Simple prompts reduce inadvertent energy consumption from lighting in office buildings

Building designs regularly fail to achieve the anticipated levels of in-use energy consumption. The interaction of occupants with building controls is often cited as a key factor behind this discrepancy. This paper examines whether one factor in inadvertent energy consumption might be the appearance of post-completion errors (when an intended action is not taken because a primary goal has already been accomplished) in occupants’ interactions with building controls. Post-completion errors have been widely studied in human-computer interaction but the concept has not previously been applied to the interaction of occupants with building controls. Two experiments were carried out to examine the effect of incorporating two different types of simple prompt to reduce post-completion error in the use of light switches in office meeting rooms. Results showed that the prompts were effective and that occupants switched off lights when leaving the room more often when presented with a normative prompt than with a standard injunction. Additionally, an over reliance on PIR sensors to turn off lights after meetings was observed, which reduced their intended energy savings. We conclude that achieving low carbon buildings in practice is not solely a technological issue and that application of user-models from human-computer interaction will encourage appropriate occupant interaction with building controls and help reduce inadvertent energy consumption

Identifying behavioural predictors of small power electricity consumption in office buildings

It is widely accepted that there is a gap between design energy and real world operational energy consumption. The behaviour of occupants is often cited as an important factor influencing building energy performance. However, its consideration, both during design and operation, is overly simplistic, often assuming a direct link between attitudes and behaviour. Alternative models of decision making from psychology highlight a range of additional influential factors and emphasise that occupants do not always act in a rational manner. Developing a better understanding of occupant decision making could help inform office energy conservation campaigns as well as models of behaviour employed during the design process. This paper assesses the contribution of various behavioural constructs on small power consumption in offices. The method is based upon the Theory of Planned Behaviour (TPB) which assumes that intention is driven by three factors: attitude, subjective norms, and perceived behavioural control, but we also consider a fourth construct: habit measured through the Self- Report Habit Index (SRHI). A questionnaire was issued to 81 participants in two UK offices. Questionnaire results for each behavioural construct were correlated against each participant’s individual workstation electricity consumption. The intentional processes proposed by TPB could not account for the observed differences in occupants’ interactions with small power appliances. Instead, occupants were interacting with small power “automatically”, with habit accounting for 11% of the variation in workstation energy consumption. The implications for occupant behaviour models and employee engagement campaigns are discussed

Rapid tooling : investigation of soft-tooled micro-injection moulding process characteristics using in-line measurements and surface metrology

Purpose The purpose of this study is to demonstrate and characterise a soft-tooled micro-injection moulding process through in-line measurements and surface metrology using a data-intensive approach. Design/methodology/approach A soft tool for a demonstrator product that mimics the main features of miniature components in medical devices and microsystem components has been designed and fabricated using material jetting technique. The soft tool was then integrated into a mould assembly on the micro-injection moulding machine, and mouldings were made. Sensor and data acquisition devices including thermal imaging and injection pressure sensing have been set up to collect data for each of the prototypes. Off-line dimensional characterisation of the parts and the soft tool have also been carried out to quantify the prototype quality and dimensional changes on the soft tool after the manufacturing cycles. Findings The data collection and analysis methods presented here enable the evaluation of the quality of the moulded parts in real-time from in-line measurements. Importantly, it is demonstrated that soft-tool surface temperature difference values can be used as reliable indicators for moulding quality. Reduction in the total volume of the soft-tool moulding cavity was detected and quantified up to 100 cycles. Data collected from in-line monitoring was also used for filling assessment of the soft-tool moulding cavity, providing about 90% accuracy in filling prediction with relatively modest sensors and monitoring technologies. Originality/value This work presents a data-intensive approach for the characterisation of soft-tooled micro-injection moulding processes for the first time. The overall results of this study show that the product-focussed data-rich approach presented here proved to be an essential and useful way of exploiting additive manufacturing technologies for soft-tooled rapid prototyping and new product introduction

3D-printing of all-dielectric electromagnetic devices : challenges and opportunities

The rapid advancement of three-dimensional printing (3DP) technology has opened up new possibilities for fabricating novel functional structures with electromagnetic (EM) properties. Materials with high dielectric permittivity are of significant interest in 3D printing of devices for advanced electromagnetic applications due to their ability to enhance device performance, enable miniaturization and compact designs, offer customization and tailored properties, and provide design freedom. High dielectric permittivity materials enhance the performance of EM devices by enabling efficient energy storage and manipulation of electric fields, leading to improved functionality and increased signal processing capabilities. Furthermore, 3DP enables the fabrication of complex geometries and customized structures, and incorporating materials with high dielectric permittivity provides precise control over the electromagnetic properties, enabling the realization of advanced functionalities and designs

Fabrication of high permittivity resin composite for vat photopolymerization 3D printing : morphology, thermal, dynamic mechanical and dielectric properties

The formulation of a high dielectric permittivity ceramic/polymer composite feedstock for daylight vat photopolymerization 3D printing (3DP) is demonstrated, targeting 3DP of devices for microwave and THz applications. The precursor is composed of a commercial visible light photo-reactive polymer (VIS-curable photopolymer) and dispersed titanium dioxide (TiO2, TO) ceramic nano-powder or calcium copper titanate (CCT) micro-powder. To provide consistent 3DP processing from the formulated feedstocks, the carefully chosen dispersant performed the double function of adjusting the overall viscosity of the photopolymer and provided good matrix-to-filler bonding. Depending on the ceramic powder content, the optimal viscosities for reproducible 3DP with resolution better than 100 µm were η(TO) = 1.20 ± 0.02 Pa.s and η (CCT) = 0.72 ± 0.05 Pa.s for 20% w/v TO/resin and 20% w/v CCT/resin composites at 0.1 s−1 respectively, thus showing a significant dependence of the “printability” on the dispersed particle sizes. The complex dielectric properties of the as-3D printed samples from pure commercial photopolymer and the bespoke ceramic/photopolymer mixes are investigated at 2.5 GHz, 5 GHz, and in the 12–18 GHz frequency range. The results show that the addition of 20% w/v of TO and CCT ceramic powder to the initial photopolymer increased the real part of the permittivity of the 3DP composites from ε’ = 2.7 ± 0.02 to ε’(TO) = 3.88 ± 0.02 and ε’(CCT) = 3.5 ± 0.02 respectively. The present work can be used as a guideline for high-resolution 3DP of structures possessing high-ε

Flow rate controlled pipetting for microfluidics : second generation flexible hydraulic reservoir (FHRv2)

A critical component of microfluidic technology is the fluid pumping mechanism. Syringe and pressure pumps are typically used in the lab environment; however, their operations generate considerable dead volume that is often larger than the volume of the chip itself, leading to considerable waste of precious sample. As an alternative, pipetting allows for precise liquid dispensing with zero dead volume; however, it has a limited flow control. Recently, we have introduced a low-cost sample loading interface with zero dead-volume named flexible hydraulic reservoir (FHR). In this study, we present a second-generation FHRv2 that combines continuous pumping, zero-dead volume and the versatility of pipetting. The performance of FHRv2 is tested against a syringe pump at flow rates ranging between 20 and 60 μL/min. It demonstrated smoother operation and identical transient time to reach steady flow rate as confirmed by a mathematical model developed for the occasion. Importantly, we also demonstrate that the FHRv2 prevents sedimentation-induced artifacts typically encountered in typical syringe pumps when dispensing particles. Finally, we demonstrate the fabrication of the FHRv2 concept with injection molding using a 3D-printed mold. Overall, our FHRv2 offers a low-cost and versatile solution for zero-volume liquid handling in microfluidic devices

X-ray computed tomography for predictive quality assessment, 3D visualisation of micro-injection mouldings and soft-tool deformation

This work presents X-ray computed tomography (XCT) as a dimensional quality assurance technique for micro-injection moulded polymeric test objects for the establishment of predictive quality models and quantifying soft-tool deformation. The results are compared against an industry standard laser-scanning-confocal microscope (LSCM) for the evaluation of XCT’s capability. The work demonstrates; (i) the exploitation of a XCT equipment for dimensional characterisation of micro-injection moulded products made out of polymers with adequate acquisition times, (ii) that acquired XCT data from the 3D visualisation of the micromouldings perform on par with a laser-scanning-confocal microscope in a quality prediction model, (iii) that the deformation occurring in an additively manufactured soft-tool can be quantified using XCT. The technique was particularly superior in volumetric data acquisition compared to LSCM in the filling prediction of the micromouldings. Better accuracy and repeatability in predicting the quality of the mouldings up to 92% achieved with XCT, in conjunction with an in-line collected soft-tool surface temperature data as an indirect quality assurance method. Given the capability of the XCT for the 3D data acquisition of polymeric miniature components, the approach described here has great potential in high-value micro-manufacturing process quality modelling for in-line quality assessment of miniature and added value products in data-rich contexts