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Time and frequency domain complementary numerical models of microwave non‐linear circuits using two‐terminal active semiconductor devices are presented. Their main feature is the use of numerical one‐dimensional macroscopic physical models as semiconductor device models. Their respective capability is illustrated by some results of a study devoted to the optimization of millimeter‐wave avalanche diode frequency multipliers.

A non‐equilibrium multi‐valley transport model for carriers in compound semiconductor devices has been developed. This macroscopic transport model provides an efficient scheme for device modeling, and can overcome the difficulty in evaluating the relaxation times in multi‐valley conservation equations without a priori assumption of the displaced‐Maxwellian distribution. This model has been successfully applied to electron transport in GaAs subjected to rapidly time‐varying fields. The results have suggested that the macroscopic effective mass of electrons might be strongly dependent on average velocity.

The purpose of this paper is to analyze the performance of a data center and thermal management by using phase change material (PCM). Numerical studies were conducted for two dimensional model of data center and installation of PCM at different locations.

Finite volume method was used for the unsteady problem, while impacts of air velocity and PCM location on the flow field, thermal pattern variations and phase change dynamics were evaluated. Three different locations of the PCM were considered while air velocity was also varied during the simulation. Thermal field variations and cooling performance of the system for different PCM location scenarios were compared.

It was observed that the installation of the PCM has significant impacts on the vortex formation, thermal field variation within the system and its performance. The left, right and top wall installation of the PCM changed the thermal patterns near the heat cell of the data centre. The phase change process is fast for the upper wall installation of the PCM, while the discrepancy of the melt fraction dynamics between different air flow at this position is minimum. The case where PCM placed in the upper wall at the highest air velocity is the best configuration in terms of heat storage. The utilization of PCM and changing its locations provide an excellent tool for thermal management and cooling performance of data centre.

Results of this study can be used for initial design and optimization of cooling systems for thermal management of data centers while the importance of the high-performance computing becomes very crucial for the advanced simulations in different technological applications.

The purposes of this paper is to segment spectators of collegiate football game using a cluster analysis and to determine differences between spectator clusters based on motivations, satisfaction, and demographic characteristics.

A survey instrument was utilized, and a total of 407 usable data were gathered through a convenience sampling method at a main campus in the Southern USA. A discriminant analysis was employed to create cluster profiles including demographic variables not previously included in the clustering procedure. Cluster analysis is a procedure used to determine best group segmentation.

Through a factor-cluster analysis, two distinct groups are identified as attendees of collegiate football games: far-away fans and seasoned sideliners. Knowing the different spectators in event attendance allows marketers of collegiate sport events to effectively target segments and attract larger numbers of visitors to each event. Although the results indicated lower satisfaction with the far-away fans cluster, they are nonetheless spending their money at these events. A concerted effort to better welcome tourists that are supporting the visiting team may help boost their image of the local community and thus increase their spending level.

The current study adds to the literature on sport event research, while providing great insight for researchers and practitioners how to segment their target market. Therefore, it is believed that the results of the present study will help future researchers and industry practitioners make use of the implications and findings to broaden their knowledge about sport marketing.

The purpose of this paper is to investigate screen-printed high-frequency (HF) antennas for radio frequency identification (RFID) on-metal transponders in which a magnetic sheet was used as a substrate material.

A transponder antenna was designed in the form of square coil using a high-frequency electromagnetic software. Then, the antenna was fabricated with screen printing technique on two different magnetic sheets (RFN4 and RFN7) and on polyethylene naphthalate (PEN) foil for comparison. Its printing was carried out with polymer pastes based on silver flakes (PM-406 and SF). Thickness, track width and spacing were examined for the antennas using digital microscope and contact profilometer. Resistance and inductance were also measured, and resonant frequency, quality factor and target values of capacitance to achieve resonant frequency of the tested antenna at 13.56 MHz were calculated. Finally, RFID chips were mounted to the prepared antennas using an isotropic conductive adhesive, and a maximum read distance was measured with a reader installed in a smartphone.

It was found that an antenna thickness on the magnetic sheets used was higher than on PEN foil. At the same time, surface roughness of the fabricated antennas on these sheets was revealed to be higher as well. Inductance of the measured antennas exhibited good conformity with the antenna design, but higher divergence was noticed in the measured resistance. Its lowest value was achieved when the antenna was printed with the paste PM-406 on PEN foil and the highest one when it was fabricated with the paste SF on the same substrate. This suggests that high attention needs to be paid to a polymer paste selected for antenna printing. The performed tests showed that the magnetic sheet RFN4 seems to be better substrate for on-metal transponders compared to RFN7 due to lower resistance and higher quality factor of the prepared antennas.

Further investigations are required to examine mechanical and thermal durability of the HF antennas printed on the magnetic sheets.

The investigated HF antennas fabricated on magnetic sheets can find application in near field communication (NFC) transponders designed to be placed on metallic surfaces, e.g. on frames of advertising screens.

Influence of used magnetic sheets and polymer pastes on geometry and electrical properties of HF antennas for RFID on-metal transponders was investigated. The presented investigations can be interesting for NFC/RFID designers who are involved in designing systems suitable for metallic surfaces.

The purpose of this study is to develop a better theoretical and empirical understanding of the causal and contextual mechanisms explaining the relationship between customer orientation and business performance.

A three-stage least squares model was used on a sample of 3,720 French firms with 20 or more employees.

By using a moderated mediation approach, it was found that the mediating effect of environmental customer innovation on the relationship between customer orientation and business performance under different contextual factors (market environment, firm size and sector of activity) can be significantly stronger or weaker.

This analysis is restricted by the choice of one particular country, and further research should use data from other countries to develop a general understanding of the issues examined. Additionally, examining relevant mechanisms other than firm performance measures will advance the understanding of the customer orientation–firm performance linkage. Because of the fact that the majority of variables used are binary and that each survey was conducted in a particular situation and in a particular context, the picture portrayed could be biased. Because environmental issues not only concern consumers but also all other market actors, it would be highly useful to verify the obtained results using broader concepts such as Hult’s (2011) “market orientation plus” concept or the “sustainable market orientation” developed by Mitchell et al. (2010).

According to the results, to achieve market success and sustain a competitive advantage, managers must simultaneously invest in customer orientation and innovation performance. Additionally, managers should consider market environment, firm size and sector of activity as important contingencies in their decision of whether to invest in customer orientation.

This study makes an important contribution by opening up a “black box” and offers a deeper perspective on how and why customer orientation affects firm performance. In particular, rather than providing separate analyses of mediating and moderating effects, this study proposes a simultaneous analysis that reveals how and under what conditions customer orientation improves business performance.

This study aims to analyse the non-linear losses of a porous media (stack) composed by parallel plates and inserted in a resonator tube in oscillatory flows by proposing numerical correlations between pressure gradient and velocity.

The numerical correlations origin from computational fluid dynamics simulations, conducted at the microscopic scale, in which three fluid channels representing the porous media are taken into account. More specifically, for a specific frequency and stack porosity, the oscillating pressure input is varied, and the velocity and the pressure-drop are post-processed in the frequency domain (Fast Fourier Transform analysis).

It emerges that the viscous component of pressure drop follows a quadratic trend with respect to velocity inside the stack, while the inertial component is linear also at high-velocity regimes. Furthermore, the non-linear coefficient b of the correlation ax + bx² (related to the Forchheimer coefficient) is discovered to be dependent on frequency. The largest value of the b is found at low frequencies as the fluid particle displacement is comparable to the stack length. Furthermore, the lower the porosity the higher the Forchheimer term because the velocity gradients at the stack geometrical discontinuities are more pronounced.

The main novelty of this work is that, for the first time, non-linear losses of a parallel plate stack are investigated from a macroscopic point of view and summarised into a non-linear correlation, similar to the steady-state and well-known Darcy–Forchheimer law. The main difference is that it considers the frequency dependence of both Darcy and Forchheimer terms. The results can be used to enhance the analysis and design of thermoacoustic devices, which use the kind of stacks studied in the present work.

Special and differential treatment (SDT) in the World Trade Organisation (WTO) has failed to integrate developing countries into the international trading system, as contemplated by the WTO Agreement, itself. This paper aims to interrogate the current application of SDT by WTO members as the possible undermining factor for SDT not delivering on its objective.

The research uses a qualitative legal methodology. This study conducts desk analysis of primary legal materials and existing literature to assess current reflections of SDT and draw lessons for reforms in the WTO.

From interrogating current SDT practice in the WTO and a comparative analysis with a similar differential treatment under the Montreal Protocol, this paper finds that indeed, the problem lies in the current approach to SDT application in the WTO. This study finds that the existing absence of eligibility criteria for determining access to SDT by countries is the core reason for the abuse and sub-optimal outcome from its application.

While making a case for a rules-based approach to differentiation in the WTO, this paper proposes a unique methodology for differentiating between developing countries for SDT, including the use of a composite indicator to ensure that indicators that are used sufficiently reflect their heterogeneous needs. Drawing inspiration from Gonzalez et al. (2011a), this study introduces an adaptation for selecting a threshold for graduation. Specifically, the proposal on the value of the standard deviation of countries from the weighted mean of the composite indicator as the threshold for graduating countries from SDT is novel.