inspection Schemes Under Independent and Dependent Sampling Designs With Applications to Photovoltaics
The evaluation of produced items at the time of delivery is, in practice,
usually amended by at least one inspection at later time points. We extend the
methodology of acceptance sampling for variables for arbitrary unknown
distributions when additional sampling infor- mation is available to such
settings. Based on appropriate approximations of the operating characteristic,
we derive new acceptance sampling plans that control the overall operating
characteristic. The results cover the case of independent sampling as well as
the case of dependent sampling. In particular, we study a modified panel
sampling design and the case of spatial batch sampling. The latter is advisable
in photovoltaic field monitoring studies, since it allows to detect and analyze
local clusters of degraded or damaged modules. Some finite sample properties
are examined by a simulation study, focusing on the accuracy of estimation
Steric effect in O<sup>+</sup>/H<sub>2</sub> and H<sup>+</sup>/H<sub>2</sub>O collisions - Charge transfer in H<sub>2</sub>O<sup>+</sup> and H<sub>3</sub>O<sup>+</sup> collision intermediate systems
Oral health-related impact profile of patients treated with fixed, removable, and telescopic dental prostheses in student courses — a prospective bicenter clinical trial
Objectives!#!To analyze the oral health-related impact profile in patients treated with three different types of dental prosthesis in student courses.!##!Materials and methods!#!This prospective bicenter clinical trial was conducted with 151 patients being treated with fixed (n = 70), removable (n = 61), or telescopic dental prostheses (n = 20) in clinical student courses of two German universities from October 2018 to October 2019. All patients completed three standardized German versions of the Oral Health Impact Profile (OHIP-G49/53) before prosthetic treatment (T0), at control after 1 week (T1), and after 3 months (T2), divided into five dimensions: (a) appearance, (b) oral function, (c) psychosocial impact, (d) linguistic limitations, and (e) orofacial pain. Data were analyzed with Kolmogorov-Smirnov, Wilcoxon signed-rank, Kruskal-Wallis, Mann-Whitney, and Cronbach's alpha tests.!##!Results!#!Within T0-T1 and T0-T2, greater improvements were determined for removable compared with fixed dental prostheses for the dimensions' oral function (p ≤ 0.014), linguistic limitations (p ≤ 0.016), and appearance (p ≤ 0.003). No significant differences were found between fixed and telescopic dental prostheses (p ≥ 0.104) or between removable (partial dental prosthesis with clasps and complete dental prosthesis) and telescopic dental prostheses (p ≥ 0.100). Within T1-T2, a significant improvement in orofacial pain could be determined (p = 0.007).!##!Conclusions!#!Restorations presented an improvement in oral health-related quality of life. Removable dental prostheses showed better improvement than fixed ones in various dimensions.!##!Clinical relevance!#!Knowledge about the influence of oral health-related quality of life on the three different types of prosthesis used in student courses can be of decisive help in dental consultations
Non-abelian Harmonic Oscillators and Chiral Theories
We show that a large class of physical theories which has been under
intensive investigation recently, share the same geometric features in their
Hamiltonian formulation. These dynamical systems range from harmonic
oscillations to WZW-like models and to the KdV dynamics on . To the
same class belong also the Hamiltonian systems on groups of maps.
The common feature of these models are the 'chiral' equations of motion
allowing for so-called chiral decomposition of the phase space.Comment: 1
Measuring velocity of sound with nuclear resonant inelastic x-ray scattering
Nuclear resonant inelastic x-ray scattering is used to measure the projected
partial phonon density of states of materials. A relationship is derived
between the low-energy part of this frequency distribution function and the
sound velocity of materials. Our derivation is valid for harmonic solids with
Debye-like low-frequency dynamics. This method of sound velocity determination
is applied to elemental, composite, and impurity samples which are
representative of a wide variety of both crystalline and noncrystalline
materials. Advantages and limitations of this method are elucidated
A geometric approach to time evolution operators of Lie quantum systems
Lie systems in Quantum Mechanics are studied from a geometric point of view.
In particular, we develop methods to obtain time evolution operators of
time-dependent Schrodinger equations of Lie type and we show how these methods
explain certain ad hoc methods used in previous papers in order to obtain exact
solutions. Finally, several instances of time-dependent quadratic Hamiltonian
are solved.Comment: Accepted for publication in the International Journal of Theoretical
Physic
Impact of polishing system on surface roughness of different ceramic surfaces after various pretreatments and bracket debonding
Objective
Evaluating various polishing methods after bracket debonding and excessive attachment material removal for different ceramics and pretreatments.
Material and methods
Zirconia (ZrO2), leucite (LEU) and lithium disilicate (LiSi) specimens were pretreated with a) silica coated alumina particles (CoJet); LEU and LiSi additionally with b) hydrofluoric acid (HF), c) Monobond Etch&Prime (MEP), d) silicium carbide grinder (SiC) before bracket bonding, shearing off, ARI evaluation, excessive attachment material removal and polishing with i) Sof-Lex Discs (Soflex), ii) polishing paste (Paste), iii) polishing set (Set). Before/after polishing surface roughness (Ra) was measured with a profilometer. Martens hardness parameter were also assessed.
Results
Irrespective of pretreatment Ra of LEU increased the most, followed by LiSi and ZrO2 (p < 0.001, SiC: p = 0.012), in accordance with the measured Martens hardness parameter. CoJet/SiC caused greater roughness as HF/MEP (p < 0.001). The ZrO2 surface was rougher after polishing with Paste/Set (p < 0.001; p = 0.047). Ra improved in the LEU/CoJet, LEU/SiC and LiSi/SiC groups with Soflex/Set (p < 0.001), in the LiSi/CoJet and LEU/HF groups by Soflex (p = 0.003, p < 0.001) and worsened by Paste (p = 0.017, p < 0.001). Polishing of HF or MEP pretreated LiSi with Set increased Ra (p = 0.001, p < 0.001), so did Paste in the LEU/MEP group (p < 0.001).
Conclusions
Paste couldn’t improve the surfaces. Soflex was the only method decreasing Ra on rough surfaces and not causing roughness worsening. Polishing of LEU/LiSi after MEP, LEU after HF pretreatment doesn´t seem to have any benefit.
Clinical Relevance
To avoid long-term damage to ceramic restorations, special attention should be paid to the polishing method after orthodontic treatment
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