260,485 research outputs found
Continuum free-energy formulation for a class of lattice Boltzmann multiphase models
No full textWe characterize theoretically the free energy of the so called 'Shan-Chen' model for non ideal fluid flows
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M-estimator, and D-optimality model construction using orthogonal forward regression
No full textThis correspondence introduces a new orthogonal forward regression (OFR) model identification algorithm using D-optimality for model structure selection and is based on an M-estimators of parameter estimates. M-estimator is a classical robust parameter estimation technique to tackle bad data conditions such as outliers. Computationally, The M-estimator can be derived using an iterative reweighted least squares (IRLS) algorithm. D-optimality is a model structure robustness criterion in experimental design to tackle ill-conditioning in model Structure. The orthogonal forward regression (OFR), often based on the modified Gram-Schmidt procedure, is an efficient method incorporating structure selection and parameter estimation simultaneously. The basic idea of the proposed approach is to incorporate an IRLS inner loop into the modified Gram-Schmidt procedure. In this manner, the OFR algorithm for parsimonious model structure determination is extended to bad data conditions with improved performance via the derivation of parameter M-estimators with inherent robustness to outliers. Numerical examples are included to demonstrate the effectiveness of the proposed algorithm
Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses
Full text linkFollowing an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied
INNOVATIVE PILLAR[6]ARENE-BASED STATIONARY PHASES FOR HIGH-RESOLUTION GAS CHROMATOGRAPHIC ANALYSES
No full textIn this work, the synthesis, fabrication, and characterization of new stationary phases based on pillar[6]arene derivative modified by long alkyl chains (P6A-C10) for high-resolution gas chromatographic (GC) analyses are reported. Pillar[n]arenes are a new class of macrocyclic hosts that can accommodate specific guests due to their highly symmetrical and rigid pillar architectures with π-electron rich cavities. Quantum chemistry calculations have been performed, showing a difference in non-covalent interactions with the P6A-C10 pillar framework, which leads to specific selectivity for aromatic compounds. The GC columns prepared with these innovative stationary phases exhibited a medium polarity, and good reproducibility for run-to-run, day-to-day, and column-to-column analyses [1], demonstrating great potential as new stationary phases in separation science. Furthermore, peculiar advantages are achieved if compared with the commercial HP-5, HP-35, DB-17, and PEG-20M columns, showing unmatched resolving capabilities toward chloroaniline, bromoaniline, iodoaniline, toluidine, and xylene isomers [2].
References:
1. Sun, T., Chen, R., Huang, Q., Ba, M., Cai, Z., Hu, S., Liu, X., Nardiello, D., & Quinto, M., ACS Appl. Mater. Interfaces 14 (2022) 56132−56142.
2. Sun, T., Chen, R., Huang, Q., Ba, M., Cai, Z., Chen, H., Qi, Y., Chen, H., Liu, X., Nardiello, D., & Quinto, M., Anal. Chim. Acta 1251 (2023) 340979
Dung-chen(s) tibetanas
No full textLas dung-chen(s) son ejecutadas siempre en pares por monjes lamaístas durante distintos tipos de ceremonias y procesiones. Debido a su gran longitud (puede alcanzar los 4,50 m), en la primera ocasión se apoya el pabellón en el suelo o sobre un soporte de madera; en la segunda es sostenido sobre el hombro de un monje.
Cada una de las trompetas consta de un tubo cónico de cobre dividido en tres secciones que encajan a manera de telescopioEnd-blown natural trumpets. Both trumpets are made of a conical tube of red copper divided into three sections which assemble like a telescope.
Dung chen (s) are always played by two lamaist monks during different kinds of ceremonies and processions. Owing to its extreme length (it can reach 4,50 m.) during the ceremonies the bell is placed on the floor or on a wooden stand, while during processions the monk's shoulder supports it.Museo de Instrumentos Musicales Dr. Emilio Azzarin
Saussurea bhutanensis Y. S. Chen 2014, sp. nov.
No full text5. Saussurea bhutanensis Y. S. Chen, sp. nov. (Fig. 5, 9A & 9B) Type:— CHINA. Xizang: Yadong, Pagri, mountains between border of China and Bhutan, 27°37’ N, 89°07’ E, sandy meadows, 4870 m, 25 August 2013, FLPH Tibet Exped.13-2131 (holotype PE; isotypes PE). Herbs 1–4 cm tall, perennial, stemless, caespitose. Caudex 2–3 cm in diam., usually much branched. Rosette leaves sessile, linear, 10–25 × 1–1.5 mm, abaxially greyish white and densely tomentose-sericeous, adaxially green, shiny, and glabrous, base enlarged, sheathing, and white villous, margin entire and revolute, apex acute. Uppermost leaves merging into phyllaries, supporting capitula. Capitula solitary, in center of leaf rosette or terminal on stem, sessile, concealed by villous hairs. Involucre campanulate, 1–1.6 cm in diam. Phyllaries in ca. 6 rows, apex acuminate to caudate; outer phyllaries narrowly ovate-triangular, 14–16 × 3–4 mm, basal part dark green, apical part greenish, sparsely villous, and reflexed; middle and inner phyllaries narrowly ovate-triangular to narrowly elliptic-linear, 11–13 × ca. 2 mm, basal part pale yellow, apical part blackish purple, villous, and reflexed. Receptacle bristles very few, 1–2 mm long. Corolla purplish, 1.3–1.5 cm long, tube 7–8 mm long, limb 6.5–8 mm long, lobes 3.5–4 mm long. Achene dark brown, conic, ca. 3 mm long, glabrous. Pappus in 2 rows; outer bristles white, 2–3 mm long, scabrid; inner bristles pale brown, 9–10 mm long, plumose. Distribution and habitat: — Saussurea bhutanensis occurs in northern Bhutan and adjacent border of Yadong, Xizang, China. It grows on alpine sandy meadows (including Saussurea, Aster, Primula, Arenaria, Gentiana, Swertia, Cyananthus, Saxifraga and Delphinium species), alpine scree or limestones at altitudes of 4500–4900 m. Phenology:—Flowering and fruiting from August to October. Etymology: —The specific epithet is derived from its main distribution area, Bhutan. Additional specimens examined (paratypes): — BHUTAN. [Bumthang district]: Tolegang, Tsampa, steep open hillside, 4720 m, 2 October 1949, F . Ludlow, G. Sherriff & J. H. Hicks 19784 (BM, E); [Wangdi district]: Wangdue-Phodrang, Thampe La, limestone, 27°43’ N, 90°18’ E, 4500–4600 m, 28 September 2000, G. & S . Miehe 00-421-01 (E). Discussion:— Saussurea bhutanensis belongs to S. subgen. Saussurea sect. Lagurostemon on account of its leaf blade being linear, entire, grasslike, and the capitula solitary, 1–1.6 cm in diameter. Grierson & Springate (2001) reported one specimen from Bhutan (F. Ludlow, G. Sherriff & J. H. Hicks 19784) that is related to Saussurea columnaris Handel-Mazzetti (1937: 652), but they noted this specimen is different from the typical S. columnaris in its receptacle naked, achene glandular-stipitate above and habit usually stemless. This kind of specimen was also found from the Tibetean border with Bhutan (FLPH Tibet Exped.13-2131) by the present author in 2013. But the present author found its receptacle is not entirely naked but with few short bristles 1–2 mm long, achenes glabrous, leaves 1–2.5 cm long, phyllaries usually narrower and apex acuminate, capitula concealed by dense villous hairs. Typical specimens of S. columnaris from Yunnan are different in the receptacle bristles ca. 7 mm long and plants usually stemmed, leaves 2–7 cm long, phyllaries usually broader and apex acute, capitula not concealed by villous hairs. Saussurea bhutanensis is also similar to S. durgae Jeffrey & Srivastava (1997: 235) in its caespitose habit and linear grassy leaves, but S. bhutanensis differs in its leaves adaxially green, shiny, and glabrous, capitula concealed by villous hairs, and corolla purplish, whereas S. durgae differs in its leaves densely clothed with greyish white wooly hairs on both surfaces, capitula not concealed by villous hairs, and corolla pink. A comparison of S. bhutanensis, S. columnaris and S. durgae is given in Table 5.Published as part of Chen, You-Sheng, 2014, Six new species of Saussurea (Asteraceae) from eastern Himalaya, pp. 191-206 in Phytotaxa 177 (4) on page 199, DOI: 10.11646/phytotaxa.177.4.1, http://zenodo.org/record/514474
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