The effect of temperature changes on to quasi-static tensile and flexural performance of glass fibre reinforced PA66 composites

A significant method of reducing CO2 emissions in road vehicles is to reduce the vehicle mass. One means in which this can be achieved is to adopt lightweight materials such as thermoplastic composites. Thermoplastics offer advantages in term of weight when compared to conventional steel and aluminium casting. In this study thermal mechanical testing has been conducted on two types of commercial polyamide 66 (PA66) with 35 wt.% short glass fibre reinforcement. One of the materials was impact modified with an elastomer to increase material toughness. Experimental results showed both the reinforced PA66 materials to be temperature dependent. All test results demonstrated the trade-off in the mechanical properties of the two materials especially the impact modified. PA66 with 35 wt.% short glass fibre exhibits the best tensile strength, flexural strength and modulus for each temperature tested. Whereas the impact modified PA66 with 35 wt.% short glass fibre exhibits the higher strain and toughness for each temperature tested

Nanoparticle reinforced polyamide 66 glass fibre composites for automotive under-the-bonnet-applications.

This work focus on an engine oil pan application which expects component materials operate at elevated temperatures due to returning oil heating up during operation. Mechanical properties of thermoplastic composites are known to be temperature dependent with performance losses elevated temperatures. A pilot study was conducted to benchmark the current state-of-the-art glass reinforced polyamide materials at elevated temperatures to address a gap in this knowledge. Experiments included tensile, 3-point flexural, and gas gun impact where conducted at elevated temperatures 23°C, 65°C, 90°C and 120°C. Experimental results demonstrated the trade-off in the mechanical properties of the two materials especially when one of the materials had been impact modified with an elastomer (PA66-GF-E). PA66-GF-E mechanical and impact performance can be considered fit of purpose as a suitable material for an oil pan application but is more expensive. As an extra compounding step is required to graft the elastomer to the PA66 matrix. Literature studies into replacements for the elastomer suggested nanoparticles as they can be compounded at the same time as the GF and in turn eliminate secondary compounding costs. Six 3-phase nanocomposite where then compounded using a twin screw extruder. Additions of OMMT and SiO2where done in 2, 3 and 4wt.% for each nanocomposite. Testing of the 3-phase nanocomposites indicated the GF reduction has reduced mechanical strength in all results, but still demonstrates each nanomaterial and volume has been successful. Thermomechanical testing and aging suggests an optimised SiO2 in wt.% of 2 or 3 could replace an elastomer as an impact modifier. OMMT grades did not have a significant improvement to over the SiO2 grades to consider suitable for the oil pan application. However this work does builds a strong case for further work to continue developing 3-phase nanocomposites by improving the compounding setup.PhD in Transport System

Productive uses of domestic water: opportunity or threat?

This paper argues that small-scale productive uses of water such as for garden irrigation, keeping livestock, post-harvest crop processing and other micro-enterprises should receive better consideration in the planning of domestic water supply systems. Currently opportunities are being lost to maximize the impacts on poverty alleviation of improvements in water supply, and sustainability is undermined by failing to address the productive needs of users. An agenda for possible policy change, implementation actions and further research is included based upon the outcomes of an earlier international symposium

Evaluation of key geometrical and mechanical properties for remote laser welded AC-170PX aluminium joints

Use of lightweight materials to produce automotive body structures is one of the key trends adopted by automotive manufacturers to minimise emission of greenhouse gases, and subsequently, reduction of fuel consumption. Aluminium alloys are one of the promising lightweight materials which are increasingly used for automotive body-in-white structures. Such applications demand both efficient and effective joining/welding methods to produce repeatable, durable and strong joints without significant alteration of material properties. Remote laser welding (RLW) is an emerging joining technology and increasingly being used to produce lightweight joints as it satisfies the demand for high production throughput at low cost. This paper investigates the effects of process parameters when seam tracking remote laser welding is used to create an autogenous fillet edge weld of automotive grade aluminum alloy (AC-170PX) in lap configuration without shielding gas. The effects of laser power and welding speed on the key geometric features are reported together with details of the weld microstructure. Joint strength is evaluated by performing a lap shear test. It is found that the laser power and welding speed have dominant influence on key geometric features and subsequently on the lap shear strength. Relatively larger grain size in the fusion zone reduces the microhardness by up to 20% in comparison with the base material

Psychomotor Impairment Detection via Finger Interactions with a Computer Keyboard During Natural Typing

Modern digital devices and appliances are capable of monitoring the timing of button presses, or finger interactions in general, with a sub-millisecond accuracy. However, the massive amount of high resolution temporal information that these devices could collect is currently being discarded. Multiple studies have shown that the act of pressing a button triggers well defined brain areas which are known to be affected by motor-compromised conditions. In this study, we demonstrate that the daily interaction with a computer keyboard can be employed as means to observe and potentially quantify psychomotor impairment. We induced a psychomotor impairment via a sleep inertia paradigm in 14 healthy subjects, which is detected by our classifier with an Area Under the ROC Curve (AUC) of 0.93/0.91. The detection relies on novel features derived from key-hold times acquired on standard computer keyboards during an uncontrolled typing task. These features correlate with the progression to psychomotor impairment (p < 0.001) regardless of the content and language of the text typed, and perform consistently with different keyboards. The ability to acquire longitudinal measurements of subtle motor changes from a digital device without altering its functionality may allow for early screening and follow-up of motor-compromised neurodegenerative conditions, psychological disorders or intoxication at a negligible cost in the general population.Comunidad de Madri

The initiation and evolution of the River Nile

This work was funded by a NERC Open CASE PhD studentship award NE/I018433/1, the NERC Isotope Geoscience Facilities Steering Committee (IP-1248-0511, IP-1299-0512), and BP Egypt who we also thank for provision of samples and assistance in Egypt. We thank C. Stewart, V. Pashley and N. Roberts at NIGL for valuable laboratory assistance. This paper benefited from careful reviews by D. Chew and an anonymous reviewer.Peer reviewedPublisher PD

Квазиклассическое описание излучения электрона в графене

Supplementary Item 12: Tracer isotope data

Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae

We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of superhump period are found to be composed of three distinct stages: early evolutionary stage with a longer superhump period, middle stage with systematically varying periods, final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods less than 0.08 d show positive period derivatives. Contrary to the earlier claim, we found no clear evidence for variation of period derivatives between superoutburst of the same object. We present an interpretation that the lengthening of the superhump period is a result of outward propagation of the eccentricity wave and is limited by the radius near the tidal truncation. We interpret that late stage superhumps are rejuvenized excitation of 3:1 resonance when the superhumps in the outer disk is effectively quenched. Many of WZ Sge-type dwarf novae showed long-enduring superhumps during the post-superoutburst stage having periods longer than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently, mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives and are excellent candidate for the systems around or after the period minimum of evolution of cataclysmic variables (abridged).Comment: 239 pages, 225 figures, PASJ accepte