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The purpose of this paper is to investigate the relationship between a student’s study time and the learning outcome from a perspective that will correspond to Bloom’s (1956) taxonomy and how teaching can be developed using variation theory.

The author designed a learning study using an experiment with three different classes of students. The experimental research question was “Does a student’s study time (massed or distributed spacing) have an impact on the learning process?”

Results indicated that students in the “strictly supervised study time” grouping improved on their learning outcomes more than those in the “not strictly supervised study time” equivalent and those in the control group. It is important for students to manage their own learning activities and follow a regular study routine to improve their learning outcomes.

This study used undergraduate students at a university in Ghana, and its findings may not necessarily be applicable to other populations. One other limitation was that the author did not control for the lecturer’s expectations and how these may have influenced students’ learning outcomes. Another potential limitation was that total quality management was the only subject area used for this study.

The objective of the study was to use the motivated strategies for learning questionnaire (MSLQ) approach by Pintrich et al. (1991) to determine the relationship between a student’s study time and the impact on their learning outcomes. The results imply that students must take more active roles in their learning by having regular study time.

Currently, to the best of the author’s knowledge, there are not many experiment-based research studies on a student’s study time using the MSLQ approach by Pintrich et al. (1991). This study contributes to the existing literature by examining how a student’s study time (massed or distributed spacing) has an impact on the learning outcome as a lesson and learning study.

This paper aims to clarify the relationship between the student’s study time and the learning process in the higher education system by adapting the total quality management (TQM) principles-process approach. Contrary to Deming’s (1982) constancy of purpose to improve the learning process, some students in higher education postpone their studies till the last few weeks of an examination.

The paper opted for an experimental study with three different classes of business school students. The experimental research question was “Do student’s study time (massed or distributed spacing) has an impact on the learning process?”

Results indicated that students in the “Strictly supervised study time” group improved on their learning process more than the “Not Strictly Supervised study time” and the control group. It is important for students to manage their own learning activities and follow a regular study time and constantly improve their learning process as proposed by Deming (1982).

This study used restricted to undergraduate business school students in a university in Ghana, and may not necessarily be applicable universally. One other limitation was that the authors did not control for lecturer’s expectancies and how these may have influenced the students’ learning process. Another potential limitation was that TQM was the only subject area used for this study.

This objective of the study is to use the TQM principles of process approach, the Learning Theory and the Learning Strategies from the Motivated Strategies for Learning Questionnaire (MSLQ) – Pintrich et al. (1991) – to support theoretical and practical implications of the relationship between the student’s study time and the learning process. The results imply that students must take a more active role in their learning by having a regular study time.

Currently, to the best of the authors’ knowledge, there are not many experiment-based studies on a student’s study time using the MSLQ-Pintrich et al. (1991) approach. This study contributes to the literature by examining how a student’s study time (massed or distributed spacing) has an impact on the learning process.

Anecdotal evidence indicates that one of the more difficult issues faced by accounting students is the understanding and preparation of the statement of cash flows (SCF). This study investigates the impact of different instruction methods for covering the statement on student learning outcomes. Currently, two prominent intermediate-level financial accounting texts cover the SCF primarily in one end-of-text chapter, a massed presentation. The current study argues that the SCF is a topic that is cross-sectional in nature, and is applicable to the textbook material on the accounting transactions that are spread throughout the texts. In accordance with the spacing effect (Dempster, 1988), instruction of SCF material across the major recognition and measurement topic chapters, a spaced presentation format, potentially yields enhanced learning outcomes in comparison to the massed presentation.

Across three semesters of an intermediate-level financial accounting course, the SCF delivery format and coverage were varied in a 1 × 3 between-subjects experiment. The subjects completed an indirect-method SCF preparation task, which I analyzed across the three conditions.

Students learning the SCF presentation of intermediate-level transactions in a spaced presentation earned higher scores on the task compared to those learning the material in a massed format. Furthermore, the students exposed to the massed presentation performed no better than those not instructed on the material.

I base my findings on the results of one assessment of the SCF in one course. Future research should consider various tasks related to the SCF at different course levels and across a variety of instructional techniques.

The results imply that changes to the delivery of SCF material could potentially produce benefits to student learning.

Multi-well hydrofracturing is an important technology to create new fractures and expand existing fractures to increase reservoir permeability. The propagation morphology of the fracture network is affected by the disturbance between the fractures initiation sequences and spacings between adjacent wells. However, it remains unclear how well spacing and initiation sequences lead to fracture propagation, deflection and connection.

In this study, the thermal-hydro-mechanical coupling effect in the hydrofracturing process was considered, to establish a finite element-discrete element model of multistage hydrofracturing in a horizontal well. Using typical cases, the unstable propagation of hydraulic fractures in multiple horizontal wells was investigated under varying well spacing and initiation sequences. Combined with the shear stress shadow caused by in situ stress disturbed by fracture tip propagation, the quantitative indexes of fracture propagation such as length, volume, displacement vector, deflection and unstable propagation behavior of the hydrofracturing fracture network were analyzed.

The results show that the shear stress disturbance caused by multiple hydraulic fractures is a significant factor in multi-well hydrofracturing. Reducing the spacing between multiple wells increases the stress shadow area and aggravates the mutual disturbance and deflection between the fractures. The quantitative analysis results show that a decrease of well spacing reduces the total length of hydraulic fractures but increases the total volume of the fracture; compared with sequential and simultaneous fracturing, alternate fracturing can effectively reduce stress shadow area, alleviate fracture disturbance and generate larger fracture propagation length and volume.

The numerical models and results of the unstable propagation and stress evolution of the hydraulic fracture network under thermal-hydro-mechanical coupling obtained in this study can provide useful guidance for the evaluation and design of rock mass fracture networks in deep unconventional oil and gas reservoirs.

A model for calculating the global overpressure time history of a single cloud detonation from overpressure time history of discrete positions in the range of single cloud detonation is to be proposed and verified. The overpressure distribution produced by multiple cloud detonation and the influence of cloud spacing and fuel mass of every cloud on the overpressure distribution are to be studied.

A calculation method is used to obtain the global overpressure field distribution after single cloud detonation from the overpressure time history of discrete distance to detonation center after single cloud detonation. On this basis, the overpressure distribution produced by multi-cloud under different cloud spacing and different fuel mass conditions is obtained.

The results show that for 150 kg fuel, when the spacing of three clouds is 40 m, 50 m, respectively, the overpressure range of larger than 0.1 MPa is 5496.48 mˆ2 and 6235.2 mˆ2, which is 2.89 times and 3.28 times of that of single cloud detonation. The superposition effect can be ignored when the spacing between the three clouds is greater than 60 m. In the case of fixed cloud spacing, once the overpressure forms continuous effective superposition, the marginal utility of fuel decreases.

A model for calculating the global overpressure time history of a single cloud detonation from overpressure time history of discrete positions in the range of single cloud detonation is proposed and verified. Based on this method, the global overpressure field of single cloud detonation is reconstructed, and the superimposed overpressure distribution characteristics of three cloud detonation are calculated and analyzed.

In this work, an SFEM is proposed for solving acoustic problems by redistributing the entries in the mass matrix to “tune” the balance between “stiffness” and “mass” of discrete equation systems, aiming to minimize the dispersion error. The paper aims to discuss this issue.

This is done by simply shifting the four integration points’ locations when computing the entries of the mass matrix in the scheme of SFEM, while ensuring the mass conservation. The proposed method is devised for bilinear quadratic elements.

The balance between “stiffness” and “mass” of discrete equation systems is critically important in simulating wave propagation problems such as acoustics. A formula is also derived for possibly the best mass redistribution in terms of minimizing dispersion error reduction. Both theoretical and numerical examples demonstrate that the present method possesses distinct advantages compared with the conventional SFEM using the same quadrilateral mesh.

After introducing the mass-redistribution technique, the magnitude of the leading relative dispersion error (the quadratic term) of MR-SFEM is bounded by (5/8), which is much smaller than that of original SFEM models with traditional mass matrix (13/4) and consistence mass matrix (2). Owing to properly turning the balancing between stiffness and mass, the MR-SFEM achieves higher accuracy and much better natural eigenfrequencies prediction than the original SFEM does.

The purpose of this study is to investigate the unstable propagation of parallel hydraulic fractures induced by interferences of adjacent perforation clusters and thermal diffusion. Fracture propagation in the process of multistage fracturing of a rock mass is deflected owing to various factors. Hydrofracturing of rock masses in deep tight reservoirs involves thermal diffusion, fluid flow and deformation of rock between the rock matrix and fluid in pores and fractures.

To study the unstable propagation behaviours of three-dimensional (3D) parallel hydraulic fractures induced by the interferences of adjacent perforation clusters and thermal diffusion, a 3D engineering-scale numerical model is established under different fracturing scenarios (sequential, simultaneous and alternate fracturing) and different perforation cluster spacings while considering the thermal-hydro-mechanical coupling effect. Stress disturbance region caused by fracture propagation in a deep tight rock mass is superimposed and overlaid with multiple fractures, resulting in a stress shadow effect and fracture deflection.

The results show that the size of the stress shadow areas and the interaction between fractures increase with decreasing multiple perforation cluster spacing in horizontal wells. Alternate fracturing can produce more fracture areas and improve the fracturing effect compared with those of sequential and simultaneous fracturing. The larger the temperature gradient between the fracturing fluid and rock matrix, the stronger the thermal diffusion effect, and the effect of thermal diffusion on the fracture propagation is significant.

This study focuses on the behaviours of the unstable dynamic propagation of 3D parallel hydraulic fractures induced by the interferences of adjacent perforation clusters and thermal diffusion. Further, the temperature field affects the fracture deflection requires could be investigated from the mechanisms; this paper is to study the unstable propagation of fractures in single horizontal well, which can provide a basis for fracture propagation and stress field disturbance in multiple horizontal wells.

For gravity dams built on foundations with directional joint sets, the seepage in the foundation possesses anisotropic characteristics and may have adverse effects on the foundation stability. A methodology for system reliability analysis of gravity dam foundations considering anisotropic seepage and multiple sliding surfaces is proposed in this paper.

Anisotropic seepages in dam foundations are simulated using finite element method (FEM) with the equivalent continuum model (ECM), and their effect on dam foundation stability is involved by uplift pressures acting on the potential sliding surfaces. The system failure probability of the dam foundation is efficiently estimated using Monte Carlo method (MCM) combined with response surface method (RSM).

The case study shows that it is necessary to consider the possibly adverse effect of anisotropic seepage on foundation stability of gravity dams and the deterministic analysis of the foundation stability may be misleading. The system reliability analysis of the dam foundation is justified, as the uncertainties in shear strength parameters of the foundation rocks and joint sets as well as aperture, connectivity and spacing of the joint sets are quantified and the system effect of the multiple potential sliding surfaces on the foundation reliability is reasonably considered.

(1) A methodology is proposed for efficient system reliability analysis of foundation stability of gravity dams considering anisotropic seepage and multiple sliding surfaces (2) The influence of anisotropic seepage on the stability of gravity dam foundation  is revealed (3) The influence of estimation errors of RSMs on the system reliability assessment of dam foundation is investigated.

The purpose of this paper is to describe a multi‐robot solution to the problem of chemical source localization, in which a team of inexpensive, simple vehicles with short‐range, low‐power sensing, communication, and processing capabilities trace a chemical plume to its source emitter

The source localization problem is analyzed using computational fluid dynamics simulations of airborne chemical plumes. The analysis is divided into two parts consisting of two large experiments each: the first part focuses on the issues of collaborative control, and the second part demonstrates how task performance is affected by the number of collaborating robots. Each experiment tests a key aspect of the problem, e.g. effects of obstacles, and defines performance metrics that help capture important characteristics of each solution.

The new empirical simulations confirmed previous theoretical predictions: a physics‐based approach is more effective than the biologically inspired methods in meeting the objectives of the plume‐tracing mission. This gain in performance is consistent across a variety of plume and environmental conditions. This work shows that high success rate can be achieved by robots using strictly local information and a fully decentralized, fault‐tolerant, and reactive control algorithm.

This is the first paper to compare a physics‐based approach against the leading alternatives for chemical plume tracing under a wide variety of fluid conditions and performance metrics. This is also the first presentation of the algorithms showing the specific mechanisms employed to achieve superior performance, including the underlying fluid and other physics principles and their numerical implementation, and the mechanisms that allow the practitioner to duplicate the outstanding performance of this approach under conditions of many robots navigating through obstacle‐dense environments.

Describes the thermo‐mechanical consolidation coupling analysis and its discretization method for the simulations of nuclear waste storage on jointed rock mass using the finite element method. An anisotropic stress‐strain and permeable constitutive laws are employed for combining arbitrary oriented joint sets using compliance matrices. Evaluates the influence of non‐linear permeability of joint by cubic‐law assuming parallel plate flow caused by excavation and the local change of permeability around the excavated cavern in different joint angles. The results of the two‐dimensional rock mass models with combining arbitrary oriented joint sets show that the fluid flow direction followed along the direction of the joint sets, and this seemed to be clearly explained from the influence of joint orientations.