Foundation Reinforcement of Old ALA Building

In Northern Tehran, a 100- years old residential masonry building is being renovated into a public library. The wooden floors of the upper story are being reinforced with an exposed steel space - frame and for settlement prevention of old bearing walls, the end bearing piles are used. During the construction of a reflective pool very close to the building, a number of masonry foundations begun sliding from under the brick columns of the main facade. In order to stop the sliding and prevent damage to the building a design was proposed to reinforce the foundation. The paper, examines the position of the building and the reflective pool, shows the way by which the foundation sliding was stopped and how it generally helped the whole building foundation

A population study of type II bursts in the Rapid Burster

Type II bursts are thought to arise from instabilities in the accretion flow onto a neutron star in an X-ray binary. Despite having been known for almost 40 years, no model can yet satisfactorily account for all their properties. To shed light on the nature of this phenomenon and provide a reference for future theoretical work, we study the entire sample of Rossi X-ray Timing Explorer data of type II bursts from the Rapid Burster (MXB 1730-335). We find that type II bursts are Eddington-limited in flux, that a larger amount of energy goes in the bursts than in the persistent emission, that type II bursts can be as short as 0.130 s, and that the distribution of recurrence times drops abruptly below 15-18 s. We highlight the complicated feedback between type II bursts and the NS surface thermonuclear explosions known as type I bursts, and between type II bursts and the persistent emission. We review a number of models for type II bursts. While no model can reproduce all the observed burst properties and explain the source uniqueness, models involving a gating role for the magnetic field come closest to matching the properties of our sample. The uniqueness of the source may be explained by a special combination of magnetic field strength, stellar spin period and alignment between the magnetic field and the spin axis.Comment: Accepted 2015 February 12. Received 2015 February 10; in original form 2014 December 1

Foundation Sign Correction in Stochastic Analysis Procedures

There are “ABS, SRSS, CQC, MSRSS…” methods in stochastic analysis of structures, that are based on the mean of the response squares. One of the most accurate stochastic methods is MSRSS, that is defined as equation (1). E[y2]=∑j=1N Rj2 + 2 ∑k=j+1NRjk The maximum modal responses are positive or singles, and therefore direction of the forces act on the foundation are alike. In these cases foundation analysis is not valid and the force sign correction must be used. In this paper, besides considering the stochastic methods shortly, a method for sign correction based on the time history analysis will be presented

A XMM-Newton observation during the 2000 outburst of SAX J1808.4-3658

I present a XMM-Newton observation of the accretion driven millisecond X-ray pulsar SAX J1808.4-3658 during its 2000 outburst. The source was conclusively detected, albeit at a level of only ~2 x 10^{32} erg/s. The source spectrum could be fitted with a power-law model (with a photon index of ~2.2), a neutron star atmosphere model (with a temperature of ~0.2 keV), or with a combination of a thermal (either a black-body or an atmosphere model) and a power-law component. During a XMM-Newton observation taken approximately one year later, the source was in quiescence and its luminosity was a factor of ~4 lower. It is possible that the source spectrum during the 2000 outburst was softer than its quiescent 2001 spectrum, however, the statistics of the data do not allow to make a firm conclusion. The results obtained are discussed in the context of the 2000 outburst of SAX J1808.4-3658 and the quiescent properties of the source.Comment: Accepted for publication in ApJ, 15 January 200

Indications for a slow rotator in the Rapid Burster from its thermonuclear bursting behaviour

We perform time-resolved spectroscopy of all the type I bursts from the Rapid Burster (MXB 1730-335) detected with the Rossi X-ray Timing Explorer. Type I bursts are detected at high accretion rates, up to \sim 45% of the Eddington luminosity. We find evidence that bursts lacking the canonical cooling in their time-resolved spectra are, none the less, thermonuclear in nature. The type I bursting rate keeps increasing with the persistent luminosity, well above the threshold at which it is known to abruptly drop in other bursting low-mass X-ray binaries. The only other known source in which the bursting rate keeps increasing over such a large range of mass accretion rates is the 11 Hz pulsar IGR J17480$-$2446. This may indicate a similarly slow spin for the neutron star in the Rapid Burster

Achromatic late-time variability in thermonuclear X-ray bursts - an accretion disk disrupted by a nova-like shell?

An unusual Eddington-limited thermonuclear X-ray burst was detected from the accreting neutron star in 2S 0918-549 with the Rossi X-ray Timing Explorer. The burst commenced with a brief (40 ms) precursor and maintained near-Eddington fluxes during the initial 77 s. These characteristics are indicative of a nova-like expulsion of a shell from the neutron star surface. Starting 122 s into the burst, the burst shows strong (87 +/- 1% peak-to-peak amplitude) achromatic fluctuations for 60 s. We speculate that the fluctuations are due to Thompson scattering by fully-ionized inhomogeneities in a resettling accretion disk that was disrupted by the effects of super-Eddington fluxes. An expanding shell may be the necessary prerequisite for the fluctuations.Comment: 7 pages, 4 figures. Submitted to A&

A new bursting X-ray transient: SAX J1750.8-2900

We have analysed in detail the discovery measurements of the X-ray burster SAX J1750.8-2900 by the Wide Field Cameras on board BeppoSAX in spring 1997, at a position ~1.2 degrees off the Galactic Centre. The source was in outburst on March 13th when the first observation started and showed X-ray emission for ~ 2 weeks. A total of 9 bursts were detected, with peak intensities varying from ~ 0.4 to 1.0 Crab in the 2-10 keV range. Most bursts showed a fast rise time (~ 1s), an exponential decay profile with e-folding time of ~ 5s, spectral softening during decay, and a spectrum which is consistent with few keV blackbody radiation. These features identify them as type-I X-ray bursts of thermonuclear origin. The presence of type-I bursts and the source position close to the Galactic Centre favours the classification of this object as a neutron star low mass X-ray binary. X-ray emission from SAX J1750.8-2900 was not detected in the previous and subsequent Galactic bulge monitoring, and the source was never seen bursting again.Comment: 13 pages, 3 Postscript figures, aaspp4 styl

Identification of the optical and quiescent counterparts to the bright X-ray transient in NGC 6440

After 3 years of quiescence, the globular cluster NGC 6440 exhibited a bright transient X-ray source turning on in August 2001, as noted with the RXTE All-Sky Monitor. We carried out a short target of opportunity observation with the Chandra X-ray Observatory and are able to associate the transient with the brightest of 24 X-ray sources detected during quiescence in July 2000 with Chandra. Furthermore, we securely identify the optical counterpart and determine that the 1998 X-ray outburst in NGC 6440 was from the same object. This is the first time that an optical counterpart to a transient in a globular cluster is securely identified. Since the transient is a type I X-ray burster, it is established that the compact accretor is a neutron star. Thus, this transient provides an ideal case to study the quiescent emission in the optical and X-ray of a transiently accreting neutron star while knowing the distance and reddening accurately. One model that fits the quiescent spectrum is an absorbed power law plus neutron star hydrogen atmosphere model. We find an intrinsic neutron star radius of 17_{-12}^{+31} km and an unabsorbed bolometric luminosity for the neutron star atmosphere of (2.1+/-0.8)E33 erg/s which is consistent with predictions for a cooling neutron star.Comment: Accepted for publication in ApJ Letter

Effect of autoclave processing and gamma irradiation on apparent ileal amino acids digestibility of cottonseed meal in male broiler breeders

The objective of this study was to investigate the effect of autoclaving and different doses of gamma irradiation on the apparent ileal digestibility of amino acids of cottonseed meal in male broiler breeders. Samples were irradiated in a gamma cell at total doses of 15, 30 and 45 kGy. One package (control) was left at room temperature: Similar to the other treatments, evaporation decreased the moisture content of the samples. Autoclaving of cottonseed meal for 15 min at 121°C was studied. The treatments were: (1) control, untreated cottonseed meal diet; (2) autoclaved cottonseed meal diet; (3) cottonseed meal diet gamma irradiated at a dose of 15 kGy; (4) cottonseed meal diet gamma irradiated at a dose of 30 kGy; (5) cottonseed meal diet gamma irradiated at a dose of 45 kGy. The results show that autoclaving for 15 min at 121°C did not have a statistically significant effect on the apparent ileal digestibility of the amino acids in cottonseed meal when compared with the control treatment. The results also show that gamma irradiation of cottonseed meal were not effective in increasing the apparent digestibility of amino acids. In addition, irradiation of cottonseed meal did not improve the apparent digestibility of amino acids in comparison with the other processing methods only, but also significantly decreased it (p<0.05).Key words: Gamma irradiation, digestibility, amino acid, cottonseed meal, broiler