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Dataset for Investigation of InGaN facet-dependent non-polar growth rates and composition for core-shell LEDs
No full textThis dataset contains the results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements carried out on core-shell nanostructures. The samples are highly regular arrays of GaN plasma etched cores onto which thick InGaN layers were grown using different metal organic vapour phase epitaxy (MOVPE) growth parameters.
Three different InGaN growth conditions were considered with the following parameters: 750°C at 300 mbar, 700°C at 300 mbar and 750°C at 100 mbar. Statistical growth rates were determined on the non-polar crystal planes from measurements of increase in diameter using SEM images. TEM analysis was carried out on a single nanorod for greater detail.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 at constant magnification of 6000x from 5 samples, corresponding to a plasma etched GaN template, a GaN regrowth and three InGaN growths. Approximately 80 individual nanorods and their diameters are identified in each image.
Each image was processed by binary threshold and low pass filter in Vision Assistant 2011 to obtain individual nanorod dimensions as detailed in the *.xls files. Each xls file contains separate columns for object number, calibrated area, equivalent disk diameter and image area. Statistical distributions of diameters were determined.
A planar cross section was prepared for TEM measurements using a focused ion beam to thin down the cross section to 100-200 nm thickness.
A Tecnai Osiris scanning-TEM (STEM) operating at 200 kV was used to obtain a high-angle annular dark-field (HAADF) Z-contrast image. The same image processing as in the SEM images was used to determine diameters and InGaN shell thickness.Hitachi S-4300 scanning electron microscope (SEM)
Focused Ion Beam (FIB) etching and platinum deposition
Tecnai Osiris scanning transmission electron microscope (STEM
Low-loss single-mode performance in anti resonant hollow-core fibers
No full textAll data for the results of publication1. Fibre attenuations measurement
The fibre attenuations were measured by the cutback measurement. A tungsten lamp was used as the light source. A short piece of single-mode optical fibre (SMF28, less than 0.5 m) was used to couple light from the light source into hollow core fibres (HCFs). A optical spectrum analyser (ANDO aq-6315b) was used to record the spectra before and after the cut-back.
The coupling between SMF28 and light source was free space. The other end of SMF28 approached to HCF as close as possible. The near field patten of output of HCF was monitored by a CCD camera (DMK 41BU02). While moving SMF28 across HCF end, the output mode pattern changed with the intensity. When the output pattern became most fundamental-mode like with the highest intensity, SMF28 was fixed in place through the cutback measurement.
2. Mode excitation
The mode excitation in HCFs was recorded by CCD camera while 2D scanning the butt-coupling between SMF28 and HCFs as described in 1. Fibre attenuation measurement.
3. S2 measurement
S2 measurement in the manuscript adopted the same methodology described in J. W. Nicholson, A. D. Yablon, S. Ramachandran, and S. Ghalmi, "Spatially and spectrally resolved imaging of modal content in large-mode-area fibers," Opt. Express 16, 7233-7243 (2008).
A home-made supercontinuum light source was used as the whitelight source. YOKOGAWA AQ6370D optical spectrum analyser was used to record the spectral fringes. LABVIEW program controlled the XY stage at the imaging plane of HCF output. The XY stage was made by two translation stages PI M-126.DG1 and THORLABS ZST
Dataset for "Structure of inactive states of a binary Lennard-Jones mixture"
No full textTrajectory and structural analysis data for inactive states of a glassy system of Lennard-Jones particlesFurther details available in the associated paper: D. Coslovich and R. L. Jack, J. Stat. Mech. (2016) 074012
Data for "Suppression of lattice thermal conductivity by mass-conserving cation mutation in multi-component semiconductors"
No full textIn semiconductors almost all heat is conducted by phonons (lattice vibrations), which is limited by their quasi-particle lifetimes. Phonon-phonon interactions represent scattering mechanisms that produce thermal resistance. In thermoelectric materials, this resistance due to anharmonicity should be maximised for optimal performance. We use a first-principles lattice-dynamics approach to explore the changes in lattice dynamics across an isostructural series where the average atomic mass is conserved: ZnS to CuGaS2 to Cu2ZnGeS4. Our results demonstrate an enhancement of phonon interactions in the multernary materials and confirm that lattice thermal conductivity can be controlled independently of the average mass and local coordination environments
Molecular Weight Cut-Off Determination of Organic Solvent Nanofiltration Membranes Using Poly(propylene) Glycols
No full textDataset relating to Journal Article
A new method for determining the molecular weight cut-off (MWCO) of an organic solvent nanofiltration (OSN) membrane has been developed utilising poly(propylene) glycol (PPG) oligomers. This new MWCO method overcomes the limitations of the currently popular methods: namely the high molecule cost in the popular polystyrene method, the Donnan Exclusion effects when using dye molecules and the solvent compatibility and HPLC separation resolution limitations of the lesser used poly(ethylene) glycol (PEG) method. A new reverse phase high-performance liquid chromatography separation with evaporative light scattering detection (ELSD) allows the concentration of each oligomer of PPG to be accurately determined and from this the MWCO curves are constructed. The method has a high resolution (size increment of 58 g mol-1 corresponding to the OCH(CH3)CH2 structural unit) and can be used in polar, polar aprotic, and non-polar solvents. The accuracy of the method has been demonstrated in three different solvents (methanol, acetone, and toluene) and 5 different OSN membranes (DuraMemTM 150, 200, 500, PuraMemTM 280 and StarMemTM 240). Other advantages include; oligomers of PPG are cheap and widely available, can probe a wide range of MWCO and provide high resolution MWCO curves. Consequently, it is proposed that that this method be adopted as a new standard MWCO test for OSN membranes.Tripropylene glycol (Alfa Aesar), PPG 400 (Alfa Aesar), PPG 725 (Sigma Aldrich), PPG 1000 (Alfa Aesar) of reagent grade were used as the PPG oligomer samples. Organic solvents (HPLC grade) methanol, acetone, acetonitrile and toluene were purchased from VWR and used as received. The membranes used in this study were purchased from Evonik (UK) (DuraMemTM 150, DuraMemTM 200, DuraMemTM 500 and PuraMemTM 280) and Membrane Extraction Technologies (StarMemTM 240). Ultrapure water (18.2 MΩ·cm at 25 °C) and HPLC grade acetonitrile (Alfa Aesar) were used in the gradient elution of the HPLC method. Nitrogen (BOC, 99.998 %) was used as carrier gas for the ELSD.
To determine the MWCO of the commercial OSN membranes, filtration experiments were conducted using a stainless steel dead end filtration cell (HP4750, Sterlitech Corporation USA; active membrane surface area of 14.6 cm2). A magnetic stirrer just above the membrane surface was used for mixing of the feed and minimizing concentration polarization. Typically, solutions of PPG were made up by dissolving 4 g of each PPG sample (tripropylene glycol, 400, 725, 1000) in 1 L of solvent. Before use, membranes were conditioned with the appropriate solvent at the desired applied pressure and temperature for around 2 hours until a consistent flux was achieved. For each experiment a fresh membrane was used to avoid any effects of cross contamination of samples. To perform the MWCO determination, 40 mL of feed was added to the cell of which half was permeated using an applied pressure of 30 bar, except for DuraMemTM 500 where an applied pressure of 10 bar was used. The temperature was maintained at 30 ºC using a water bath.
Determination of the concentration of each PPG oligomer in the feed, permeate and retentate was conducted using reverse phase high-performance liquid chromatography (HPLC) equipped with an evaporative light scattering detector (ELSD). An Agilent Technologies (1260 Infinity) HPLC system consisting of a quaternary pump (G1311B), autosampler (G1329B), column oven (G1316A) and ELSD (GB1530001) was equipped with a Poroshell 120 EC-C18 (4.6 x 50 mm 2.7 μm) column to achieve separation.
Before analysis, all samples in water miscible solvents were diluted with water by 1/3 (400 μL sample and 800 μL water) to give an improved chromatogram as this reduces fronting of the peaks and gives an improved baseline. Non-polar solvents were evaporated in vacuo and replaced with an equal amount of methanol. This mixture was then diluted with water as above before HPLC analysis.
Further details can be found in (J. Membr. Sci., 2017, 526, 221-228.
Dataset for Using graphene oxide as a sacrificial support of polyoxotitanium clusters to replicate its two-dimensionality on pure titania photocatalysts
No full textThe nanostructure optimisation of metal oxides is of crucial importance to exploit their qualities in artificial photosynthesis, photovoltaics and heterogeneous catalysis. Therefore, it is necessary to find viable and simple fabrication methods to tune their nanostructure. Here we reveal that graphene oxide flakes, known for their nano- and two-dimensionality, can be used as a sacrificial support to replicate their nano- and two-dimensionality in photocatalytic titania. This is demonstrated in the calcination of Ti16O16(OEt)32 polyoxotitanium clusters together with graphene oxide flakes, which results in pure titania nanoflakes of <10 nm titania nanoparticles in a two-dimensional arrangement. These titania nanoflakes outperform the titania prepared from only Ti16O16(OEt)32 clusters by a factor of forty in the photocatalytic hydrogen production from aqueous methanol suspensions, as well as the benchmark P25 titania by a factor of five. These outcomes reveal the advantage of using polyoxotitanium clusters with graphene oxide and open a new avenue for the exploitation of the vast variety of polyoxometalate clusters as precursors in catalysis and photovoltaics, as well as the use of graphene oxide as a sacrificial support for nanostructure optimisation.Details of the methodology used can be found in the associated paper
The causal role of breakfast in energy balance and health: a randomized controlled trial in obese adults
No full textBackground: The causal nature of associations between breakfast and health remain unclear in obese individuals.
Objective: To conduct a randomized controlled trial examining causal links between breakfast habits and components of energy balance in free-living obese humans.
Design: The Bath Breakfast Project is a randomized controlled trial with repeated-measures at baseline and follow-up amongst a cohort in South-West England aged 21-60 y with Dual-Energy X-Ray Absorptiometry (DXA)-derived fat mass indices ≥13 kg·m-2 (women; n=15) and ≥9 kg·m-2 (men; n=8). Components of energy balance (resting metabolic rate, physical activity thermogenesis, DIT, energy intake) were measured under free-living conditions with random allocation to daily breakfast (≥700 kcal before 1100 h) or extended fasting (0 kcal until 1200 h) for 6 weeks, with baseline and follow-up measures of health markers (e.g. hematology/adipose biopsies).
Results: Breakfast resulted in greater physical activity thermogenesis during the morning than when fasting during that period (difference:188 kcal·d-1; 95%CI=40, 335) but without any consistent effect on 24-h physical activity thermogenesis (difference:272 kcal·d-1; 95%CI= -254, 798). Energy intake was not significantly greater with breakfast than fasting (difference:338 kcal·d-1; 95%CI=-313, 988). Body mass increased across both groups over time but with no treatment effects on body composition nor any change in RMR (stable within 8 kcal·d-1). Metabolic/cardiovascular health also did not respond to treatments, except for a reduced insulinemic response to OGTT over time with daily breakfast relative to an increase with daily fasting (p=0.05).
Conclusions: In obese adults, daily breakfast causes greater physical activity during the morning, whereas morning fasting results in partial dietary compensation (i.e. greater energy intake) later in the day. There were no differences between groups in weight change and most health outcomes but insulin sensitivity was increased with breakfast relative to fasting.
Note on this version: This version includes a corrected spreadsheet - cells G14 - G24 had incorrect values in the first version of this dataset
Dataset for moment redistribution in FRP-strengthened RC members
No full textThis dataset holds the data files used to generate the figures of the article:
Tajaddini, A., Ibell, T., Darby, A., Evernden, M., and Silva, P. (2016). "Prediction of Capacity for Moment Redistribution in FRP-Strengthened Continuous RC T-Beams." J. Compos. Constr. , 10.1061/(ASCE)CC.1943-5614.0000719 , 04016066
Dataset for "The effect of age on technique variability and outcome variability during a leg press"
Get PDFPower, velocity and lower-limb joint coordination variability dat
X-ray data for coupons: AM1_Lam16_001, AM1_Lam16_007, AM1_Lam16_008 and AM1_Lam16_0013 (IMPACT)
No full textDetails about this dataset are available from the main record: https://doi.org/10.15125/BATH-0019
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