Roger Penlington

The potential of thermophotovoltaic heat recovery for the glass industry

This paper aims to provide an overview of heat recovery by thermophotovoltaics (TPV) from industrial high‐temperature processes and uses the glass industry in the UK as an example. The work is part of a study of potential industrial applications of TPV in the UK being carried out by the Northumbria Photovoltaics Applications Centre. The paper reviews the relevant facts about TPV technology and the glass industry and identifies locations of use for TPV. These are assessed in terms of glass sector, furnace type, process temperature, impact on the existing process, power scale and development effort of TPV. Knowledge of these factors should contribute to the design of an optimum TPV system. The paper estimates possible energy savings and reductions of CO2 emissions using TPV in the glass industry.

Perceptions and their influences on approaches to learning

Abstract This paper aims to highlight the importance of considering students’ perceptions of and approaches to undergraduate engineering education. Whilst considering techniques to maximise the retention of engineering students, it is also posited that understanding how students perceive their learning contexts at university is vital. It is also essential that we understand how these perceptions influence students’ approaches to their studies. This paper builds on existing research which takes a discipline focus to a discussion of the relationships linking quality of learning with generic research into approaches and perceptions of teaching and learning. It discusses an ongoing research project which is making use of a mixed methods research platform to investigate the complex nature of students’ perceptions and approaches. It is presented as a valuable methodology for adoption by engineering education researchers. The research is based on an exploratory sequential mixed methods design where the qualitative data is dominant. Initial analysis of the data collected during the pilot phase, supported by relevant literature, has been used to identify areas of the learning context which appear to influence students’ approaches to the engineering modules involved in the study. Some of the emerging themes are discussed in this paper with consideration for the impact on the teaching of engineering.

Interaction effects between surface radiation and double-diffusive turbulent natural convection in an enclosed cavity filled with solid obstacles

The work reported here is a 2D numerical study on the buoyancy-driven low speed flow of humid air inside a rectangular cavity partially filled with solid cylindrical objects and whose vertical walls are maintained at 1.2 and 21 oC. This is a case of double diffusion where both temperature and concentration gradients are significant. Detailed calculations were carried out and results compared with reliable data, with the aim of investigating the influence of surface emissivity on heat and moisture transport. The Rayleigh number of the fluid mixture (air and water vapour) based on the height of the vertical wall is found to be 1.45 x 109. In the computations, turbulent fluxes of the momentum, heat and mass were modelled by low-Re (Launder-Sharma) k-e eddy viscosity model. The effect of radiation has been found to be significant even for the moderate temperature difference of 19.8 oC between the hot and the cold walls with the humid air participating in the radiation heat transfer. Variations of average Nusselt number and buoyancy flux are analysed and profiles of turbulent quantities are studied in order to observe the net effect of the intensity of turbulence. It has been found that a change in surface emissivity influences the humidity distribution and heat transfer within the cavity. It was also observed that during natural convection process the air/water vapour combination results in an increase in the heat transfer as compared to pure natural convection. An increase in heat transfer is observed using thermo-physical materials of higher surface emissivity. It can thus be implied that with the appropriate choice of components, the fluid flow, heat and mass transfer due to natural convection can be increased passively.

Laser Trimming of CuAlMo Thin-Film Resistors:Effect of Laser Processing Parameters

This paper reports the effect of varying laser trimming process parameters on the electrical performance of a novel CuAlMo thin-film resistor material. The films were prepared on Al2O3 substrates by direct-current (DC) magnetron sputtering, before being laser trimmed to target resistance value. The effect of varying key laser parameters of power, Q-rate, and bite size on the resistor stability and tolerance accuracy were systematically investigated. By reducing laser power and bite size and balancing this with Q-rate setting, significant improvements in resistor stability and resistor tolerance accuracies of less than ±0.5% were achieved.

Laser Trim Pattern Optimization for CuAlMo Thin-Film Resistors

The influence of varying laser trim patterns on the electrical performance of a novel CuAlMo thin-film resistor material is investigated. The benefits and limitations of various trim geometries are considered before two patterns, the “L” cut and serpentine cut, are selected to laser-trim resistor samples to target values of 1-10 Ω, using previously optimized laser conditions. The effect of increasing trim gain and varying trim pattern on the stability and standard deviation of the films is then systematically investigated. A two-stage trimming process is used to reduce resistance drift to <;0.1% following storage for 168 h at 125°C in air, which also allows much tighter resistance tolerances of <;±0.1% to be achieved.

Design of educational systems for work based learning (WBL): the learner experience

Purpose – Information and communication technologies have transformed higher education providing e‐mechanisms to support the delivery of content, communication and interaction. One example is the widespread adoption of virtual learning environments (VLEs) by higher education institutions to provide a key interface among learners, the content and tutors. The aim of this paper is to explore the effectiveness of the design of educational systems for work based learning (WBL) from the learners perspective. The study includes consideration of the use of technology to support the work based learning process for the learner.Design/methodology/approach – Case studies from four postgraduate programmes and one undergraduate programme within the School of Computing, Engineering and Information Sciences (CEIS) at Northumbria University are presented. Key results from a survey of students on these programmes are discussed.Findings – The results demonstrate that there are different motivations for this type of provisi...

Application of advanced coatings to narrow neck press and blow plungers in the glass container industry

Wear and failure modes exhibited by narrow neck press and blow (NNPB) plungers in the glass container industry have been related to inappropriate material selection. Problems exist with substrate and coating materials which lead to machine down time, process instability and poor product quality. Previous attempts to improve the service life of NNPB plungers have not examined the process operating characteristics and demanding nature of the application. New substrate and coating materials have been utilized and an assessment of their suitability for this application examined. Initial results from plant trials with modified plungers suggest that improvements in operational performance are achievable. This application, and other components of the mould tooling set, may benefit from improvements which may increase tool life and reduce the problems which result from the application of lubricant dopes to glass contact surfaces.

Effect of Emissivity on the Heat and Mass Transfer of Humid Air in a Cavity Filled with Solid Obstacles

The work reported here is a 2D numerical study on the buoyancy-driven low-speed turbulent flow of humid air inside a rectangular cavity partially filled with solid cylindrical objects for a Rayleigh number of 1.45 × 109. Variations of Nusselt number, buoyancy flux, vapor mass fraction, and turbulence viscosity ratio are presented for various emissivity values of wall surfaces. It was observed that during the natural convection process, radiation effects are very significant and the air/water vapor combination results in a small increase in heat transfer as compared with the pure natural convection of dry air.

A new trimming approach for shunt resistors used in metering applications

A growing number of smart energy meters and electric charging stations have sparked a demand for a high precision, low value shunt resistors to measure the flow of electrical current. This paper investigates the possibility of trimming 100 micro ohms Manganin shunt resistors with tolerance of 5 percent to improve their accuracy and performance for use in smart energy meters. In theory, reducing the standard 5 percent tolerance of the shunt resistors can be achieved by removing controlled amounts of the resistive material. In this experiment, theoretical analysis is carried out to determine the maximum amount of resistive material that can be removed from Manganin shunt resistor to reduce its standard tolerance of 5 percent. Two alternative designs are then used to trim the material from the Manganin strip using machining techniques. Implications of the experimental results to the flow of electrical current and temperature rise in the shunt resistors are discussed. Results from the initial trimming trials show that the standard tolerance of 5 percent can be reduced to less than 1 percent.

Heat Transfer Modelling of Glass Media within TPV Systems

Understanding and optimisation of heat transfer, and in particular radiative heat transfer in terms of spectral, angular and spatial radiation distributions is important to achieve high system efficiencies and high electrical power densities for thermophtovoltaics (TPV). This work reviews heat transfer models and uses the Discrete Ordinates method. Firstly one‐dimensional heat transfer in fused silica (quartz glass) shields was examined for the common arrangement, radiator‐air‐glass‐air‐PV cell. It has been concluded that an alternative arrangement radiator‐glass‐air‐PV cell with increased thickness of fused silica should have advantages in terms of improved transmission of convertible radiation and enhanced suppression of non‐convertible radiation.