Equivalent Modulus of Asphalt Concrete Layers

A flexible pavement structure usually comprises more than one asphalt layer, with varying thicknesses and properties, in order to carry the traffic smoothly and safely. It is easy to characterize each asphalt layer with different tests to give a full description of that layer; however, the performance of the whole; asphalt structure needs to be properly understood. Typically, pavement analysis is carried out using multi-layer linear elastic assumptions, via equations and computer programs such as KENPAVE, BISAR, etc. These types of analysis give the response parameters including stress, strain, and deflection at any point under the wheel load. This paper aims to estimate the equivalent Resilient Modulus (MR) of the asphalt concrete layers within a pavement structure by using their individual MR values. To achieve this aim, eight samples were cored from Iraqi Expressway no. 1; they had three layers of asphalt and were tested to obtain the MR of each core by using the uniaxial repeated loading test at 25 and 40 °C. The samples were then cut to separate each layer individually and tested for MR at the same testing temperatures; thus, a total of 60 resilient modulus tests were conducted. A new approach was introduced to estimate the equivalent MR as a function of the MR value for each layer. The results matched the values obtained by KENPAVE analysis

The Evolution of X-ray Bursts in the "Bursting Pulsar" GRO J1744-28

GRO J1744-28, commonly known as the `Bursting Pulsar', is a low mass X-ray binary containing a neutron star and an evolved giant star. This system, together with the Rapid Burster (MXB 1730-33), are the only two systems that display the so-called Type II X-ray bursts. These type of bursts, which last for 10s of seconds, are thought to be caused by viscous instabilities in the disk; however the Type II bursts seen in GRO J1744-28 are qualitatively very different from those seen in the archetypal Type II bursting source the Rapid Burster. To understand these differences and to create a framework for future study, we perform a study of all X-ray observations of all 3 known outbursts of the Bursting Pulsar which contained Type II bursts, including a population study of all Type II X-ray bursts seen by RXTE. We find that the bursts from this source are best described in four distinct phenomena or `classes' and that the characteristics of the bursts evolve in a predictable way. We compare our results with what is known for the Rapid Burster and put out results in the context of models that try to explain this phenomena.Comment: Accepted to MNRAS Aug 17 201

High purity FAU-type zeolite catalysts from shale rock for biodiesel production

FAU-type zeolite was prepared using Irish shale rock and tested as a catalyst in the liquid-phase esterification of oleic acid (a model test reaction for biodiesel production). A systematic study was conducted (over the stated preparation ranges) by varying the water:shale ratio (4:1–15:1 by mass), and mixing (1–24 h), aging (6–48 h) and hydrothermal treatment times (6–72 h) to determine the optimal parameters. XRD confirmed that the product purity was highly dependent on the experimental conditions used. The BET surface area of the calcined FAU-type zeolite was 571 m2 g−1 and its crystal purity was comparable to that of a commercial zeolite Y. The prepared zeolite was catalytically active in the esterification of oleic acid with ethanol reaching a maximum of 78% conversion after 90 mins, which is practically identical to that recorded for commercial zeolite Y

N′-[(E)-2-chlorobenzylidene]-2-(6-methoxynaphthalen-2-yl) propanohydrazide

In the title compound, C21H19ClN2O2, the benzene ring and the naphthalene ring system are oriented at a dihedral angle of 65.24 (10)°. In the crystal, N—H⋯O, C—H⋯N and C—H⋯O hydrogen bonds link the mol­ecules, forming chains along the b-axis direction. Further C—H⋯O hydrogen bonds link the chains, forming corrugated sheets lying parallel to (10-1)

A new polymorph of N-(2-{N′-[(1E)-2-hy­dr­oxy­benzyl­­idene]hydrazinecarbon­yl}phen­yl)benzamide

The title compound, C 21 H 17 N 3 O 3 , is a new polymorph of an already published structure [Shashidhar et al. (2006). Acta Cryst. E62, o4473-o4475]. The previously reported structure crystallizes in the monoclinic space group C2/c, whereas the structure reported here is in the tetragonal space group I4 1 /a. The bond lengths and angles are similar in both structures. The molecule adopts an extended conformation via intramolecular N-H⋯O and O-H⋯N hydrogen bonds; the terminal phenyl ring and the hydroxylphenyl ring are twisted with respect to the central benzene ring by 44.43 (7) and 21.99 (8)°, respectively. In the crystal, molecules are linked by N-H⋯O hydrogen bonds, weak C-H⋯O hydrogen bonds and weak C-H⋯π interactions into a three-dimensional supramolecular network

Discovery of thermonuclear (Type I) X-ray bursts in the X-ray binary Swift J1858.6-0814 observed with NICER and NuSTAR

Swift J1858.6-0814 is a recently discovered X-ray binary notable for extremely strong variability (by factors of >100 in soft X-rays) in its discovery state. We present the detection of five thermonuclear (Type I) X-ray bursts from Swift J1858.6-0814, implying that the compact object in the system is a neutron star (NS). Some of the bursts show photospheric radius expansion, so their peak flux can be used to estimate the distance to the system. The peak luminosity, and hence distance, can depend on several system parameters; for the most likely values, a high inclination and a helium atmosphere, D = 12.8(-0.6)(+0.8) kpc, although systematic effects allow a conservative range of 9-18 kpc. Before one burst, we detect a QPO at 9.6 +/- 0.5 mHz with a fractional rms amplitude of 2.2 +/- 0.2 per cent (0.5-10 keV), likely due to marginally stable burning of helium; similar oscillations may be present before the other bursts but the light curves are not long enough to allow their detection. We also search for burst oscillations but do not detect any, with an upper limit in the best case of 15 per cent fractional amplitude (over 1-8 keV). Finally, we discuss the implications of the NS accretor and this distance on other inferences which have been made about the system. In particular, we find that Swift J1858.6-0814 was observed at super-Eddington luminosities at least during bright flares during the variable stage of its outburst