Search results

Experimental economics has been treated with skepticism by some Austrian economists. We argue that experimental methods are consistent with strong versions of praxeology, and are therefore not methodologically problematic for Austrians. We further argue that experimental research methods have illustrated many uniquely Austrian themes and provide a fruitful method for future Austrian-inspired research.

In the fast paced PCB industry of today windows of opportunity are short. One needs to be able to find quickly the key variables to a new process or an existing process so that the capability requirement can be met. Guesswork and traditional experimental design approaches will not work. Control charts by themselves will not work. Very large experimental studies will not work. What will work are simple, well defined, statistically designed experiments. This paper is an example of how simple, statistically based experiments were used to reduce haloing on Teflon® circuit boards. The drilling and plating processes using different laminate materials were investigated using Box‐Wilson and Plackett‐Burman experimental designs. Different data analysis techniques such as confidence intervals, scree plots, analysis of variance tables and analysis of means charts were used to determine the true significant (key) variables and the insignificant (non key) variables. An effective experimental study must have a capable measurement system. A method of determining the measurement system capability and improving it for haloing using isoplots is presented. In the end, two economically feasible paths to reduce the haloing problem were found.

The present work is an experimental and numerical study of a sloshing problem including baffle effects. The purpose of this paper is to assess the numerical behavior of a Lagrangian technique to track free surface flows by comparison with experiments, to report experimental data for sloshing at different conditions and to evaluate the effectiveness of baffles in limiting the wave height and the wave propagation.

Finite element simulations performed with a fixed mesh technique able to describe the free surface evolution are contrasted with experimental data. The experiments consist of an acrylic tank of rectangular section designed to attach baffles of different sizes at different distance from the bottom. The tank is filled with water and mounted on a shake table able to move under controlled horizontal motion. The free surface evolution is measured with ultrasonic sensors. The numerical results computed for different sloshing conditions are compared with the experimental data.

The reported numerical results are in general in good agreement with the experiments. In particular, wave heights and frequencies response satisfactorily compared with the experimental data for the several cases analyzed during steady state forced sloshing and free sloshing. The effectiveness of the baffles increases near resonance conditions. From the set of experiments studied, the major reduction of the wave height was obtained when larger baffles were positioned closer to the water level at rest.

Model validation: evaluation of the effectiveness of non-massive immersed baffles during sloshing.

The value of the present work encompass the numerical and experimental study of the effect of immersed baffles during sloshing under different imposed conditions and the comparison of numerical results with the experimental data. Also, the results shown in the present work are a contribution to the understanding of the role in the analysis of the proposed problem of some specific aspects of the geometry and the imposed motion.

The purpose of this paper is to argue that the time is ripe to establish a powerful tradition in Experimental International Business (IB). Probably due to what the Arjen van Witteloostuijn refers to as the external validity myth, experimental laboratory designs are underutilized in IB, which implies that the internal validity miracle of randomized experimentation goes largely unnoticed in this domain of the broader management discipline.

In the following pages, the author explains why the author believes this implies a missed opportunity, providing arguments and examples along the way.

Although an Experimental Management tradition has never really gained momentum, to the author, the lab experimental design has a very bright future in IB (and management at large). To facilitate the development of an Experimental IB tradition, initiating web-based tools would be highly instrumental. This will not only boost further progress in IB research, but will also increase the effectiveness and playfulness of IB teaching.

Given the high potential of an Experimental IB, the Cross-Cultural and Strategic Management journal will offer a platform for such exciting and intriguing laboratory work, cumulatively contributing to the establishment of an Experimental IB tradition.

The purpose of this paper is to prevent their recession caused through chemical reaction with high-temperature water vapor, SiC-fiber/SiC-matrix ceramic-matrix composite (CMC) components used in gas-turbine engines are commonly protected with so-called environmental barrier coatings (EBCs). EBCs typically consist of three layers: a top thermal and mechanical protection coat; an intermediate layer which provides environmental protection; and a bond coat which assures good EBC/CMC adhesion. The materials used in different layers and their thicknesses are selected in such a way that the coating performance is optimized for the gas-turbine component in question.

Gas-turbine engines, while in service, often tend to ingest various foreign objects of different sizes. Such objects, entrained within the gas flow, can be accelerated to velocities as high as 600 m/s and, on impact, cause substantial damage to the EBC and SiC/SiC CMC substrate, compromising the component integrity and service life. The problem of foreign object damage (FOD) is addressed in the present work computationally using a series of transient non-linear dynamics finite-element analyses. Before such analyses could be conducted, a major effort had to be invested toward developing, parameterizing and validating the constitutive models for all attendant materials.

The computed FOD results are compared with their experimental counterparts in order to validate the numerical methodology employed.

To the authors’ knowledge, the present work is the first reported study dealing with the computational analysis of the FOD sustained by CMCs protected with EBCs.

This study aims to examine the extent to which “What Works” reviews in youth justice enable understanding of the features of effectiveness (what works, for whom, in what circumstances and why?) specified in the Effects–Mechanisms–Moderators–Implementation–Economic cost (EMMIE) framework.

The EMMIE framework examined findings within a sample of “What Works” style reviews of preventative youth justice intervention effectiveness.

“What Works” style reviews of evaluations of preventative youth justice interventions often omit the requisite details required to examine all of the necessary elements of effectiveness contained within the EMMIE framework. While effectiveness measures were typically provided, the dominant evaluation evidence-base struggles to consider moderators of effect, mechanisms of change, implementation differences and cost-effectiveness. Therefore, “What Works” samples cannot facilitate sufficient understanding of “what works for whom, in what circumstances and why?”. The authors argue that Realist Synthesis can fill this gap and shed light on the contexts that shape the mechanisms through which youth justice interventions work.

The authors extended the approach adopted by an earlier review of effectiveness reviews (Tompson et al., 2020), considering more recent reviews of the effectiveness of preventative interventions using the EMMIE framework. Unlike previous reviews, the authors prioritised the utility of the EMMIE framework for assessing the factors affecting the effectiveness of preventative interventions in youth justice.

Work environment change from the traditional cell- and open-space offices to activity-based work (ABW) generates many concerns among workforce and management. The purpose of this study is to observe impacts of ABW change on several knowledge work performance drivers and outputs.

A quasi-experimental design was applied to distinguish the impact of ABW on several dimensions of knowledge work performance in three governmental organizations. The empirical measures that were observed in the study were: perceptions of physical environment, virtual environment and social environment, individual ways of working, well-being at work and self-assessed productivity.

Well-being at work or productivity will not collapse because of ABW change. Most of the facets of self-assessed productivity and all of the well-being facets did not change because of the adoption of ABW. ABW change had a positive impact on group work effectiveness but negative effect on perceptions of the facilities as conducive for efficient working. ABW change had an enhancing effect on the routine of protecting one’s concentration from software-induced interruptions and decreasing effect on using mobile technologies to work during idle times and using technology to avoid unnecessary traveling. ABW change made telework more acceptable.

To the best of the authors’ knowledge, this study was one the first studies following real-world change to ABW with quasi-experimental design. The difference-in-differences approach made it possible to isolate the causal impact of ABW change on the knowledge work performance drivers and outputs from other simultaneous changes taking place in the studied workplaces.

IT is the painful experience of all who engage in experimental work of a type to which they are not accustomed, that they may easily spend more time in rectifying faults in their equipment or technique than in producing useful data. Information on these points has, therefore, considerable value to the investigator, but the supply of such information has hitherto been scanty. One reason for this, as regards research on internal combustion engines, is that, except for Government Establishments, which are naturally uncommunicative, and Universities, whose work is mainly educational rather than experimental, there are few organisations which carry out research on a scale wide enough to amass a large body of experience. One such firm is Messrs. Ricardo & Co., Ltd., who have been engaged on work of this kind for the last fifteen years. The description in these pages of their Shoreham Laboratory, and of their experimental methods, should, therefore, be of use to many. The writers (who are on the staff or Messrs. Ricardo & Co.) realise that the requirements of experimental work vary enormously, and that methods which suit their needs may not suit the needs of others. They have endeavoured, therefore, to explain not only how things are done, but why they are done in that particular way, and thus to give their readers an insight into the factors governing the choice of method, which they can apply to their own particular problems.

The problem of image retrieval and image description exists in various fields. In this paper, a model of content-based image retrieval and image content extraction based on the KD-Tree structure was proposed.

A Random Forest structure was built to classify the objects on each image on the basis of the balanced multibranch KD-Tree structure. From that purpose, a KD-Tree structure was generated by the Random Forest to retrieve a set of similar images for an input image. A KD-Tree structure is applied to determine a relationship word at leaves to extract the relationship between objects on an input image. An input image content is described based on class names and relationships between objects.

A model of image retrieval and image content extraction was proposed based on the proposed theoretical basis; simultaneously, the experiment was built on multi-object image datasets including Microsoft COCO and Flickr with an average image retrieval precision of 0.9028 and 0.9163, respectively. The experimental results were compared with those of other works on the same image dataset to demonstrate the effectiveness of the proposed method.

A balanced multibranch KD-Tree structure was built to apply to relationship classification on the basis of the original KD-Tree structure. Then, KD-Tree Random Forest was built to improve the classifier performance and retrieve a set of similar images for an input image. Concurrently, the image content was described in the process of combining class names and relationships between objects.

Impinging jets have been widely studied, and the addition of swirl has been found to be beneficial to heat transfer. As there is no literature on Reynolds-averaged Navier Stokes equations (RANS) nor experimental data of swirling jet flows generated by a rotating pipe, the purpose of this study is to fill such gap by providing results on the performance of this type of design.

As the flow has a different behaviour at different parts of the design, the same turbulent model cannot be used for the full domain. To overcome this complexity, the simulation is split into two coupled stages. This is an alternative to use the costly Reynold stress model (RSM) for the rotating pipe simulation and the SST k-ω model for the impingement.

The addition of swirl by means of a rotating pipe with a swirl intensity ranging from 0 up to 0.5 affects the velocity profiles, but has no remarkable effect on the spreading angle. The heat transfer is increased with respect to a non-swirling flow only at short nozzle-to-plate distances H/D < 6, where H is the distance and D is the diameter of the pipe. For the impinging zone, the highest average heat transfer is achieved at H/D = 5 with swirl intensity S = 0.5. This is the highest swirl studied in this work.

High-fidelity simulations or experimental analysis may provide reliable data for higher swirl intensities, which are not covered in this work.

This two-step approach and the data provided is of interest to other related investigations (e.g. using arrays of jets or other surfaces than flat plates).

This paper is the first of its kind RANS simulation of the heat transfer from a flat plate to a swirling impinging jet flow issuing from a rotating pipe. An extensive study of these computational fluid dynamics (CFD) simulations has been carried out with the emphasis of splitting the large domain into two parts to facilitate the use of different turbulent models and periodic boundary conditions for the flow confined in the pipe.