Investigation in optimisation of accuracy with non-contact systems by influencing variable processes

The use of 3D scanning systems is becoming increasingly popular and an essential tool for manufacturers for inspection and measurement. With such systems being utilised on the manufacturing shop floor due to their portability and ease of use, it is no doubt that such systems are designed to address a variety of users whom, with minimal training can operate the equipment. Due to continuing demands of high-quality products there is the need for manufacturers of 3D scanning systems to develop technologies that deliver fast and accurate information. However, one of the key challenges lies not in the training of people to use the equipment, but to develop engineers who can produce traceable, accurate and precise results with a declared statement of confidence quantifying the quality of the measurement. This statement of the quality of the output results relies on employing a set of workflow actions that involve planning, capture, processing and analysis, and finally output. This paper sets out to show how the results from a set of workflow actions from different categories of 3D scanning devices affects the quality of output

Laterally unrestrained bearing strength of hot-wet conditioned pultruded FRP material

Presented in this paper are test results of a study pertaining to the reduction in bearing strength due to the effect of hot-wet conditioning on specimens cut from a polyester matrix based pultruded FRP structural shape. A total of 100 coupons (for 20 batches of five) were immersed in distilled water for three and six months at a constant temperature of 40°C. Subsequently, they were load tested using stainless steel ‘pins’ of M10 and M20 sizes with material orientations of 0o, 45o and 90o to the direction of pultrusion. Furthermore, this test series considered the effect of loading with and without bolt thread in the bearing zone. Testing employed a non-standard set-up that accommodates smaller test coupons, allowing material to be sourced from the web and flange of a 254×254×9.53 mm wide flange shape. An evaluation of the salient results provides characteristic bearing strength values (in accordance with Annex D of EN1990) and comparisons are drawn between equivalent strengths for non-aged (zero months) material from a previous test series. The degree of strength reduction is found to be influenced by both the ‘pin’ size and type, and observations are drawn towards the safe and reliable design of bolted connections

Long-term follow up of intractable chronic short lasting unilateral neuralgiform headache disorders treated with occipital nerve stimulation

BACKGROUND: Occipital nerve stimulation is a potential treatment option for medically intractable short-lasting unilateral neuralgiform headache attacks. We present long-term outcomes in 31 patients with short-lasting unilateral neuralgiform headache attacks treated with occipital nerve stimulation in an uncontrolled open-label prospective study. METHODS: Thirty-one patients with intractable short-lasting unilateral neuralgiform headache attacks were treated with bilateral occipital nerve stimulation from 2007 to 2015. Data on attack characteristics, quality of life, disability and adverse events were collected. Primary endpoint was change in mean daily attack frequency at final follow-up. RESULTS: At a mean follow-up of 44.9 months (range 13-89) there was a 69% improvement in attack frequency with a response rate (defined as at least a 50% improvement in daily attack frequency) of 77%. Attack severity reduced by 4.7 points on the verbal rating scale and attack duration by a mean of 64%. Improvements were seen in headache-related disability and depression. Adverse event rates were favorable, with no electrode migration or erosion reported. CONCLUSION: Occipital nerve stimulation appears to offer a safe and efficacious treatment for refractory short-lasting unilateral neuralgiform headache attacks with significant improvements sustained in the long term. The procedure has a low adverse event rate when conducted in highly specialised units

OnabotulinumtoxinA for hemicrania continua: open label experience in 9 patients

BACKGROUND: Hemicrania continua is a strictly unilateral, continuous headache, typically mild to moderate in severity, with severe exacerbations commonly accompanied by cranial autonomic features and migrainous symptoms. It is exquisitely responsive to Indomethacin. However, some patients cannot tolerate treatment, often due to gastrointestinal side effects. Therapeutic alternatives are limited and controlled evidence lacking. METHODS: We present our experience of nine patients treated with OnabotulinumtoxinA for hemicrania continua. All patients were injected using the PREEMPT (Phase 3 REsearch Evaluating Migraine Prophylaxis Therapy) protocol for migraine. RESULTS: Five of nine patients demonstrated a 50% or more reduction in moderate to severe headache days with OnabotulinumtoxinA with a median reduction in moderate to severe headache days of 80%. Patient estimate of response was 80% or more in five subjects. The median and mean duration of response in the five responders was 11 and 12 weeks (range 6-20 weeks). Improvements were also seen in headache-associated disability CONCLUSIONS: OnabotulinumtoxinA adds a potential option to the limited therapeutic alternatives available in hemicrania continua

Microvascular decompression or neuromodulation in patients with SUNCT and trigeminal neurovascular conflict?

Objectives To assess the effectiveness of neuromodulation and trigeminal microvascular decompression (MVD) in patients with medically-intractable short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT). Methods Two patients with medically refractory SUNCT underwent MVD following beneficial but incomplete response to neuromodulation (occipital nerve stimulation and deep brain stimulation). MRI confirmed neurovascular conflict with the ipsilateral trigeminal nerve in both patients. Results Although neuromodulation provided significant benefit, it did not deliver complete relief from pain and management required numerous postoperative visits with adjustment of medication and stimulation parameters. Conversely, MVD was successful in eliminating symptoms of SUNCT in both patients with no need for further medical treatment or neuromodulation. Conclusion Neuromodulation requires expensive hardware and lifelong follow-up and maintenance. These case reports highlight that microvascular decompression may be preferable to neuromodulation in the subset of SUNCT patients with ipsilateral neurovascular conflict

Treatment of intractable hemicrania continua by occipital nerve stimulation

Hemicrania continua (HC) is characterised by a strictly unilateral continuous headache with ipsilateral autonomic features and migrainous symptoms that is exquisitely sensitive to indomethacin.1 As more than 30% of patients report side effects with indomethacin, there is need for an effective and safe alternative. Although several drugs have been used in open-label studies, none offer the same magnitude of response. Occipital nerve stimulation (ONS) has been performed in headache conditions such as chronic migraine and chronic cluster headache, both conditions with clinical similarities to HC and appears to be a safe, potentially efficacious treatment even in those failing all available medical treatments.2 We report the long-term follow-up of a new cohort of 16 patients with HC treated with ONS

Ventral tegmental area deep brain stimulation in refractory short-lasting unilateral neuralgiform headache attacks

Short-lasting unilateral neuralgiform headache attacks are primary headache disorders characterized by short-lasting attacks of unilateral pain accompanied by autonomic features. A small minority are refractory to medical treatment. Neuroimaging studies have suggested a role of the posterior hypothalamic region in their pathogenesis. Previous case reports on deep brain stimulation of this region, now understood to be the ventral tegmental area, for this disorder are limited to a total of three patients. We present a case series of 11 new patients treated with ventral tegmental area deep brain stimulation in an uncontrolled, open-label prospective observational study. Eleven patients with refractory short-lasting unilateral neuralgiform headache attacks underwent ipsilateral ventral tegmental area deep brain stimulation in a specialist unit. All patients had failed, or been denied access to, occipital nerve stimulation within the UK’s National Health Service. Primary endpoint was change in mean daily attack frequency at final follow-up. Secondary outcomes included attack severity, attack duration, headache load (a composite score of attack frequency, severity and duration), quality of life measures, disability and affective scores. Information was also collected on adverse events. Eleven patients (six male) with a median age of 50 years (range 26–67) were implanted between 2009 and 2014. Median follow-up was 29 months (range 7–63). At final follow-up the median improvement in daily attack frequency was 78% (interquartile range 33%). Response rate (defined as at least a 50% improvement in daily attack frequency) was 82% and four patients were rendered pain-free for prolonged periods of time. Headache load improved by 99% (interquartile range 52%). Improvements were observed in a number of quality of life, disability and affect measures. Adverse events included mild incision site pain, subcutaneous displacement of the implantable pulse generator, transient oscillopsia and minor wound infection. One patient required removal of the system due to wound infection. Ventral tegmental area deep brain stimulation may be an effective treatment option for refractory short-lasting unilateral neuralgiform headache attack patients who have failed other therapies

The Hy-MASS concept : Hydrothermal microwave assisted selective scissoring of cellulose for: In situ production of (meso)porous nanocellulose fibrils and crystals

The hydrothermal microwave-assisted selective scissoring (Hy-MASS) of depectinated orange peel residues (OPR), produced via conventional acid hydrolysis and acid-free microwave processing, to yield (meso)porous nanocellulose fibrils and crystals simultaneously in the absence of additional auxiliary reagents and/or mechanical treatment is reported. In the stepwise microwave hydrothermal treatment (MHT) of OPR from 120 °C-200 °C at 20 °C intervals, release of residual pectins and hemicelluloses is observed up to 180 °C producing nanocellulose fibrils (3-15 × 500-2000 nm). Beyond 180 °C, selective leaching/hydrolysis of amorphous regions occur to yield nanocellulose crystals (200-400 × 40-50 nm) and crystallites (5-15 × 40-50 nm). This selective, step-wise scissoring process is termed Hy-MASS Concept. Structure, morphology and properties of (meso)porous nanocellulose are strongly influenced by pectin extraction methodology employed. With acid depectinated OPR, deconstruction of the lignocellulosic matrix via microwave is hastened by approx. 20 °C with respect to acid-free microwave depectinated OPR. Td of acid depectinated nanocelluloses (CMC) is ca. 350 °C compared to microwave depectinated nanocelluloses (MMC, Td, varies 342-361 °C). Nanocellulose produced via microwave pre-treatment is (meso)porous: BJH pore size 5-35 nm; BET surface area, 1.5-107 m2 g-1, and; BJH pore volume, 0.01-0.27 cm3 g-1, when compared to acid pre-treated counterparts. The crystallinity index of CMC and MMC increases in two stages, 120-140 °C (ca. 8%) and at 180-200 °C (5-9%). XRD revealed presence of calciuim salts, most likely calcium oxalate. The hydration capacities of nanocelluloses (12-23 g water per g sample) are much higher than their precursors or literature citrus nanocellulose

Acid-free microwave-assisted hydrothermal extraction of pectin and porous cellulose from mango peel waste-towards a zero waste mango biorefinery : Towards a Zero Waste Mango Biorefinery

Mango is the second most consumed tropical fruit after banana and the by-products of mango processing (peel, kernel and seed) roughly comprise 35-60% of the total fruit weight, thus representing a potentially high volume resource of exploitable biobased chemicals and materials. Herein, conversion and characterisation of waste mango peels from three different cultivars (Alphonso, Honey and Tommy Atkins) into pectin and porous cellulose using low temperature microwave-assisted acid-free hydrolytic conditions is reported. Microwave-assisted acid-free extraction yielded up to 11.63% (dry weight basis) of pectin which was characterised by IR, NMR (both solution and solid phase) and TGA which showed close similarity to commercial (acid extracted) pectin. The degree of esterification of pectin was determined by 13C NMR (75.6-86.2%) and titrimetry (79.3-87.7%) and the pectin showed excellent gelling ability. The molecular weight as determined by GPC was in the range 14130 (Honey)-25540 (Tommy Atkins). Porosity measurements on the depectinated residue, i.e., residual cellulosic matter showed mesoporous characteristics: average pore diameter, 9.3 nm (Alphonso)-10.5 nm (Honey), however with poor surface area 16.3 m2 g-1 (Honey)-26.0 m2 g-1. Interestingly, a second microwave hydrothermal treatment on these residues retained mesoporosity whilst significantly increasing surface area (88.8 m2 g-1 (Honey)-124.0 m2 g-1 (Alphonso)) and pore volume by approximately six-fold. This is the first detailed combined study of microwave-assisted extraction to yield pectin and mesoporous cellulose towards a potential zero waste mango biorefinery

Evolution of Surface Nanopores in Pressurised Gyrospun Polymeric Microfibers

The selection of a solvent or solvent system and the ensuing polymer–solvent interactions are crucial factors affecting the preparation of fibers with multiple morphologies. A range of poly(methylmethacrylate) fibers were prepared by pressurised gyration using acetone, chloroform, N,N-dimethylformamide (DMF), ethyl acetate and dichloromethane as solvents. It was found that microscale fibers with surface nanopores were formed when using chloroform, ethyl acetate and dichloromethane and poreless fibers were formed when using acetone and DMF as the solvent. These observations are explained on the basis of the physical properties of the solvents and mechanisms of pore formation. The formation of porous fibers is caused by many solvent properties such as volatility, solubility parameters, vapour pressure and surface tension. Cross-sectional images show that the nanopores are only on the surface of the fibers and they were not inter-connected. Further, the results show that fibers with desired nanopores (40–400 nm) can be prepared by carefully selecting the solvent and applied pressure in the gyration process