In this issue

Software Quality Journal -     

Technology invention and adoption in residential energy consumption: A stochastic frontier approach

In this paper we analyse the electricity consumption of a set of four traditional ‘white goods’ in a panel of ten EU countries observed over the period 1995–2013 with the aim of disentangling the amount of technical efficiency from overall energy saving using a stochastic frontier approach. The efficiency trend is modelled as a function of energy efficiency policies and innovation dynamics that combines invention and adoption processes using specific patents weighted by granular production data and worldwide bilateral import flows. Our model also accounts for potential endogeneity arising when innovation processes and economic growth are considered. With this replicable approach, the stochastic frontier framework allows for explicit modelling of innovation processes. Our results show that the efficiency component is related to changes in the energy efficient technological content of appliances. The ‘international’ component represents a predominant share of technological advancement and exerts a significant influence on the transient efficiency. Our evidence calls for an active role to be played by policy makers in focusing on innovation and trade policies in order to achieve more ambitious energy efficiency targets.     

Activation of timber surfaces by flame and corona treatments to improve adhesion

Long-term durability of a structural adhesive joint is an important requirement, because it has to be able to support the required design loads, under service conditions, for the planed lifetime of the structure. One way of improving bond durability is through the use of surface treatments prior to bonding, which will activate the adherends’ surface, making it more receptive to the adhesive. In this study, the effects of two surface pre-treatments (corona discharge and flame ionization) on three timbers (maritime pine, iroko, and European oak) were evaluated quantitatively through contact angle measurements. These measurements allowed the determination of the changes in the timber surface thermodynamic characteristics, thus indicating which pre-treatment performed better. The results showed that both techniques increased each timber's surface free energy, which could translate into a durability enhancement of bonded joints. Overall, the corona-discharge treatment looks more promising, since this treatment leads to a bigger increase in the timber's surface energy, especially in its polar component, whilst also tended to be less species specific, less susceptible to variation, and the treatment effects lasted longer for this type of treatment.     

The combined effect of melt stirring and ultrasonic agitation on the degassing efficiency of AlSi9Cu3 alloy

The combined effect of high intensity ultrasound and melt stirring on the degassing of AlSi₉Cu₃ using simultaneously the novel MMM (Multi-frequency Multimode Modulated) ultrasonic technology to promote cavitation, and low frequency mechanical vibration to induce melt stirring, was studied. On a first stage single low frequency mechanical vibration experiments were carried out in water in order to visualize and characterize its individual effect on the liquid dynamics. On a second stage ultrasonic vibration combined with different mechanical vibration frequencies, melt temperatures and processing times were tested in liquid AlSi₉Cu₃ alloy and their influence on the degassing efficiency was evaluated and compared with the results of the single MMM ultrasonic degassing technique. Fixed ultrasonic parameters (frequency and electric power) were used, according to the best results obtained in former experimental works developed by the authors. For the experimental conditions used in this research, it was found that melt stirring significantly improves degassing efficiency, and such improvement depends on the metal temperature and the mechanical vibration frequency. The experimental results suggest that combining melt agitation and ultrasonic vibration it is possible to achieve almost the aluminum alloy theoretical density without increasing the processing time.     

Large-vocabulary Data-centric Dialogues

Data-centric speech dialogues using large-vocabulary speech have been investigated at BT Laboratories for some time now. The research to data has been focused on applications such as directory access, customer identification, auto-attendant and transaction completion. General lessons have been learned which are applicable to many goal-seeking dialogues where the vocabulary of the task is defined by the data sought. Several trials have been run which have provided evidence of good dialogue design principles. This paper presents a framework for the dialogue design of such services, discussing topics such as mixing spelling with spoken entry and the issues of confirmation and offering of information. In addition, the difficulties of designing for confusions due to homophones and synonyms have also been addressed.     

Excited state positronium collisions with helium

Calculations of the discrete positronium (Ps) transition Ps(2s) → Ps(2p) in collisions with ground state helium are reported. Results are presented at total and single differential levels. Calculations are made within the first born approximation (FBA). The Hartley-Walters approximation is used to sum over all possible final excited atom states. In addition, impulse approximation (IA) calculations are reported for Ps(2s) and Ps(2p) fragmentation collisions with ground state helium, where the atom does not change state. Again, the FBA with the HWA is used to account for collisions in which the atom is excited or ionized.