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Automatic Design Structure Matrices: A Comparison of Two Formula Student Projects
No full textThis data archive contains the underlying data for the conference publication entitled "Automatic Design Structure Matrices: A Comparison of Two Formula Student Projects". The paper has been published in the conference proceedings of the International Conference on Engineering Design.
The paper presents the comparison of Design Structure Matrices from two Formula Student teams that have been automatically generated from the monitoring of the co-occurrence of updates to the product models. These product models were stored on a shared network drive. A software tool developed by the author was used to monitor the changes to these files.
The underlying data and a README file is contained within this archive
Dataset for "Optical properties and resonant cavity modes in axial InGaN/GaN nanotube microcavities"
No full textThis dataset contains scanning electron microscopy (SEM) images, Catodoluminescence (CL), MicroPL and Confocal PL measurements and Finite-Difference Time-Domain (FDTD) simulations carried out on InGaN/GaN nanotube microcavities. The samples were fabricated via a combination of Displacement Talbot Lithography for patterning and inductively coupled plasma top-down dry-etching. SEM imaging were used to assess first, the patterning of SiNx mask, and second, the InGaN/GaN nanotube morphology and dimensions. CL were used to assess the optical properties of individual InGaN/GaN nanotube. MicroPL and Confocal PL were used to carry out continuous excitation at room temperature of isolated InGaN/GaN nanotube. FDTD simulations were used to investigate the nature of the resonant modes. Correlation between PL techniques and FDTD simulation suggests that both mixed whispering gallery – Fabry-Perot cavity modes are observed within the single nanotube.Secondary electron images were captured using a Hitachi S-4300 scanning electron microscope (SEM). An accelerating voltage of 5 kV was used to collect the images.
Cathodoluminescence hyperspectral imaging measurements were carried out at room temperature in a modified FEI Quanta 250 field emission SEM using electron energies of 5.0 keV and beam currents of approximately 1 nA. Light was collected using an NA 0.28 reflecting objective with its axis perpendicular to the electron beam and focused directly on the entrance of the spectrograph using an off-axis paraboloidal mirror. We used a 125 mm focal length spectrograph with a 600 lines/mm grating and 50 μm entrance slit, coupled to a cooled electron multiplying charge-coupled device (EMCCD) detector.
µPL characterization was carried out on single nanotube cavities in an in-house made micro-PL system. A 375 nm continuous wave (CW) laser diode was used to selectively excite the InGaN/GaN SQW. A 50x magnification, 0.43 NA objective was used to focus the excitation laser down to ~ 2μm and collect the emission through a 1 mm fibre bundle. A 0.55 m Jobin Yvon spectrometer (iHR550) was used to disperse the emission and the emission was detected with an air-cooled charge coupled device (CCD). The system was equipped with X-Y-Z motorized stages allowing to selectively excite single nanotubes. All the measurements were performed at room temperature.
Confocal PL characterization was performed using a commercial WITec confocal microscope. A 375 nm continuous wave (CW) diode laser was used as an optical pumping source and the system was equipped with a 300 mm Princeton instruments monochromator (SP2300i) and an air-cooled charge coupled device (CCD). An objective lens (100×, NA=0.95) was used to focus the laser beam down to a spot with a diameter of ~400 nm. The emission was dispersed by the monochromator with a resolution of ~0.1 nm. An optical fiber with a diameter of 10 µm acted as a pinhole, thus allowing the emission to be collected from only where the sample was excited. The system was equipped with a high-resolution x-y-z piezo-stage to individually address and examine single nanotubes. The spatial resolution of the system was ~ 160 nm. All the measurements were performed at room temperature.
A three-dimensional finite difference time domain (FDTD) approach has been used to simulate the nanotube structure using commercial-grade software [Lumerical Solutions, Inc. http://www.lumerical.com/tcad-products/fdtd/]. A dipole source with emission wavelengths from 370 to 720 nm was vertically positioned in the plane of the nanotube quantum wells and centred within the width of the walls. All the geometrical data used for the simulation are from the SEM measurement of our nanotube. The n-GaN, p-GaN and GaN-substrate layers are given a refractive index defined by ellipsometry measurements performed on the as-grown structure at the University of Strathclyde. The InGaN quantum well layer is 3nm thick (n=2.6). There is a minimum of fifteen mesh cells per wavelength in the simulation that is run for 2000fs. Frequency-domain power monitors have been used to record the emission profile over the simulation region, which is surrounded by perfectly matched layer absorbing boundaries on all sides. The simulated spectra are collected by a grid of 12 time-monitors placed at various points inside the nanotube structure, accurately calculating the envelope of the time-domain field signal. For the perfectly-circular higher-Q examples, each resonant peak is isolated in the frequency domain using a Gaussian filter, and by taking the inverse Fourier transforms the time decay have been calculated separately for each peak. The slope of the time decay is used to calculate the Q-factor of each resonance. In the DTL fabricated structures, the electromagnetic fields decay completely from the simulation in a time that can be simulated reasonably by FDTD. Therefore, the resonant frequencies are found from the time-monitors along with the full-width half-maximum (FWHM) of the corresponding peaks. We can then use Q=fR/Δf where fR is the resonant frequency and Δf is the FWHM.The nanotube investigated by µPL and Confocal PL were mechanically removed from the substrate in an ultrasonic bath and then dispersed on a host sapphire substrat
Data for "A rapidly-reversible absorptive and emissive vapochromic Pt(II) pincer-based chemical sensor"
No full textData to accompany the article "A rapidly-reversible absorptive and emissive vapochromic Pt(II) pincer-based chemical sensor". This dataset contains data from the computational modelling carried out as part of this study, including optimised structures and simulated optical-absorption spectra
Openness assessment of 132 open source hardware products
No full textThis is the raw data set on which the article "What is the source of open source hardware?" to be published in the Journal of Open Hardware under an open access license is based. The abstract of the article is as follows: "What “open source” means once applied to tangible products has been so far exclusively addressed through the light of licensing. While this approach is adapted for software, it appears to be over-simplistic for complex hardware products. Whether such a product can be labelled as open source is not only a question of license but also a question of documentation, i.e. what is the information that sufficiently describes it? In other words, what is the “source” of open source hardware? To date there is no trivial answer to this question, leaving large room for interpretation in the usage of the term. Based on analysis of public documentation of 132 products, this paper provides an overview of how practitioners tend to interpret the concept of open source hardware. Results empirically confirm the existence of two main usages of the open source principles in the context of tangible products: publication of product-related documentation as a means to support community-based product development and to disseminate privately developed innovations. It also underlines the high variety of interpretations and even misuses of the concept of open source hardware. This reveals in turn that this concept may not even be clear to practitioners and calls for more narrowed down definitions of what has to be shared for a product to be called open source. Results gained by the analysis of current publication practice are summarized in the definition of an open source hardware lifecycle to contribute towards this effort.
Branched ketone biofuels as blending agents for Jet-A1 aviation kerosene
No full textThe data for the fuel properties is given here. Each tab in the excel sheet gives a different fuel property. The same product codes as in the main manuscript are used.Fuel properties were measured (flash point, viscosity, melting point) by using the appropriate measurement and recording in excel (given here
Wastewater monitoring data 2011-2016
No full textThe Sewage Biomarker Analysis for Community Health Assessment project analysed wastewater in over 60 European cities and towns (hereinafter referred to as ‘cities’) to explore the drug-taking habits of those who live in them. The results provide a valuable snapshot of the drug flow through the cities involved, revealing marked geographical variations
Data for Quantitative characterisation of imaging fibres
No full textImages, code and data used to produce the figures in the paper Quantitative characterisation of imaging fibres
Growth of GaN Epitaxial Films on Polycrystalline Diamond by Metal-organic Vapor Phase Epitaxy
Get PDFHeat extraction is often essential to ensuring efficient performance of semiconductor devices and requires minimizing the thermal resistance between the functional semiconductor layers and any heat sink. This paper reports epitaxial growth of N-polar GaN films on polycrystalline diamond substrates of high thermal conductivity with metal-organic vapor phase epitaxy by using a SixC layer formed during deposition of polycrystalline diamond on a silicon substrate. The SixC layer acts to provide the necessary structure ordering information for the formation of a single crystal GaN film at the wafer scale. It is shown that a three-dimensional island (3D) growth process removes hexagonal defects that are induced by the non-single crystal nature of the SixC layer. It is also shown that intensive 3D growth and the introduction of convex curvature of the substrate can be deployed to reduce tensile stress in the GaN epitaxy to enable the growth of crack-free layer up to a thickness of 1.1m. The twist and tilt can be as low as 0.65 and 0.39 respectively, values broadly comparable with GaN grown on Si substrates with a similar structure.Description of data
All the data used in this article takes the form measurable quantity (dependent variable) versus parameter varied under operator control (independent variable) and is recorded in tabulated form in spreadsheets. Apart from one data set referred to in a “non-quantitative way”, all the data used was presented in the above article in graphical form indicated as figures 1b, 2, 3 etc. Figure 1a is a sketch and therefore does not contain measurable data. The data-containing graphs are:
Figure 1b in file Fig_1b_curvature:
The bow of both kinds of PD substrates measured by moving a digitally-controlled stylus across the sample surface over a distance of 5 mm and measuring the vertical deflection of the stylus every few microns. The PDA substrate was found to have a convex bow (~1.5 μm over 5 mm) whilst PDB had a concave bow (~6 μm over 5 mm), where convex and concave are defined in the article.
Figure 2 in file Jiang_Fig_2_xps_data:
X-ray photo-electron spectroscopy (XPS): intensity of emitted x-ray photon versus binding energy. These data reveal the nature of the chemical bonds between the elements found on the surface or immediate sub-surface layer of the samples under consideration. This in turn provides information about the chemical nature of the surface on which the III-Nitride layers were grown.
In describing the data in this graph, reference is made to energy dispersive x-ray (EDX) measurements that confirm the presence of both silicon and carbon on the surface of the nominally polycrystalline diamond growth substrates, both in large quantities. Taken together with the chemical bonding information obtained from the XPS measurements (presented in figure 2) it was inferred that almost all the silicon present was bonded chemically to carbon, with some silicon bonded to oxygen.
Figure 3 in file Jiang_Fig_3_reflectivity:
These data were collected via in-situ measurements of the intensity of a visible laser beam (typically red light) from the surface of the III-Nitride layers as they were grown using a standard commercially available tool (specified in the article). The independent variable is time.
Figure 4 in file Jiang_Fig_4_Surface_MOR:
The data are images formed by the secondary electron emission, taken by digital camera during inspection of the surface of the grown III-Nitride layer by scanning electron microscopy. The data sets in the form of the intensity reaching each pixel in a two dimensional array of such pixels in the digital camera.
Figure 5 in file Jiang_Fig_5_comparison_of_XRD_3D_GaN(0002)_and_GaN(103):
These data are the intensity of a diffracted x-ray beam measured by rocking samples 3 and 4 (described in the article, especially in Table 1) when illuminated by a beam of x-rays under conditions that reveal the twist in the III-Nitride layers [beam alignment along crystallographic direction GaN(10-13)] and the tilt [ beam alignment along GaN(0002)].
Figure 6 in file Jiang_Fig_6_E2H Raman_comparison_3D_growth_time:
Raman spectra of Sample 3 and Sample 4 in the vicinity of the E2H phonon mode for two samples to reveal the impact of the duration of the 3-diminsional growth mode on the strain in the GaN epitaxial films.
Figure 7 in file Jiang_Fig_7_Raman_comparison of growth on bowed substrates:
Raman spectra in the vicinity of the E2H phonon mode for (a) Sample 5 grown on a concave PDB substrate and (b) Sample 6 grown on a convex PDA substrate to reveal the impact on the strain in the GaN epitaxial films of the growing the III-Nitride layers on bowed substrate.Apart from the photographs the data processing involved only plotting measured dependent variable values against the corresponding measured independent variable values. Where applied, curve fitting performed by using the polynomial curve fitting tool available in Excel. Otherwise the data were not processed in any way.Two kinds of PD substrate (hereafter called PDA and PDB) from different suppliers [Element Six Ltd, Diamond Materials GmbH] were used in the work, both supplied with their initial Si(111) growth substrate intact. In each case the Si(111) was removed by immersion in hot KOH or/and isotropic Si etching solution (a mixture of HNO3 and HF). A distinguishing feature of the two types of substrate after removal of the Si(111) substrate is their curvature, as shown in Figure 1a. The curvature measured by a stylus technique (Dektak Stylus profiler), shown in Figure 1b, occurs as a result of residual stress in the PD layers [9]. PDA substrates exhibited a convex bow (~1.5 micron over 5 mm) while PDB substrates had concave bow (~6 micron over 5 mm).
X-ray photoelectron spectroscopy (XPS) measurements were performed under sub-contract at the University of Cardiff.
Energy dispersive x-ray spectroscopy (EDX) was performed a JEOL SEM6480LV electron microscope at the University of Bath.
Surface reflections were recorded during epitaxial growth of all samples using a LAYTEC EpiSense system.
X-ray diffraction (XRD) measurements were performed using a BEDE D1 system.
Raman spectroscopy was performed using a Renishaw inVia systemusing a laser source of wavelength = 530 nm).
The curvature of the substrates after epitaxial growth was measured with a Dektak stylus profiler.
All data collection was performed using the software supplied by the equipment manufacturers available at the time of purchase of the equipment.
All equipment was operated under the standard conditions recommended by the equipment manufacturers and all measurements were performed at room temperature, except the surface reflection measurements performed during epitaxial growth, which were performed at the temperatures specified in the manuscript.Sample preparation apart from the growth of the polycrystalline diamond substrates (which were supplied commercial manufacturers named in the manuscript) and epitaxial growth, was carried out in David Bullett Nanofabrication Facility at the Univesity of Bath
Study into the Kinetic Properties and Surface Attachment of a Thermostable Adenylate Kinase
No full textAbstract: A thermostable adenylate kinase (tAK) has been used as model protein contaminant on surfaces, so used because residual protein after high temperature wash steps can be detected at extremely low concentrations. This gives the potential for accurate, quantitative measurement of the effectiveness of different wash processes in removing protein contamination. Current methods utilise non-covalent (physisorbtion) of tAK to surfaces, but this can be relatively easily removed. In this study, the covalent binding of tAK to surfaces was studied to provide an alternative model for surface contamination. Kinetic analysis showed that the efficiency of the enzyme expressed as the catalytic rate over the Michaelis constant (kcat/KM) increased from 8.45 ± 3.04 mM-1 s-1 in solution to 32.23 ± 3.20 or 24.46 ± 4.41 mM-1 s-1 when the enzyme was immobilised onto polypropylene or plasma activated polypropylene respectively. Maleic anhydride plasma activated polypropylene showed potential to provide a more robust challenge for washing processes as it retained significantly higher amounts of tAK enzyme than polypropylene in simple washing experiments. Inhibition of the coupled enzyme (luciferase/luciferin) system used for the detection of adenylate kinase activity, was observed for a secondary product of the reaction. This needs to be taken into consideration when using the assay to estimate cleaning efficacy.UV-Vis Luminescence spectroscopy.
IR spectroscopy.Data worked up in Microsoft Excel and presented in Origin Graphing Software
Data for the publication: Low index contrast imaging fibers
Get PDFThis contains the images and raw data presented in the paper Low index contrast imaging fibres published in Optics Letters. The data includes the individual images used to demonstrate how the new fibres are made and the raw data used to determine the performance of the imaging fibres presented in the publication.Optical Fibre Drawing Towe
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