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Search Results: 1 - 10 of 315395 matches for " J. Gao "
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Computational Analysis of Gas Phase Mixing in a Co-Fired Burner with Two Different Designs  [PDF]
J. Iqbal, S. Gao
Journal of Power and Energy Engineering (JPEE) , 2015, DOI: 10.4236/jpee.2015.34025
Abstract:

The study of swirling jet combustor for biomass coal co-firing is of great interest for energy industry. The biomass co-firing can serve as a NOx reduction method as well as the better use of renewable energy source. Large eddy simulation (LES) and RANS modelling have been performed with two different burner designs. Usually pulverized coal-biomass mixture enters the furnace along with primary air through primary pipe, and the secondary pipe provides necessary air and mixing for combustion. The improved model has three passages including primary, secondary and middle passage for swirling. The simulations on two geometries have been compared, and the aim is to design a better and improved burner model for better pre-combustion mixing in the biomass co- fired furnace. The results from two-way and three-way geometry have been compared with each other as well as with the results from the furnace model used by Apte and Mahesh [8].

Exact Distributions of Waiting Time Problems of Mixed Frequencies and Runs in Markov Dependent Trials  [PDF]
Bruce J. Chaderjian, Morteza Ebneshahrashoob, Tangan Gao
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.311234
Abstract: We study waiting time problems for first-order Markov dependent trials via conditional probability generating functions. Our models involve α frequency cells and β run cells with prescribed quotas and an additional γ slack cells without quotas. For any given and , in our Model I we determine the waiting time until at least frequency cells and at least run cells reach their quotas. For any given τα + β, in our Model II we determine the waiting time until τ cells reach their quotas. Computer algorithms are developed to calculate the distributions, expectations and standard deviations of the waiting time random variables of the two models. Numerical results demonstrate the efficiency of the algorithms.
Kinetics Study on Photocatalytic Degradation of Methyl Orange Catalyzed by Sea Urchin-Like Cu2O  [PDF]
R. J. Gao, T. Ding, X. J. Duan
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.46005
Abstract:
Sea urchin-like cuprous oxide with hollow glass microsphere as core was prepared using sodium sulfite as the reducing agent and sodium acetate-acetic acid as buffer solution in copper sulfate solution. Methyl orange was selected as degradation target for photocatalytic experiments. The photocatalytic activities were investigated by visible spectro- photometer. Photocatalytic kinetics parameters were studied by the Langmuir-Hinshelwood model and Arrhenius formula. It was observed that the sea urchin-like morphology dramatically improved the photocatalytic activity of cuprous oxide. The photo-degradation belongs to the first-order reaction and the maximum degradation rate could reach 94.37%. The activation energy and pre-exponential factor are 41.18 KJ·mol-1 and 1.07 × 106, respectively. After seven times recycling, the sample still showed high photo-catalytic efficiency and stability.
A novel phase shift technique in shearography for NDT
Liu Z.,Gao J.
EPJ Web of Conferences , 2010, DOI: 10.1051/epjconf/20100633003
Abstract: Digital shearography (DS) is a whole-field non-contacting optical method for nondestructive testing (NDT) of subsurface flaws and strain measurement. In this paper, we describe a novel phaseshifting technique in DS for nondestructive evaluation (NDE) and NDT of quasi dynamic behaviour of objects subject to varying loads. A Wollaston lens, a precise wave plate device and a polariser are employed to introduce constant phase differences between two shearing wavefronts. The wave plate device is in front of the polariser, which has a transmissive wavefront distortion of less than 1/8 wavelength. Phase difference can be adjusted by rotating the polariser. The rotation for angle adjusting can be easily carried out according to the requirement of the phase shifting. In this technique, the phase shifting is performed only on the static images of the object before deformation or loading. By setting the angle of the polariser to 0o, -60o and 60o, three speckle patterns with the defined phase differences are captured, and are referred to as initial speckle patterns I1,0, I1,-60 and I1,60. Afterwards, the polariser is reset to 0o before loading. The speckle pattern I0 is treated as a base pattern, and will be subtracted from the subsequent speckle patterns which are captured in the quasi dynamic deformation process. During the quasi dynamic deformation process, the optical path and the entire optical set-up will be kept unchanged, and a series of speckle patterns (Im,0, m=2,3,…..) which carry the deformation information will be quickly captured. In the meantime, fast image subtractions will be performed. The speckle fringes (Im,0 -I1,0) will be displayed in real-time. In detailed post-processing, phase of differences method (PDM) [1] is used to extract phase information from the speckle images Im,0 -I1,0, I1,0, I1,-60 and I1,60. Specifically, when a three phase step technique is employed, the phase of the fringe pattern (Im,0-I1,0) can be calculated from (Im,0 -I1,0)+ I1,0 -I1,-60, (Im,0 -I1,0), and (Im,0 -I1,0)+ I1,0 -I1,60. Because this temporal phase shifting is not performed in the deformation process, the technique is suitable for NDT and NDE of quasi dynamic deformation behaviour of an object. The technique only requires three speckle patterns with phase differences prior to the object deformation. When a varying or quasi dynamic load is applied on the object, no physical phase shifting is needed to be conducted when sequential speckle patterns are recorded by a digital camera during the deformation process. Compared with the (5, n) temporal phase shifting tech
An Analysis of Phase Transition in NK Landscapes
J. Culberson,Y. Gao
Computer Science , 2011, DOI: 10.1613/jair.1081
Abstract: In this paper, we analyze the decision version of the NK landscape model from the perspective of threshold phenomena and phase transitions under two random distributions, the uniform probability model and the fixed ratio model. For the uniform probability model, we prove that the phase transition is easy in the sense that there is a polynomial algorithm that can solve a random instance of the problem with the probability asymptotic to 1 as the problem size tends to infinity. For the fixed ratio model, we establish several upper bounds for the solubility threshold, and prove that random instances with parameters above these upper bounds can be solved polynomially. This, together with our empirical study for random instances generated below and in the phase transition region, suggests that the phase transition of the fixed ratio model is also easy.
Consistency and Random Constraint Satisfaction Models
J. Culberson,Y. Gao
Computer Science , 2011, DOI: 10.1613/jair.2155
Abstract: In this paper, we study the possibility of designing non-trivial random CSP models by exploiting the intrinsic connection between structures and typical-case hardness. We show that constraint consistency, a notion that has been developed to improve the efficiency of CSP algorithms, is in fact the key to the design of random CSP models that have interesting phase transition behavior and guaranteed exponential resolution complexity without putting much restriction on the parameter of constraint tightness or the domain size of the problem. We propose a very flexible framework for constructing problem instances withinteresting behavior and develop a variety of concrete methods to construct specific random CSP models that enforce different levels of constraint consistency. A series of experimental studies with interesting observations are carried out to illustrate the effectiveness of introducing structural elements in random instances, to verify the robustness of our proposal, and to investigate features of some specific models based on our framework that are highly related to the behavior of backtracking search algorithms.
The Quantized Characterization of Cooked Rice Hardness and Research on the Automatic Measurement Technology  [PDF]
N. Jiang, Y. Gao, J.P. Zhou, L.Q. Gao, J.H. Zhou, Q.G. Dai
Engineering (ENG) , 2010, DOI: 10.4236/eng.2010.22013
Abstract: The hardness of cooked rice is one of the most important criteria which determine the rice quality. The commonly used near-infrared reflectance (NIR) method is still in argument due to its indirectness and possible error. In this paper, a mechanical method was proposed and its principle, automation, components and operative reliability were evaluated and compared with the NIR method. The results showed that the mechanical testing method can accurately detect the rice quality and were consistent with the NIR testing data. This new mechanical method can be effectively used in rice quality testing and branding with the advantage of simplicity, accuracy and reliability.
Caregiver assessment of patients with advanced cancer: concordance with patients, effect of burden and positivity
Irene J Higginson, Wei Gao
Health and Quality of Life Outcomes , 2008, DOI: 10.1186/1477-7525-6-42
Abstract: A total of 64 advanced cancer patient and informal caregiver dyads were recruited from regional palliative care services and interviewed. Patients' outcomes were assessed with both the patient and the caregiver version of the Palliative Outcome Scale (POS); caregiver burden and positivity were collected with the Zarit Burden interview (ZBI) and three questions on achievements and relationships. The agreement between patient- and caregiver-rated POS was measured with weighted kappa statistics. The roles of caregiver burden and positivity in POS agreement were studied with logistic regression controlling for potential confounders; adjusted odds ratios were estimated from the models.Agreement was substantial for pain, moderate for four items, fair for three items and slight for two items. Compared with patients self-ratings, caregivers described more problems with information given and sharing feelings and were less likely to assess the patient felt their life was worthwhile or felt good about themselves. Disagreement for three POS item ratings was significantly associated with higher caregiver burden: "feeling anxious"(OR: 4.5; 95%CI: 1.3 to 15.6), "life worthwhile"(OR: 12.4; 95%CI: 2.9 to 54.3) and "felt good" (OR: 7.7; 95%CI: 2.0 to 29.6). Caregivers with higher positivity scores were more likely to agree patients' rating of "felt good"(OR: 0.3; 95%CI: 0.1–0.9) but at increased risk of disagreeing about patient's "practical problems"(OR: 4.2; 95%CI: 1.1 to 16.6).Caregiver burden and positivity affect their assessments, especially of psychological patient domains and whether patients assess their life as worthwhile. Awareness of this might help clinicians and researchers better interpret caregiver assessments.In advanced cancer the assessment of pain, symptoms and domains relevant to quality of life are an essential component of quality care. In clinical practice, the oncologist assesses the symptoms and factors affecting quality of life in order to plan treatment. H
Fermentation and Hydrogen Metabolism Affect Uranium Reduction by Clostridia
Weimin Gao,Arokiasamy J. Francis
ISRN Biotechnology , 2013, DOI: 10.5402/2013/657160
Abstract:
Dislocation Nucleation and Pileup under a Wedge Contact at Nanoscale
Y. F. Gao,J. Lou
Journal of Nanomaterials , 2008, DOI: 10.1155/2008/380961
Abstract: Indentation responses of crystalline materials have been found to be radically different at micrometer and nanometer scales. The latter is usually thought to be controlled by the nucleation of dislocations. To explore this physical process, a dislocation mechanics study is performed to determine the conditions for the nucleation of a finite number of dislocations under a two-dimensional wedge indenter, using the Rice-Thomson nucleation criterion. The configurational force on the dislocation consists of the applied force, the image force, and the interaction force between dislocations. Dislocations reach equilibrium positions when the total driving force equals the effective Peierls stress, giving a set of nonlinear equations that can be solved using the Newton-Raphson method. When the apex angle of the wedge indenter increases, the critical contact size for dislocation nucleation increases rapidly, indicating that dislocation multiplication near a blunt wedge tip is extremely difficult. This geometric dependence agrees well with experimental findings.
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