A triangulation approach for design research

Triangulation has been adopted in social science in the study of the same phenomenon through applying and combining several data sources, research methods, investigators, and theoretical schemes. From a post-positivism view point, this paper presents a triangulation approach in design research from two perspectives, data sources and research methods. Data triangulation was achieved through collecting data from multiple sources including company design documents, student design projects, and company design projects. Different research methods, e.g. interview, content analysis, protocol analysis, and questionnaire, were used to conduct data collection and analysis into a particular aspect of design, the nature of coupling design artefact and process knowledge. It was found that triangulation can provide an effective means for design research

3D DEM Simulation of Crushable Granular Soils under Plane Strain Compression Condition

AbstractParticle crushing plays an important role on the mechanical behavior of crushable granular soils. In this paper, the macro- and micro-mechanical behaviors of dense granular soils composed of crushable agglomerates in plane strain compression test are investigated using the Discrete Element Method (DEM). A detailed study on the effects of particle crushing on the soil behavior is facilitated by a comparison between the simulation results of crushable and uncrushable specimens. The DEM results show a strong dependency of particle crushing on the confining stress level. It is found that under low confining stresses, particle crushing is insignificant and does not affect the shear band formation, which is the primary failure mode in an uncrushable specimen. However, under high confining stresses, significant particle crushing occurs and leads to considerable volumetric compression and reduction of the peak shear stress ratio. More importantly, particle crushing interferes with the formation of shear band and results in massive contractive zones in the specimen, which essentially controls the shear strength behavior

A tunable radiation source by coupling laser-plasma-generated electrons to a periodic structure

Near-infrared radiation around 1000 nm generated from the interaction of a high-density MeV electron beam, obtained by impinging an intense ultrashort laser pulse on a solid target, with a metal grating is observed experimentally. Theoretical modeling and particle-in-cell simulation suggest that the radiation is caused by the Smith-Purcell mechanism. The results here indicate that tunable terahertz radiation with tens GV=m field strength can be achieved by using appropriate grating parameter

3D DEM Simulation of Crushable Granular Soils under Plane Strain Compression Condition

AbstractParticle crushing plays an important role on the mechanical behavior of crushable granular soils. In this paper, the macro- and micro-mechanical behaviors of dense granular soils composed of crushable agglomerates in plane strain compression test are investigated using the Discrete Element Method (DEM). A detailed study on the effects of particle crushing on the soil behavior is facilitated by a comparison between the simulation results of crushable and uncrushable specimens. The DEM results show a strong dependency of particle crushing on the confining stress level. It is found that under low confining stresses, particle crushing is insignificant and does not affect the shear band formation, which is the primary failure mode in an uncrushable specimen. However, under high confining stresses, significant particle crushing occurs and leads to considerable volumetric compression and reduction of the peak shear stress ratio. More importantly, particle crushing interferes with the formation of shear band and results in massive contractive zones in the specimen, which essentially controls the shear strength behavior

Social work education as a catalyst for social change and social development: case study of a Master of Social Work Program in China

In response to the urgent need for professionally trained social workers to help in alleviating emerging social problems in China after the introduction of the market economy, the Hong Kong Polytechnic University and the Peking University launched a Master of Social Work (China) Program for social work educators in 2000, with the aim of developing a critical mass of social work educators to take up the future leadership in developing social work and social work education in China. To date, seven cohorts of over 230 students consisting of social work educators, NGO and government officials have been admitted to the program, and graduates of the program are playing a pivotal role in spearheading the development of social work education and fostering social development through the process. In this paper, the authors will present the vision and mission of the Master of Social Work (MSW) Program, the teaching and learning strategies adopted, and the ways in which the program has facilitated social change and social development through its educational process

In-Plane Magnetic Anisotropy In RF Sputtered Fe-N Thin Films

We have fabricated Fe(N) thin films with varied N2 partial pressure and studied the microstructure, morphology, magnetic properties and resistivity by using X-ray diffraction, atomic force microscopy, transmission electron microscopy, vibrating-sample magnetometer and angle-resolved M-H hysteresis Loop tracer and standard four-point probe method. In the presence of low N2 partial pressure, Fe(N) films showed a basic bcc a-Fe structure with a preferred (110) texture. A variation of in-plane magnetic anisotropy of the Fe(N) films was observed with the changing of N component. The evolution of in-plane anisotropy in the films was attributed to the directional order mechanism. Nitrogen atoms play an important role in refining the a-Fe grains and inducing uniaxial anisotropy.Comment: 11 pages, 6 figure

Lateral Size and Thickness Dependence in Ferroelectric Nanostructures Formed by Localized Domain Switching

Ferroelectric nanostructures can be formed by local switching of domains using techniques such as piezo-force microscopy (PFM). Understanding lateral size effects is important to determine the minimum feature size for writing ferroelectric nanostructures. To understand these lateral size effects, we use the time-dependent-Ginzburg-Landau equations to simulate localized switching of domains for a PFM type and parallel-plate capacitor configurations. Our investigations indicate that fringing electric fields lead to switching via 90 deg domain wedge nucleation for thicker films while at smaller thicknesses, the polarization switches directly by 180 deg rotations. The voltage required to switch the domain increases by decreasing the lateral size and at very small lateral sizes the coercive voltage becomes so large that it becomes virtually impossible to switch the domain. In all cases, the width of the switched region extends beyond the electrodes, due to fringing.Comment: 21 pages, 11 figure

Effective Dynamic Range in Measurements with Flash Analog-to-Digital Convertor

Flash Analog to Digital Convertor (FADC) is frequently used in nuclear and particle physics experiments, often as the major component in big multi-channel systems. The large data volume makes the optimization of operating parameters necessary. This article reports a study of a method to extend the dynamic range of an 8-bit FADC from the nominal $\rm{2^8}$ value. By comparing the integrated pulse area with that of a reference profile, good energy reconstruction and event identification can be achieved on saturated events from CsI(Tl) crystal scintillators. The effective dynamic range can be extended by at least 4 more bits. The algorithm is generic and is expected to be applicable to other detector systems with FADC readout.Comment: 19 pages, 1 table, 10 figure

Shear viscosity of hot scalar field theory in the real-time formalism

Within the closed time path formalism a general nonperturbative expression is derived which resums through the Bethe-Salpter equation all leading order contributions to the shear viscosity in hot scalar field theory. Using a previously derived generalized fluctuation-dissipation theorem for nonlinear response functions in the real-time formalism, it is shown that the Bethe-Salpeter equation decouples in the so-called (r,a) basis. The general result is applied to scalar field theory with pure lambda*phi**4 and mixed g*phi**3+lambda*phi**4 interactions. In both cases our calculation confirms the leading order expression for the shear viscosity previously obtained in the imaginary time formalism.Comment: Expanded introduction and conclusions. Several references and a footnote added. Fig.5 and its discussion in the text modified to avoid double counting. Signs in Eqs. (45) and (53) correcte

Thermodynamic and Tunneling Density of States of the Integer Quantum Hall Critical State

We examine the long wave length limit of the self-consistent Hartree-Fock approximation irreducible static density-density response function by evaluating the charge induced by an external charge. Our results are consistent with the compressibility sum rule and inconsistent with earlier work that did not account for consistency between the exchange-local-field and the disorder potential. We conclude that the thermodynamic density of states is finite, in spite of the vanishing tunneling density of states at the critical energy of the integer quantum Hall transition.Comment: 5 pages, 4 figures, minor revisions, published versio