649 research outputs found
Preparation of Metal Immobilized Orange Waste Gel for Arsenic(V) Removal From Water
- The toxicity of arsenic is known to be a risk to aquatic flora and fauna and to human health even in relatively low concentration. In this research an adsorption gel was prepared from agricultural waste material (orange waste) through simple chemical modification in the view to remove arsenic (V) from water. Orange waste was crushed into small particles and saponified with Ca(OH)2 to prepare saponified orange waste, which was further modified by immobilizing gadolinium(III) to obtain desired adsorption material (Gd(III)-immobilized SOW gel). The effective pH range for arsenic adsorption was found to be 7.5 – 8.5. Adsorption capacity of the gel was evaluated to be 0.45 mol-arsenic (V)/kg. Dynamic adsorption of arsenic (V) in column-mode was conducted and a dynamic capacity was found to be 0.39 mol/kg. Elution of arsenate was tested after complete saturation of the column packed with gadolinium-immobilized orange waste adsorption gel. A complete elution of arsenate was achieved with the help of 1 M HCl and 28 times pre-concentration factor was attained. This study showed that a cheap and abundant agro-industrial waste material could be successfully employed for the remediation of arsenic pollution in aquatic environment
Line Evolution of the Nova V5587 Sgr from Early to Nebula Phase
The spectral evolution of the nova V5587 Sgr has been monitored at Koyama Astronomical Observatory and Higashi-Hiroshima Observatory, Japan, from the early to nebula phase. The nova rebrightened several times. The spectra during the early phase showed emission lines of H α, H β, O I, He I, He II, N II, Fe II. Nova V5587 Sgr is classified into the Fe II type. The helium abundance of the nova is estimated as N(He)/N(H) = 0.134 ± 0.09. The light curve, the spectral evolution, and the helium abundance in V5587 Sgr are similar to those of the nova PW Vul
Liquid-like thermal conduction in a crystalline solid
A solid conducts heat through both transverse and longitudinal acoustic
phonons, but a liquid employs only longitudinal vibrations. Here, we report
that the crystalline solid AgCrSe2 has liquid-like thermal conduction. In this
compound, Ag atoms exhibit a dynamic duality that they are exclusively involved
in intense low-lying transverse acoustic phonons while they also undergo local
fluctuations inherent in an order-to-disorder transition occurring at 450 K. As
a consequence of this extreme disorder-phonon coupling, transverse acoustic
phonons become damped as approaching the transition temperature, above which
they are not defined anymore because their lifetime is shorter than the
relaxation time of local fluctuations. Nevertheless, the damped longitudinal
acoustic phonon survives for thermal transport. This microscopic insight might
reshape the fundamental idea on thermal transport properties of matter and
facilitates the optimization of thermoelectrics.Comment: four figures, supplemental informatio
Spectroscopic Monitoring Observations of Nova V1724 Aql in 2012
Spectroscopic and photometric monitoring observations of nova Apl 2012 (V1724 Apl) were conducted at Koyama Astronomical Observatory, Fujii-Kurosaki Observatory and Bisei Astronomical Observatory. The nova was initially considered as an outbursting pre-main-sequence young stellar object. Our monitoring observations have revealed the nova to be a Fe II type classical nova. The temporal evolution of spectra and light curves of the nova were similar to those of a slow nova (e.g., V1280 Sco and V5558 Sgr). We observed no evidence of molecule formation in V1724 Aql in contrast with V2676 Oph in which dust formation occurred after the molecular formation in the nova outflow
Amniotic membrane transplantation for wound dehiscence after deep lamellar keratoplasty: a case report
<p>Abstract</p> <p>Purpose</p> <p>To report amniotic membrane (AM) transplantation in a patient with wound dehiscence 5 months after deep lamellar keratoplasty (DLKP)</p> <p>Methods</p> <p>The patient was an 84-year-old Japanese man who had undergone right DLKP 5 months earlier for central corneal scarring due to recurrent stromal herpetic keratitis. He developed wound dehiscence with corneal stromal melting due to recurrence of stromal herpes in both the donor and recipient sites. "AM roll-in filling technique" and AM patching were performed.</p> <p>Results</p> <p>Following AM transplantation, stromal inflammation subsided and complete epithelization occurred within 10 days of surgery.</p> <p>At 8 months postoperatively, biomicroscopy revealed stable wound apposition or stromal gain. Following AM transplantation, stromal inflammation subsided and complete epithelialization was achieved within 10 days after surgery.</p> <p>Conclusion</p> <p>AM transplantation may offer an effective treatment modality for herpetic corneal wound dehiscence after DLKP.</p
Recent Searches for the Radio Lines of NH_3 in Comets
Radio observations in the ammonia inversion lines of four comets, C/2001 A2
(LINEAR), 153P/Ikeya-Zhang, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), were
performed at the Effelsberg 100-m Radio Telescope during their respective close
approaches to Earth. None of the four lowest energy metastable lines
(J,K=J),J=1--4, could be detected in these comets. We derive the following 3
sigma upper bounds on the NH_3 production rate, and c omparing to the
corresponding water production rates, percentage NH_3 abundances relative to
H_2O:
Q(NH_3) < 1.9x10^26 s^-1 (0.63%) for C/2001 A2 (LINEAR),
Q(NH_3) < 2.7x10^26 s^-1 (0.13%) for C/2001 Q4 (NEAT),
Q(NH_3) < 2.3x10^27 s^-1 (0.74%) for C/2002 T7 (LINEAR) and Q(NH_3) <=
6.3x10^26 s^-1 (0.63%) for Comet 153P/Ikeya-Zhang.
At 0.74% or less, the ammonia-to-water ratios are factors of 2 below the
value for C/1995 O1 (Hale-Bopp) and 1P/Halley, suggesting chemical diversity
between comets. The 18-cm lines of OH were clearly detected in the two comets
observed during the 2004 campaign, thereby validating the cometary ephemerides.Comment: 8 pages, 3 figure
Chandra Observations of Type Ia Supernovae: Upper Limits to the X-ray Flux of SN 2002bo, SN 2002ic, SN 2005gj, and SN 2005ke
We set sensitive upper limits to the X-ray emission of four Type Ia
supernovae (SNe Ia) using the Chandra X-ray Observatory. SN 2002bo, a normal,
although reddened, nearby SN Ia, was observed 9.3 days after explosion. For an
absorbed, high temperature bremsstrahlung model the flux limits are 3.2E-16
ergs/cm^2/s (0.5-2 keV band) and 4.1E-15 ergs/cm^2/s (2-10 keV band). Using
conservative model assumptions and a 10 km/s wind speed, we derive a mass loss
rate of \dot{M} ~ 2E-5 M_\odot/yr, which is comparable to limits set by the
non-detection of Halpha lines from other SNe Ia. Two other objects, SN 2002ic
and SN 2005gj, observed 260 and 80 days after explosion, respectively, are the
only SNe Ia showing evidence for circumstellar interaction. The SN 2002ic X-ray
flux upper limits are ~4 times below predictions of the interaction model
currently favored to explain the bright optical emission. To resolve this
discrepancy we invoke the mixing of cool dense ejecta fragments into the
forward shock region, which produces increased X-ray absorption. A modest
amount of mixing allows us to accommodate the Chandra upper limit. SN 2005gj is
less well studied at this time. Assuming the same circumstellar environment as
for SN 2002i, the X-ray flux upper limits for SN 2005gj are ~4 times below the
predictions, suggesting that mixing of cool ejecta into the forward shock has
also occurred here. Our reanalysis of Swift and Chandra data on SN 2005ke does
not confirm a previously reported X-ray detection. The host galaxies NGC 3190
(SN 2002bo) and NGC 1371 (SN 2005ke) each harbor a low luminosity (L_X ~ 3-4E40
ergs/s) active nucleus in addition to wide-spread diffuse soft X-ray emission.Comment: 16 pages, to appear in ApJ (20 Nov 2007
- …