1,699 research outputs found

    A study of the effect of palm oil as MQL lubricant on high speed drilling of titanium alloys

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    The main objective was to study the potency of MQL palm oil (MQLPO) as a lubricant in the high speed drilling of Ti–6Al–4V. For the comparison, MQL synthetic ester (MQLSE), air blow and flood conditions were selected. Uniform flank wear, micro-chipping, thermal cracking and flaking were the dominant tool failure modes. It was found that MQLSE and MQLPO gave comparable performance with the flood conditions. In addition, MQLPO outperformed MQLSE on the cutting forces, temperature, power and specific cutting energy. This shows that palm oil can be used as a viable alternative to synthetic ester for MQL lubricant

    Study of sumac extract (Rhus coriaria L.), lactic acid and thyme oil as decontaminants for shelf life extension of refrigerated rabbit meat

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    In an attempt to improve the microbiological quality and extend the shelf-life of refrigerated rabbit meat, four groups of rabbit meat from New Zealand breed were prepared, the 1st group was untreated (control), while the other three groups were treated with lactic acid 0.5 %, thyme oil 0.5 % and water extract of sumac 8 % by dipping for 1, 1 and 10 min, respectively. Then the samples were refrigerated at 2 ± 1 °C to be periodically examined for their sensory and microbiological status. The control and treated samples showed excellent overall acceptability by panellists at zero-day of examination, off odours and tastes were noticed by the day 9, 12, 9 and 15 day of storage in control (C), lactic acid (LA), thyme oil (TO) and water extract of sumac (WES) treated groups, respectively. There was no significant differences in aerobic plate counts “APC” (at p < 0.05) between treated and untreated groups at zero and 3rd day of examination, while at 6th and 9th day of refrigerated storage, the values of APC were significantly lower in LA and WES treated groups than C and TO treated groups. The APC results confirm the concept that the slowest growth rate of the total bacterial population extends the shelf life of rabbit meat. Approximately, similar pattern to that of APC was observed in the results of coliforms (MPN). The MPN values of faecal coliforms and E. coli were relatively low, which could be attributed to the preparation of rabbit samples under strict hygienic measures. The obtained results in the present study suggest that WES can be used as a decontaminant for rabbit and poultry meat at each decontamination step instead of other chemical substances which could affect the acceptability of the final product and remain some hazardous residues. Keywords: sumac, rabbit, quality, shelf life, thyme oil, lactic acid

    New possibilities for neuroprotection in neonatal hypoxic-ischemic encephalopathy

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    Around 0.75 million babies worldwide suffer from moderate or severe hypoxic-ischemic encephalopathy (HIE) each year resulting in around 400,000 babies with neurodevelopmental impairment. In 2010, neonatal HIE was associated with 2.4% of the total Global Burden of Disease. Therapeutic hypothermia (TH), a treatment that is now standard of care in high-income countries, provides proof of concept that strategies that aim to improve neurodevelopment are not only possible but can also be implemented to clinical practice. While TH is beneficial, neonates with moderate or severe HIE treated with TH still experience devastating complications: 48% (range: 44–53) combined death or moderate/severe disability. There is a concern that TH may not be effective in low- and middle-income countries. Therapies that further improve outcomes are desperately needed, and in high-income countries, they must be tested in conjunction with TH. We have in this review focussed on pharmacological treatment options (e.g. erythropoietin, allopurinol, melatonin, cannabidiol, exendin-4/exenatide). Erythropoietin and allopurinol show promise and are progressing towards the clinic with ongoing definitive phase 3 randomised placebo-controlled trials. However, there remain global challenges for the next decade. Conclusion: There is a need for more optimal animal models, greater industry support/sponsorship, increased use of juvenile toxicology, dose-ranging studies with pharmacokinetic-pharmacodynamic modelling, and well-designed clinical trials to avoid exposure to harmful medications or abandoning putative treatments

    Investigation of tool wear and surface integrity on MQL machining of Ti-6AL-4V using biodegradable oil

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    Minimum quantity lubrication (MQL) machining involves the application of small quantity of lubricant to the tool–workpiece interface. This paper describes the results of an investigation on the effects of using different MQL lubricants (synthetic ester and palm oil) on the drilling of Ti-6Al-4V. Dry cutting was also performed for comparison purposes. It was found that drilling under dry conditions resulted in the shortest tool life due to severe chipping. MQL is beneficial to the measured responses such as tool life, thrust force, torque, and temperature. The outstanding performance of palm oil in reducing the value of those responses was attributed to its ability to form a thin film which promoted boundary lubrication during the machining process. The presented results indicated the substantial benefit of using palm oil in terms of microhardness, surface roughness, and subsurface deformation. This work shows that palm oil can be used as a viable alternative to a synthetic ester as a MQL lubricant

    Neuroprotective Effects of Diabetes Drugs for the Treatment of Neonatal Hypoxia-Ischemia Encephalopathy

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    The perinatal period represents a time of great vulnerability for the developing brain. A variety of injuries can result in death or devastating injury causing profound neurocognitive deficits. Hypoxic-ischemic neonatal encephalopathy (HIE) remains the leading cause of brain injury in term infants during the perinatal period with limited options available to aid in recovery. It can result in long-term devastating consequences with neurologic complications varying from mild behavioral deficits to severe seizure, intellectual disability, and/or cerebral palsy in the newborn. Despite medical advances, the only viable option is therapeutic hypothermia which is classified as the gold standard but is not used, or may not be as effective in preterm cases, infection-associated cases or low resource settings. Therefore, alternatives or adjunct therapies are urgently needed. Ongoing research continues to advance our understanding of the mechanisms contributing to perinatal brain injury and identify new targets and treatments. Drugs used for the treatment of patients with type 2 diabetes mellitus (T2DM) have demonstrated neuroprotective properties and therapeutic efficacy from neurological sequelae following HIE insults in preclinical models, both alone, or in combination with induced hypothermia. In this short review, we have focused on recent findings on the use of diabetes drugs that provide a neuroprotective effect using in vitro and in vivo models of HIE that could be considered for clinical translation as a promising treatment

    Mutual Coupling Reduction in Antenna Using EBG on Double Substrate

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    In this paper, a mutual coupling studies is conducted between two-element array antenna on dual substrate. A single patch antenna is firstly designed on dual substrate layer to testify appropriate performance at 2.45 GHz. Subsequently, an array of two element patches on dual substrate are constructed with one of them is incorporated with three EBG unit cell on the bottom substrate. The radiating patch is on the top substrate, while the EBG unit cells is on the bottom substrate. With EBGs in separate layers from the antenna array, the antenna elements are closely separated by a distance of 22 mm with a significant reduced mutual coupling of -26.61 dB. This correspond to a distance reduction of 34.68%. The proposed structure implemented only three EBG unit cells. Apart from that, the study of overlapped case of EBG with the antenna is also presented

    An experimental investigation of cutting temperature and tool wear in 2 dimensional ultrasonic vibrations assisted micro-milling

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    © The Authors, published by EDP Sciences, 2017.Two dimensional Ultrasonic vibration assisted milling (2D UVAM) well knows process that involved in high tech system to generate ultra range of frequency applied to the milling process. More industries nowadays become aware taking this opportunity to improve their productivity without decreasing their product accuracies. This paper investigate a comparative machining between UVAM and conventional machining (CM) in tool wear and cutting temperature in milling process. Micro amplitude and sine wave frequency will be generate into the workpiece jig by piezo-Actuator. Thus, creating a micro gap that allow heat remove effectively with the chip produces. A more complex tool trajectory mechanics of 2D UVAM has been found during this research. The approaching the tool tip into the workpiece surfaces is affected by the amplitude displacement along the frequency applied. It is found that the tool wear was reduce and surface roughness improvement by applying the 2D UVAM compared to the CM when choosing the optimum amplitude and appropriate frequency

    Hole making process of carbon fiber reinforced polymer (CFRP) using end mill cutting tool

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    This paper presents an alternative way of producing a hole by using a helical milling concept on a carbon fiber reinforced polymer (CFRP). Delamination is a major problem associated with making a hole by drilling on the CFRP. This study focused on helical milling technique using a vertical machining center in order to produce a hole. Various levels of cutting parameter such as cutting speed, feed rate and depth of cut have been chosen to observe the effect of trust force, delamination and surface roughness. The result will be used to determine on which cutting parameters give the best hole quality that will achieved by this new approached

    Experimental study of helical milling on CFRP (carbon fibre reinforced polymer) for the hole making process

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    Generate borehole by helical milling process may be used effectively since accurate location of the hole may be secured by means of the feed screw graduations. Fiber delamination which is the main defect occurred during hole making process on carbon fiber reinforced polymer (CFRP) were investigate throughout an experimental study. Effects of thrust force (Fz), delamination factor (Fd) and surface roughness are evaluated. Objective of the experiment are to find best cutting parameter and tool design suitable to performed helical milling operation on CFRP. Two types of end mill with 4 flutes were used and results are evaluated. It was found that tool design 2-1 has higher performance on CFRP

    Cost saving with ultrasonography in a developing country district hospital

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    Objective: To estimate the potential monetary reduction induced by the introduction of an ultrasound unit in a major district hospital in a developing country. Design: Propective study. Subjects: Patients referred with abnominal diseases and pregnancy. Setting: 'Wad Medani Teaching Hospital, Central Sudan. Results: Local specialists referring the patients stated that an estimated 792 radiologic procedures would have been carried out to obtain the same amount of information as achieved by ultrasound. Such procedures budgeted approximately 8100 US dollars, in terms of equipment, material and personnel by 1987 rates. Such savings have benefited all departments of the hospital. Conclusion: The authors consider this as evidence for the fact that despite its initial high investment (15000 US dollars), availability of ultrasound virtually reduced expenditure on other radiological diagnostic procedures. This is of special benefit for the limited budgets of hospitals in non-industrialiied countries.East African Medical Journal, May 1999, 272-27
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