In-process measurement

"I often say that when you can measure what you are speaking about and express it in numbers, you know something about it; when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind." The above statement was made by Lord Kelvin (1824-1907) about''' hundred years ago and is reproduced as the main theme of the present paper. The only qualification that should be made is that when Lord Kelvin made the above statement he did not think that the philosophy he expounded was specially appropriate to engineering manufacture. The present paper will consider how this philosophy can b3 applied to engineering manufacture only. ...[cont.

The design of a hydrostatic lubrication arrangement for the horizontal and transverse slides of a no. 3 archdale vertical milling machine

The Department of Production and Industrial Administration of The College of Aeronautics has made a detailed analysis into the performance of numerically controlled machine tools, and this shows that when these machines are operating under light cutting loads, the total envelope tolerance is about 0.003 ins. Further investigation into the source of the errors showed that about 80 per cent of this error was due to mechanical mechanisms in the machine tool. The electronic equipment operated inside a total band of 0.0004 ins. over small distances, and 0.0006 ins. over 10 inches. This situation appeared to justify a comprehensive survey into the methods which may be used to improve the mechanical performance of these machines. After due consideration had been given to a number of possible alternatives, it was decided to fit hydrostatic lubrication to the slides, nut and screw arrangement, and the thrust bearings used on the X and Y axes of an existing No. 3 Archdale Milling Machine. The Z axis was not included in the redesign, because analysis showed that a new head casting would have been necessary. It was thought that this additional expense was not justified and that the data obtained from an examination of the performance given by the X and Y axes would show whether the system could be used with advantage in the design of new machines. The paper gives details of the calculations used to establish the dimensions of the new features fitted to the machine to satisfy the target performance conditions which appeared to be possible and are given in the introduction. The authors would like to express their appreciation to James Archdale and Co. for making a machine available for this investigation, to the Staveley Research Department, and in particular to Mr. Graham, Mr. Harris, Mr. Huntley) M r. Cummings and Mr. Hayward

Author Correction: Long-term field comparison of multiple low-cost particulate matter sensors in an outdoor urban environment

Correction to: Scientific Reports https://doi.org/10.1038/s41598-019-43716-3, published online 16 May 2019. This Article contains a typographical error in the Acknowledgements section. “Natural Environmental Research Council grant number [NE/L002531/1]” should read: “Natural Environment Research Council: NE/N012070/1”

Characterisation and calibration of low-cost PM sensors at high temporal resolution to reference-grade performance

Particulate Matter (PM) low-cost sensors (LCS) present a cost-effective opportunity to improve the spatiotemporal resolution of airborne PM data. Previous studies focused on PM-LCS-reported hourly data and identified, without fully addressing, their limitations. However, PM-LCS provide measurements at finer temporal resolutions. Furthermore, government bodies have developed certifications to accompany new uses of these sensors, but these certifications have shortcomings. To address these knowledge gaps, PM-LCS of two models, 8 Sensirion SPS30 and 8 Plantower PMS5003, were collocated for one year with a Fidas 200S, MCERTS-certified PM monitor and were characterised at 2 min resolution, enabling replication of certification processes, and highlighting their limitations and improvements. Robust linear models using sensor-reported particle number concentrations and relative humidity, coupled with 2-week biannual calibration campaigns, achieved reference-grade performance, at median PM2.5 background concentration of 5.5 μg/m3, demonstrating that, with careful calibration, PM-LCS may cost-effectively supplement reference equipment in multi-nodes networks with fine spatiotemporality

Testing Smart City environmental monitoring technology using small scale temporary cities

Exposure to Particulate Matter (PM) has been identified as a major health problem worldwide. Established measurement techniques require equipment costing many thousands of dollars and specialist expertise to maintain. Ongoing research is investigating the use of low cost <;$300 sensors to enable greater temporal-spatial density of readings to be taken. There are questions about the suitability and reliability of these low-cost sensors, which can be addressed by deploying and evaluating the sensors in real world applications. Rather than deploying standalone data loggers for each sensor, each air quality monitor is connected to an IoT device to enable real time transmission of data. We propose festival sites as small scale cities to enable a short term deployments and evaluation of sensors. This work illustrates that, if coupled with higher resolution of wind data, low-cost sensors may enable to follow the evolution of pollution hotspots and help the identification of pollution sources. This study, building upon the body of work focused on the evaluation and best practice of using low-cost sensors for PM monitoring. We present data from these IoT devices and experiences gained from using a festival site as a substitute for a city

Impaired expression of metallothioneins contributes to allergen-induced inflammation in patients with atopic dermatitis

Regulation of cutaneous immunity is severely compromised in inflammatory skin disease. To investigate the molecular crosstalk underpinning tolerance versus inflammation in atopic dermatitis, we utilise a human in vivo allergen challenge study, exposing atopic dermatitis patients to house dust mite. Here we analyse transcriptional programmes at the population and single cell levels in parallel with immunophenotyping of cutaneous immunocytes revealed a distinct dichotomy in atopic dermatitis patient responsiveness to house dust mite challenge. Our study shows that reactivity to house dust mite was associated with high basal levels of TNF-expressing cutaneous Th17 T cells, and documents the presence of hub structures where Langerhans cells and T cells co-localised. Mechanistically, we identify expression of metallothioneins and transcriptional programmes encoding antioxidant defences across all skin cell types, that appear to protect against allergen-induced inflammation. Furthermore, single nucleotide polymorphisms in the MTIX gene are associated with patients who did not react to house dust mite, opening up possibilities for therapeutic interventions modulating metallothionein expression in atopic dermatitis

Discovery of a series of 2-(pyridinyl) pyrimidines as potent antagonists of GPR40

A series of 2-(pyridinyl)pyrimidines were identified as potent GPR40 antagonists. Despite significant challenges related to improving the combination of potency and lipophilicity within the series, the compounds were optimised to identify a suitable in vivo probe compound, which was confirmed to exhibit pharmacology consistent with GPR40 antagonism

Investigation into the possibility of applying lubrication theory to the selection of optimum clearance fits for plain hydrodynamically lubricated bearings

BS1916 limits and fits for engineering is based on ISA bulletin 25 which was first issued in 1921 and designed for use with the metric system. It provides a wide range of tolerances for holes and shafts from which it is possible by suitable selection to satisfy a wide range of engineering requirements. The basic principle underlying the system is the allocation of letters to signify the magnitude of the displacement of that part of the tolerance zone which is nearest to the basic size and a number to indicate the magnitude of the tolerance. Capital letters are used for holes, small letters for shafts. The numbers referred to as fundamental tolerances are common to holes and shafts. In applying the system to inch sizes care was taken to ensure that fit combinations (H6/k4) would provide the same type of fit in the inch system as was established in the metric system throughout the whole of the Size range. It was also recommended that a unilateral hole basis be adopted in which the hole is the standard member and the tolerance specified as a value from nominal to plus an amount determined.by the number signifying the magnitude of the tolerance. Different types of fit are obtained by selecting from the standard shafts available the one whose fundamental deviation from basic size is considered to be the most suitable and :allocating to it a suitable standard tolerance When ISA bulletin 25 was issued great care was taken in selecting the disposition of the sizes allocated to standard shafts so that when one standard shaft was used with one standard hole it would provide a fit which -mould be functionally similar throughout the complete range of sizes. The decision of I.S.O. and B.S.I. to extend the size range from 20 inches to 200 inches caused reasonable doubts to exist about the reliability of this simple rule that one fit combination would be functionally similar throughout the whole of the extended size range. As this problem was examined in more detail cases were found where the above rule was not satisfactory over the extended or the smaller size range covered by the original standard (0.040” to 20”). In considering the possibility of applying theoretical analysis to this problem it was clear that the most difficult section was that concerned with the selection of clearance fits for hydrodynamically lubricated plain 'beatings. The present paper is a preliminary survey into this problem and the detailed analysis is restricted to the application of lubrication theory to the selection of what appear to be optimum clearance fits for hydrodynamically lubricated bearings and the means that may be used for comparing these results with the recommendations of I.S.A. bulletin 25 and BS1916. Figure 1 is a simplified representation of a plain bearing operating under conditions of hydrodynamic lubrication

Cranfield high precision universal measuring machine

The extensive programne of research undertaken by the Department of Production and Industrial .1.0.ministration at the College of Aeronautics, Cranfield into Metrology and Precision Engineering has shown the need for a Very High Precision, Very Universal Measuring Machine. Discussions with other organisations working on complex: problems in 2.ngineering Dimensional Metrology have confirmed this view. In particular, very valuable suggestions Have been made by senior officers from N. P.L. , R.A.E. Farnborough, Inspectorate of Ministry of National Defence and Inspection Panel of the Gas Turbine Co-ordinating Committee