Adaptive discontinuous finite element quadrature sets over an icosahedron for discrete ordinates method

The discrete ordinates(S N)method requires numerous angular unknowns to achieve the desired accu-racy for shielding calculations involving strong anisotropy.Our objective is to develop an angular adaptive algorithm in the S N method to automatically optimize the angular distribution and minimize angular discretization errors with lower expenses.The proposed method enables linear dis-continuous finite element quadrature sets over an icosahe-dron to vary their quadrature orders in a one-twentieth sphere so that fine resolutions can be applied to the angular domains that are important.An error estimation that operates in conjunction with the spherical harmonics method is developed to determine the locations where more refinement is required.The adaptive quadrature sets are applied to three duct problems,including the Kobayashi benchmarks and the IRI-TUB research reactor,which emphasize the ability of this method to resolve neutron streaming through ducts with voids.The results indicate that the performance of the adaptive method is more effi-cient than that of uniform quadrature sets for duct transport problems.Our adaptive method offers an appropriate placement of angular unknowns to accurately integrate angular fluxes while reducing the computational costs in terms of unknowns and run times.

Neutronic calculations of the China dual-functional lithium–lead test blanket module with the parallel discrete ordinates code Hydra

The China dual-functional lithium–lead test blanket module(DFLL-TBM) is a liquid Li Pb blanket concept developed by the Institute of Nuclear Energy Safety Technology of the Chinese Academy of Sciences for testing in ITER to validate relevant tritium breeding and shielding technologies. In this study, neutronic calculations of DFLL-TBM were carried out using a massively parallel three-dimensional transport code, Hydra, with the Fusion Evaluated Nuclear Data Library/MG. Hydra was developed by the Nuclear Engineering Computational Physics Lab based on the discrete ordinates method and has been devoted to neutronic analysis and shielding evaluation for nuclear facilities. An in-house Monte Carlo code(MCX) was employed to verify the discretized calculation model used by Hydra for the DFLL-TBM calculations. The results showed two key aspects:(1) In most material zones,Hydra solutions are in good agreement with the reference MCX results within 1%, and the maximal relative difference of the neutron flux is merely 3%, demonstrating the correctness of the calculation model;(2) while the current DFLL-TBM design meets the operation shielding requirement of ITER for 4 years, it does not satisfy the tritium self-sufficiency requirement. Compared to the two-step approach, Hydra produces higher accuracies as it does not rely on the homogenization technique during the calculation process. The parallel efficiency tests of Hydra using the DFLL-TBM model also showed that this code maintains a high parallel efficiency on O(100) processors and, as a result, is able to significantly improve computing performance through parallelization. Parameter studies have been carried out by varying the thickness of the beryllium armor layer and the tritium breeding zone to understand the influence of the beryllium layer and breeding zone thickness on tritium breeding performance. This establishes a foundation for further improvement in the tritium production performance of DFLL-TBM.

Vector Radiative Transfer in a Vertically Inhomogeneous Scattering and Emitting Atmosphere.PartⅠ:A New Discrete Ordinate Method

The original vector discrete ordinate radiative transfer(VDISORT)model takes into account Stokes radiance vector but derives its solution assuming azimuthal symmetric surface reflective matrix and atmospheric scattering phase matrix,such as the phase matrix derived from spherical particles or randomly oriented non-spherical particles.In this study,a new VDISORT is developed for general atmospheric scattering and boundary conditions.Stokes vector is decomposed into both sinusoidal and cosinusoidal harmonic modes,and the radiance at arbitrary viewing geometry is solved directly by adding two zero-weighted points in the Gaussian quadrature scheme.The complex eigenvalues in homogeneous solutions are also taken into full consideration.The accuracy of VDISORT model is comprehensively validated by four cases:Rayleigh scattering case,the spherical particle scattering case with the Legendre expansion coefficients of 0th-13th orders of the phase matrix(hereinafter L13),L13 with a polarized source,and the randomoriented oblate particle scattering case with the Legendre expansion coefficients of 0th-11th orders of the phase matrix(hereinafter L11).In all cases,the simulated radiances agree well with the benchmarks,with absolute biases less than 0.0065,0.0006,and 0.0008 for Rayleigh,unpolarized L13,and L11,respectively.Since a polarized bidirectional reflection distribution function(pBRDF)matrix is used as the lower boundary condition,VDISORT is now able to handle fully coupled atmospheric and surface polarimetric radiative transfer processes.

MAXIMAL SCHWARZSCHILD GEOMETRY DESCRIBED BY THE WEYL COORDINATES

Using the imaginary coordinate method given by Ref. [1] it has been proved that the maximal Schwarzschild geometry can be described by the Weyl coordinates. It is well known that the metric of the field of. a Schwarzschild particle m in the Schwarzschild coordinate system

Convergence of the Modified Discrete Ordinates Method for the Anisotropic Scattering Transport Equation

Criticality problem of nuclear tractors generMly refers to an eigenvalue problem for the transport equations. In this paper, we deal with the eigenvalue of the anisotropic scattering transport equation in slab geometry. We propose a new discrete method which was called modified discrete ordinates method. It is constructed by redeveloping and improving discrete ordinates method in the space of L1（X）. Different from traditional methods, norm convergence of operator approximation is proved theoretically. Furthermore, convergence of eigenvalue approximation and the corresponding error estimation are obtained by analytical tools.

RECENT DEVELOPMENT OF DISCRETE ORDINATE METHOD IN COMPUTATION OF RADIATIVE TRANSFER IN ANISOTROPICALLY SCATTERING ATMOSPHERE

Ⅰ. INTRODUCTIONSince the discrete ordinate method was introduced by Chandrasekhar in 1950, it has been used by many investigators to study radiative transfer problems in atmosphere, and ex tended the description of radiative transfer from homogeneous medium to

THE RATIONALITY OF THE DISCRETE ORDINATES METHOD FOR TIME DEPENDENT NEUTRON TRANSPORT EQUATION

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INTENSITY CALCULATION IN STRONGLY ANISOTROPICALLY SCATTERING ATMOSPHERE WITH DISCRETE ORDINATE METHOD

The problems in some previous discrete ordinate method computations of radiative transfer are discussed, and a new manipulation is presented, which overcomes the difficulties in intensity calculations with the discrete ordinate method, and can be used to obtain accurate intensities with less streams. Even in strongly anisotropically scattering atmospheres the intensities in all directions including forward and backward directions of the direct radiation can be obtained satisfactorily.

Two Uniform Tailored Finite Point Schemes for the Two Dimensional Discrete Ordinates Transport Equations with Boundary and Interface Layers

This paper presents two uniformly convergent numerical schemes for the two dimensional steady state discrete ordinates transport equation in the diffusive regime,which is valid up to the boundary and interface layers.A five-point nodecentered and a four-point cell-centered tailored finite point schemes(TFPS)are introduced.The schemes first approximate the scattering coefficients and sources by piecewise constant functions and then use special solutions to the constant coefficient equation as local basis functions to formulate a discrete linear system.Numerically,both methods can not only capture the diffusion limit,but also exhibit uniform convergence in the diffusive regime,even with boundary layers.Numerical results show that the five-point scheme has first-order accuracy and the four-point scheme has second-order accuracy,uniformly with respect to the mean free path.Therefore a relatively coarse grid can be used to capture the two dimensional boundary and interface layers.

Applying an Ordinal Priority Approach Based Neutrosophic Fuzzy Axiomatic Design Approach to Develop Sustainable Geothermal Energy Source

Geothermal energy is considered a renewable,environmentally friendly,especially carbon-free,sustainable energy source that can solve the problem of climate change.In general,countries with geothermal energy resources are the ones going through the ring of fire.Therefore,not every country is lucky enough to own this resource.As a country with 117 active volcanoes and within the world’s ring of fire,it is a country whose geothermal resources are estimated to be about 40%of the world’s geothermal energy potential.However,the percentage used compared to the geothermal potential is too small.Therefore,this is the main energy source that Indonesia is aiming to exploit and use.However,the deployment and development of this energy source are still facing many obstacles due to many aspects from budget sources due to high capital costs,factory construction location,quality of resources,and conflicts of the local community.In this context,determining the optimal locations for geothermal energy sites(GES)is one of the most important and necessary issues.To strengthen the selection methods,this study applies a two-layer fuzzy multi-criteria decision-making method.Through the layers,the Ordinal Priority Approach(OPA)is proposed to weight the sub-criteria,the main criterion,and the sustainability factors.In layer 2,the Neutrosophic Fuzzy Axiomatic Design(NFAD)is applied to rank and evaluate potential locations for geothermal plant construction.Choosing the right geothermal energy site can bring low-cost efficiency,no greenhouse gas emissions,and quickly become the main energy source providing electricity for Indonesia.The final ranking shows Papua,Kawah Cibuni,and Moluccas as the three most suitable cities to build geothermal energy systems.Kawah Cibuni was identified as the most potential GES in Indonesia,with a score of 0.46.Papua is the second most promising GES with a score of 0.45.Next is the Moluccas,with a score of 0.39.However,the three least potential sites among the 15 studied sites are Lumut Balai,Moluccas and Patuha,with scores of 0.08,0.11 and 0.17,respectively.The conclusion of this study also classifies positions into groups to aid in decision-making.

The Absence of “Perfect Induction”in the Science

The present paper is finalized to show that the Science, even if considered in its two different Phenomenological Approaches at present known, is unable to assert that: “Thinks are like that”. This is because both the two Scientific Approaches previously mentioned have not the property of “the perfect induction”. Consequently, although they can even reach an experimental confirmation of the theoretical results, and thus a “valid description” of the various phenomena of the surrounding world, such a description has not an “absolute value”. In fact, it always and only has an “operative validity”, that is, it exclusively and solely refers to an “experimental point of view”. This means that such an “operative validity” cannot represent the basis for a logical process characterized by a “perfect induction”. In addition, the Traditional Scientific Approach is also characterized by “Insoluble” Problems, “Intractable Problems”, Problems with “drifts”, which could generally be termed as “side effects”. On the other hand, the same com-possible Scientific Approach based on the Emerging Quality of Self-Organizing Systems, also presents its “Emerging Exits”. Consequently, none of the two mentioned scientific Approaches has the “gift” of “the perfect induction”. However, there are significant differences between the two. Differences that may “suggest” the most appropriate choice among them for an “operative point of view”. This conclusion will be com-proved by considering, with particular reference, both the “side effects”, which are related to the Traditional Approach and, on the other hand, the “Emerging Exits”, which specifically pertain to the new Scientific Approach based on the Emerging Quality of Self-Organizing Systems.

The Accelerated Expansion of the Universe in the Light of the Maximum Ordinality Principle

The main aim of the paper is to present (and at the same time offer) a differ-ent perspective for the analysis of the accelerated expansion of the Universe. A perspective that can surely be considered as being “in parallel” to the tradition-al ones, such as those based, for example, on the hypotheses of “Dark Matter” and “Dark Energy”, or better as a “com-possible” perspective, because it is not understood as being “exclusive”. In fact, it is an approach that, when con-firmed by experimental results, always keeps its validity from an “operative” point of view. This is because, in analogy to the traditional perspectives, on the basis of Popper’s Falsification Principle the corresponding “Generative” Logic on which it is based has not the property of the perfect induction. The basic difference then only consists in the fact that the Evolution of the Universe is now modeled by considering the Universe as a Self-Organizing System, which is thus analyzed in the light of the Maximum Ordinality Principle.

农民工城市融合路径及影响因素研究——基于三阶段Ordinal Logit模型的实证

本文依据浙江省农民工城市融合的调查数据,构建三阶段Ordinal Logit模型实证分析了农民工城市融合路径及影响因素。结果表明,农民工城市融合经历经济生存融合、社会交往融合和心理认同三阶段发展路径,经济生存融合由强到弱受职业资格、就业公平、婚姻状况、初始社会资本和居住条件的影响;社会交往融合由强到弱受居住格局、经济生存融合、经济生存状态的未来期许和上网时间的影响;心理认同由强到弱受社会交往融合、长期居留意愿和乡土记忆的影响。整合分析表明,经济生存融合极大制约了农民工城市融合的纵向提升,当前农民工城市融合仍停留在经济生存融合阶段。促进农民工城市融合的政策建议应着重考虑以上因素。

基于Ordinal Logistic模型的事故严重性影响因素分析——以翻车事故为例

为准确分析影响交通事故严重性的各项因素,引入Ordinal Logistic模型研究驾驶员、车辆、环境因素对事故严重程度的影响,利用统计学方法对模型进行显著性检验。并使用该模型对北卡罗来纳州2010—2014年385个翻车事故样本进行严重性影响因素分析,所得回归模型符合平行线检验(=0.115 1)和似然比检验(≤0.000 1)。通过模型分析得出变量"安全带"(≤0.000 1)、"路面状况"(=0.013 6)、"道路线形"(=0.005 7)对翻车事故的严重性具有显著影响,研究结果表明:Ordinal Logistic模型适合于分析与揭示影响交通事故严重性的各个因素。

Characteristics,classification and ordination of riparian plant communities in the Three-Gorges areas

Sixteen different vegetation types of grassland and shrubland were selected to study the component and diversity of plant species of riparian plant communities along main channel in the Three-Gorges areas. Species richness (s), Simpson index (D), and Shannon-Weiner index (H) were used to study the biodiversity and the hierarchical classification was carried out by the methods of TWINSPAN and DCA ordination. The results showed that the components of flora were complex and dominated by the temperate type in the riparian plant communities. Species diversity was not different between the communities, but Shannon-Weiner indexes of different layers in some grassland were significantly different. TWINSPAN and DCA indicated that riparian plant communities distributed along the gradient of moisture.

基于有序Logit与Probit模型的交通事故严重性影响因素分析

为准确分析影响交通事故严重性的各项因素,引入有序选择模型中的Ordinal Logit模型和Ordinal Probit模型,研究驾驶员、车辆、环境、管理因素与事故严重程度之间的耦合关系,利用计量经济学理论和统计学方法对模型进行显著性检验。并选择美国北卡罗来纳州2010年至2014年385个翻车事故样本进行严重性影响因素分析,所得回归模型参数估计均符合Wald检验（p≤0.0001）和似然比检验（p≤0.0001）,模型的拟合度也都符合Pearson检验（p=0.7976）、偏差检验（p=0.6006）和信息准则检验,模型预测精度指标值均大于0.7。所得两个模型中变量＂安全带＂（p≤0.001）、＂路面状况＂（p=0.0071）、＂道路线形＂（p=0.0077）、＂路面类型＂（p=0.0251）都对翻车事故的严重性具有显著影响,表明有序Logit模型和有序Probit模型均适用于分析和揭示影响交通事故严重性的各个因素。

农村学校撤并对学生上学距离的影响——基于GIS和Ordinal Logit模型的分析

农村义务教育学校布局调整是以撤并小规模学校为主要手段,旨在促进教育资源均衡配置的一项重大教育政策。通过广东省某山区县2003—2009年的学校布局规划数据,从物理距离、时间距离和文化距离的分类视角,运用GIS技术和Ordinal Logit模型分析农村学校撤并对学生上学距离产生的直接影响。研究结果表明:撤并农村学校导致学生上学的物理距离和时间距离增加,偏远学生上学难问题凸显;对学生的文化距离同样产生显著的负面影响。在未来学校布局调整的进程中,县域教育决策者应将关注点从一味追求规模效益转移到教育公平和教育质量上来。要保证农村学生就近入学,设定上学距离的限制;促进学校间教育资源的均衡配置,保证所有学生享受同等质量的教育资源;采用科学的规划程序完善布局调整政策的实施。

粮农综合补贴对农户种粮积极性的影响分析——以内蒙古太仆寺旗种植业农户为例

为了验证粮农综合补贴政策能否影响农户生产积极性,进而影响粮食生产。本文对内蒙古太仆寺旗从事种植业生产的农户进行了问卷调查,选取在维持目前粮农综合补贴标准和发放方式不变的情况下,农户对3年后种植粮食作物表达出的意愿和态度这一微观视角进行研究。Ordinal回归模型拟合结果及相关统计分析表明,由于补贴占收入比重较小,以种粮为主农户的收入远低于外出打工和兼业农户的收入水平,因此,补贴对未来农户种粮积极性的增加没有起到激励作用,反而是目前获得补贴较高的被调研农户,未来不愿意种粮的倾向性更高,长期发展我国种粮的有效劳动力可能更加缺乏。为此,本文提出在稳定现有补贴政策的基础上,鼓励规模化种粮,提高种粮农户的收益,以及在WTO规则允许范围内实施与粮食播种面积挂钩的补贴并提高补贴标准,进而提高农户生产积极性的政策建议。

基层农技人员对农业科技入户工程的价值认同及其影响因素分析

基层农技人员对农业科技入户工程的价值认同是影响农业技术推广效率的关键因素。调查湖北省378位基层农技人员对农业科技入户工程的价值认同情况,并用Ordinal模型对影响其价值认同的因素进行实证分析。研究结果表明:第一,基层农技人员对农业科技入户工程的价值认同程度不高;第二,文化程度、月收入、地方政府对农业推广的重视程度、对科技政策的了解程度等变量是影响基层农技人员对农业科技入户认同程度的关键因素。

个体特征、补偿机制与农民对新农合的满意度

文章基于2012年对新疆726位农民的调查数据,利用Ordinal Logistic回归模型,实证分析个体特征、补偿机制与农民对新农合满意度的影响。结果表明:农民对新农合的满意度比较高;补偿机制总体合理性及其五个方面的合理性,显著影响农民对新农合的满意度;年龄越大、政治面貌为党(团)员、少数民族的农民,对新农合的满意度更高。农民对新农合的满意度主要取决于农民的受益水平,同时也受到新农合缴费标准合理性、服务和监督管理水平的影响。提高农民对新农合的满意度,首先要适当提高新农合补偿比例,适度扩大新农合补偿范围,合理确定农民缴费标准;同时,要简化新农合补偿手续,提高补偿的便利性,加强监督管理,促进补偿的公平性。