Temperature and heat flux measurement techniques for aeroengine fire test: a review

This review is made of studies whereby some types of fire test measuring instrument were compared based on their mode of operation, sensing ability, temperature resistance and their calibration mode used for aero-engine applications. The study discusses issues affecting temperature and heat flux measurement, methods of measurement, calibration and uncertainties that occur in the fire test. It is found that the temperature and heat flux measurements of the flame from the standard burner need to be corrected and taken into account for radiation heat loss. Methods for temperature and heat flux measurements, as well as uncertainties analysis, were also discussed

Variation in gas chromatography (GC) analysis in setting up laboratory protocols for waste to energy novel fixed bed reactor setups

Gas Chromatography coupled with Mass Spectrometry (GC/MS) has been applied in various analytical chemistry works. However, to fine tune a system that can serve the purposes of pyrolysis oil identification has proven to be a laborious effort, especially when considering the fact that no standard protocol exists for such analysis. In addition, obtained products were yielded from a newly commissioned unit with a unique and novel design. In this study, a US patent office claimed reactor [SULTAN-1, Pyrolysis Reactor System for the Conversion and Analysis of Organic Solid Waste, Patent application number: 15,487,351] that degrades polyolefinc virgin and waste materials to obtain petroleum refinery and petrochemical feedstock, has been commissioned. The reactor produces three distinct physical states of matter products accumulated as testing specimens, i.e. solids, gaseous and oil. The samples analysed in this work were of the gas and oil produced by pyrolysis of end of life tyre (ELTs) shavings that required to have a special recipe to work with in the laboratory. Various MS cords were utilised and experimental setups to fine tune the process, and special emphasis was given on the gas samples variation in this communication. To reach the desired analysis results with high repeatability, a plethora of experiences of lab personnel and laboratory-based experimental work was accumulated. Laboratory protocols were also setup for this work. These will be detailed along the process execution which yielded a standard laboratory best practice analytical method as part of the State of Kuwait newly initiated Government Initiative project

Selection of Natural Fiber for Hybrid Kevlar/Natural Fiber Reinforced Polymer Composites for Personal Body Armor by Using Analytical Hierarchy Process

Kevlar 29 is the most widely used synthetic fiber for body armor applications and they have been derived from petroleum based resources. Depletion of petroleum resources and the increase in awareness about the eco-friendly materials encouraged the researchers to explore the potential use of natural fiber as an alternative for synthetic fibers. Hybridization of natural fiber with synthetic fiber will result in unique properties which is difficult to obtain from the individual fibers. In this research Analytical Hierarchy Process (AHP) was used to identify the most suitable natural fiber to be hybridized with Kevlar 29 fiber as a reinforcement in the polymer composites for personal body armor. Fourteen natural fibers and seven criteria's were selected and analyzed for hybridization with respect to the personal body armors design specification. Cocos nucifera sheath which is a naturally woven fiber yields the highest priority vector and it was selected as a most promising natural fiber for hybridization with Kevlar 29 for personal body armor. Eventually, sensitivity analysis was carried out to check the stability of the priority ranking

Mechanical properties of kenaf fibre thermoplastic polyurethane-natural rubber composites

Thermoplastic polyurethane-natural rubber TPUR-NR composites filled with treated and untreated kenaf fiber as filler were prepared at different TPUR and NR contents. The content of kenaf fiber was maintained at 12.5 wt % and the fiber was treated with 6 % solution of sodium hydroxide (NaOH), then dried for 24 hours in 100 °C, hot blended with polymer components, pulverized and pressed. The mechanical properties of the composites such as tensile, flexural and impact strength were determined, and their dependence on NaOH treatment of kenaf fibers was investigated. The analysis using scanning electron microscope (SEM) was implemented to identify the effect of alkali treatment on the microstructure of kenaf fiber and TPUR-NR composites. An improvement of fiber surface roughness and bonding between the fiber and polymer as well as an increase in impact energy and elongation at break of the composites was observed

Structural health monitoring (SHM) for composite structure undergoing tensile and thermal testing

Application of ultrasonic guided waves generated by piezoelectric smart transducers has become one of the widely-used techniques in structural health monitoring. This technique has led to significant improvements and profound effects in the field of aircraft reliability and safety. Lamb wave propagation on composite plate-like structure undergoing mechanical testing is investigated in the paper. Smart PZT actuator/sensor is bonded on the carbon-fiber and glassfiber epoxy composites, which are subjected to tensile and thermal stress tests. The acquired results indicate the changes in scattering waves in composites materials due to the applied thermal and tensile force. Wavelet analysis was incorporated in this research work in order to distinguish different structural status

The influence of equi-biaxially fabric prestressing on the flexural performance of woven e-glass/polyester reinforced composites

The flexural properties of plain-weave woven fabric-reinforced composites have been investigated to clarify the effects of equi-biaxially fabric prestressing on flexural characteristics. The prestressed composite samples were manufactured by applying the symmetrical tension load to both warp and weft yarns prior to matrix curing. The fabricated samples were tested under different fabric orientation angles, i.e. from warp to bias direction. The decline in the flexural properties of the prestressed composite due to matrix creep was checked. From three-point bending tests, the prestressed samples exhibited a maximum increase in the flexural performance, such as the strength and modulus, of ∼16% at a prestressing level of 50 MPa when compared with unprestressed counterparts. The level of improvement in the flexural properties reduced with increasing fabric orientation angle. The creep was induced in the prestressed matrix and subsequent decline in the improved flexural properties was indicated in the prestressed samples. The decline in flexural properties occurred mostly during the short-term creep

The vertical cloud structure of the West African monsoon: a 4 year climatology using CloudSat and CALIPSO

The West African summer monsoon (WAM) is an important driver of the global climate and locally provides most of the annual rainfall. A solid climatological knowledge of the complex vertical cloud structure is invaluable to forecasters and modelers to improve the understanding of the WAM. In this paper, 4 years of data from the CloudSat profiling radar and CALIPSO are used to create a composite zonal mean vertical cloud and precipitation structure for the WAM. For the first time, the near-coincident vertical radar and lidar profiles allow for the identification of individual cloud types from optically thin cirrus and shallow cumulus to congestus and deep convection. A clear diurnal signal in zonal mean cloud structure is observed for the WAM, with deep convective activity enhanced at night producing extensive anvil and cirrus, while daytime observations show more shallow cloud and congestus. A layer of altocumulus is frequently observed over the Sahara at night and day, extending southward to the coastline, and the majority of this cloud is shown to contain supercooled liquid in the top. The occurrence of deep convective systems and congestus in relation to the position of the African easterly jet is studied, but only the daytime cumulonimbus distribution indicates some influence of the jet position

Effect of kenaf fibres on trauma penetration depth and ballistic impact resistance for laminated composites

Combat helmets have been utilized to provide protection against a variety of ballistic threats, by reducing traumatic head injuries and fatalities. Nevertheless, head protection from injury is critical to function and for survivability. Soldiers and civilians incur Traumatic Brain Injury (TBI) most commonly from exposure to homemade bombs or improvised explosive devices. Although the Personal Armor System for Ground Troops (PASGT) helmet is expensive, environmental issues are some technical advantages that encourage using natural/synthetic hybrid laminated composites. The effects of different configuration patterns of kenaf fibers on the Backface Signature and energy absorbed by a military helmet (PASGT) were investigated. The ballistic behaviors of the 19 layers of aramid composite and plain woven kenaf composite were compared to hybrid laminated composites. The ballistic impact tests were performed using a 9 mm full metal jacket bullet and fragment simulating projectiles at various impact velocities, using a powder gun on fabricated square panels and helmets. The results showed the positive effect of hybridization in terms of energy absorbed (i.e. penetration), Backface Signature and damage mechanisms for ballistic impact and NIJ (National Institute of Justice) tests. Hybridization of plain woven kenaf/Kevlar laminated composites will open new avenues to reduce the dependency on the ballistic resistance component (Kevlar) in the helmet shell

Management of obstetric anal sphincter injury: a systematic review & national practice survey

BACKGROUND: We aim to establish the evidence base for the recognition and management of obstetric anal sphincter injury (OASI) and to compare this with current practice amongst UK obstetricians and coloproctologists. METHODS: A systematic review of the literature and a postal questionnaire survey of consultant obstetricians, trainee obstetricians and consultant coloproctologists was carried out. RESULTS: We found a wide variation in experience of repairing acute anal sphincter injury. The group with largest experience were consultant obstetricians (46.5% undertaking ≥ 5 repairs/year), whilst only 10% of responding colorectal surgeons had similar levels of experience (p < 0.001). There was extensive misunderstanding in terms of the definition of obstetric anal sphincter injuries. Overall, trainees had a greater knowledge of the correct classification (p < 0.01). Observational studies suggest that a new 'overlap' repair using PDS sutures with antibiotic cover gives better functional results. However, our literature search found only one randomised controlled trial (RCT) on the technique of repair of OASI, which showed no difference in incidence of anal incontinence at three months. Despite this, there was a wide variation in practice, with 337(50%) consultants, 82 (55%) trainees and 80 (89%) coloproctologists already using the 'overlap' method for repair of a torn EAS (p < 0.001). Although over 50% of colorectal surgeons would undertake long-term follow-up of their patients, this was the practice of less than 10% of obstetricians (p < 0.001). Whilst over 70% of coloproctologists would recommend an elective caesarean section in a subsequent pregnancy, only 22% of obstetric consultants and 14% of trainees (p < 0.001). CONCLUSION: An agreed classification of OASI, development of national guidelines, formalised training, multidisciplinary management and further definitive research is strongly recommended

Mechanical tuning of the evaporation rate of liquid on crossed fibers

We investigate experimentally the drying of a small volume of perfectly wetting liquid on two crossed fibers. We characterize the drying dynamics for the three liquid morphologies that are encountered in this geometry: drop, column and a mixed morphology, in which a drop and a column coexist. For each morphology, we rationalize our findings with theoretical models that capture the drying kinetics. We find that the evaporation rate depends significantly on the liquid morphology and that the drying of liquid column is faster than the evaporation of the drop and the mixed morphology for a given liquid volume. Finally, we illustrate that shearing a network of fibers reduces the angle between them, changes the morphology towards the column state, and so enhances the drying rate of a volatile liquid deposited on it