786 research outputs found
A Conceptual Design and Numerical Analysis for a Small-Scale and Low-Cost Plastic Recycling Machine
A new conceptual design for a small-scale and low-cost plastic recycling machine is generated by combining melting part and compression process. Starting with one of the outstanding requirements is in terms of an affordable-priced machine that can perform two processes with high accuracy and capacity, some issues related to balancing among quality, capacity and cost of machine occurred during a discussion. After implementing various designing methods such as Quality Function Deployment, Reverse Engineering, Morphological Matrix and Pugh Method, an idea of final concept about using an electric oven and hydraulic system to melt down and compress plastic tile which has a dimension of 300x300x9 mm was created. The design of concept is divided into two parts which are mechanical and electrical systems. In a mechanical section, the technical drawing and simulation are made to see how machine performs under operation. Besides, we examined the forces that applied in the moulds to evaluate the strength of the system. In heating and electricity section, we chose electrical components, designed oven parameters and conducted the heating simulation on the mould. In addition, the heating and cooling time was calculated based on the principles of thermodynamics and heat transfer. Furthermore, the manufacturing plan is created to estimate the essential resources producing a certain number of heat-forming machines. In general, the machine needs to be prototyped for controlling its main function and finding practical issues. After that, some improvements could be made to enhance efficiency and increase capacity by designing an optimal mould to more heat absorb and reduce post process, calculate and design more efficient oven, create faster lock mechanism and other improvements for an automatizing machine
The camera of the fifth H.E.S.S. telescope. Part I: System description
In July 2012, as the four ground-based gamma-ray telescopes of the H.E.S.S.
(High Energy Stereoscopic System) array reached their tenth year of operation
in Khomas Highlands, Namibia, a fifth telescope took its first data as part of
the system. This new Cherenkov detector, comprising a 614.5 m^2 reflector with
a highly pixelized camera in its focal plane, improves the sensitivity of the
current array by a factor two and extends its energy domain down to a few tens
of GeV.
The present part I of the paper gives a detailed description of the fifth
H.E.S.S. telescope's camera, presenting the details of both the hardware and
the software, emphasizing the main improvements as compared to previous
H.E.S.S. camera technology.Comment: 16 pages, 13 figures, accepted for publication in NIM
The dust un-biased cosmic star formation history from the 20 cm VLA-COSMOS survey
We derive the cosmic star formation history (CSFH) out to z=1.3 using a
sample of ~350 radio-selected star-forming galaxies, a far larger sample than
in previous, similar studies. We attempt to differentiate between radio
emission from AGN and star-forming galaxies, and determine an evolving 1.4 GHz
luminosity function based on these VLA-COSMOS star forming galaxies. We
precisely measure the high-luminosity end of the star forming galaxy luminosity
function (SFR>100 M_Sol/yr; equivalent to ULIRGs) out to z=1.3, finding a
somewhat slower evolution than previously derived from mid-infrared data. We
find that more stars are forming in luminous starbursts at high redshift. We
use extrapolations based on the local radio galaxy luminosity function;
assuming pure luminosity evolution, we derive
or , depending on the choice of the local
radio galaxy luminosity function. Thus, our radio-derived results independently
confirm the ~1 order of magnitude decline in the CSFH since z~1.Comment: 9 pages, 7 figures; submitted to ApJ (revised following the referee
report
Facile Solution Route to Synthesize Nanostructure Li 4
High rate Li-ion batteries have been given great attention during the last decade as a power source for hybrid electric vehicles (HEVs, EVs, etc.) due to the highest energy and power density. These lithium batteries required a new design of material structure as well as innovative electrode materials. Among the promising candidates, spinel Li4Ti5O12 has been proposed as a high rate anode to replace graphite anode because of high capacity and a negligible structure change during intercalation of lithium. In this work, we synthesized a spinel Li4Ti5O12 in nanosize by a solution route using LiOH and Ti(OBu)4 as precursor. An evaluation of structure and morphology by XRD and SEM exhibited pure spinel phase Li4Ti5O12 and homogenous nanoparticles around 100 nm. In the charge-discharge test, nanospinel Li4Ti5O12 presents excellent discharge capacity 160 mAh/g at rate C/10, as well as good specific capacities of 120, 110, and 100 mAh/g at high rates C, 5C and 10C, respectively
Facile Solution Route to Synthesize Nanostructure Li 4 Ti 5 O 12 for High Rate Li-Ion Battery
High rate Li-ion batteries have been given great attention during the last decade as a power source for hybrid electric vehicles (HEVs, EVs, etc.) due to the highest energy and power density. These lithium batteries required a new design of material structure as well as innovative electrode materials. Among the promising candidates, spinel Li 4 Ti 5 O 12 has been proposed as a high rate anode to replace graphite anode because of high capacity and a negligible structure change during intercalation of lithium. In this work, we synthesized a spinel Li 4 Ti 5 O 12 in nanosize by a solution route using LiOH and Ti(OBu) 4 as precursor. An evaluation of structure and morphology by XRD and SEM exhibited pure spinel phase Li 4 Ti 5 O 12 and homogenous nanoparticles around 100 nm. In the charge-discharge test, nanospinel Li 4 Ti 5 O 12 presents excellent discharge capacity 160 mAh/g at rate C/10, as well as good specific capacities of 120, 110, and 100 mAh/g at high rates C, 5C and 10C, respectively
Molecular Gas in the z=1.2 Ultraluminous Merger GOODS J123634.53+621241.3
We report the detection of CO(2-1) emission from the z=1.2 ultraluminous
infrared galaxy (ULIRG) GOODS J123634.53+621241.3 (also known as the
sub-millimeter galaxy GN26). These observations represent the first discovery
of high-redshift CO emission using the new Combined Array for Research in
Millimeter-Wave Astronomy (CARMA). Of all high-redshift (z>1) galaxies within
the GOODS-North field, this source has the largest far-infrared (FIR) flux
observed in the Spitzer 70um and 160um bands. The CO redshift confirms the
optical identification of the source, and the bright CO(2-1) line suggests the
presence of a large molecular gas reservoir of about 7x10^10 M(sun). The
infrared-to-CO luminosity ratio of L(IR)/L'(CO) = 80+/-30 L(sun) (K Km/s
pc^2)^-1 is slightly smaller than the average ratio found in local ULIRGs and
high-redshift sub-millimeter galaxies. The short star-formation time scale of
about 70 Myr is consistent with a starburst associated with the merger event
and is much shorter than the time scales for spiral galaxies and estimates made
for high-redshift galaxies selected on the basis of their B-z and z-K colors.Comment: Accepted for publication in ApJ Letter
Spitzer 70 and 160-micron Observations of the COSMOS Field
We present Spitzer 70 and 160 micron observations of the COSMOS Spitzer
survey (S-COSMOS). The data processing techniques are discussed for the
publicly released products consisting of images and source catalogs. We present
accurate 70 and 160 micron source counts of the COSMOS field and find
reasonable agreement with measurements in other fields and with model
predictions. The previously reported counts for GOODS-North and the
extragalactic First Look Survey are updated with the latest calibration, and
counts are measured based on the large area SWIRE survey to constrain the
bright source counts. We measure an extragalactic confusion noise level of
sigma_c = 9.4+/-3.3 mJy (q=5) for the MIPS 160-micron band based on the deep
S-COSMOS data and report an updated confusion noise level of sigma_c =
0.35+/-0.15 mJy (q=5) for the MIPS 70-micron band.Comment: Accepted AJ, 15 Aug. 2009. Data available at
http://spider.ipac.caltech.edu/staff/frayer/mycosmos/ until released by IRS
Mid- and Far-infrared Luminosity Functions and Galaxy Evolution from Multiwavelength Spitzer Observations up to z~2.5
[Abridged]We exploit a large homogeneous dataset to derive a self-consistent
picture of IR emission based on the time-dependent 24, 15, 12 and 8micron
monochromatic and bolometric IR luminosity functions (LF) over the 0<z<2.5
redshift range. Our analysis is based on the combination of data from deep
Spitzer surveys in the VVDS-SWIRE and GOODS areas. To our limiting flux of
S(24)=400microJy our derived sample in VVDS-SWIRE includes 1494 sources, and
666 and 904 sources brighter than S(24)=80microJy are catalogued in GOODS-S and
GOODS-N, respectively, for a total area of ~0.9 square degs. We obtain reliable
optical identifications and redshifts, providing us a rich and robust dataset
for our luminosity function determination. Based on the multi-wavelength
information available, we constrain the LFs at 8, 12, 15 and 24micron. We also
extrapolate total IR luminosities from our best-fit to the observed SEDs of
each source, and use this to derive the bolometric LF and comoving volume
emissivity up to z~2.5. In the 0<z<1 interval, the bolometric IR luminosity
density evolves as (1+z)^3.8+/-0.4. Although more uncertain at higher-z, our
results show a flattening of the IR luminosity density at z>1. The mean
redshift of the peak in the source number density shifts with luminosity: the
brighest IR galaxies appear to be forming stars earlier in cosmic time (z>1.5),
while the less luminous ones keep doing it at more recent epochs (z~1 for
L(IR)<10^11L_sun). Our results suggest a rapid increase of the galaxy IR
comoving volume emissivity back to z~1 and a constant average emissivity at
z>1. We also seem to find a difference in the evolution rate of the source
number densities as a function of luminosity, a downsizing evolutionary pattern
similar to that reported from other samples of cosmic sources.Comment: Accepted for pubblicantion in Astronomy and Astrophysic
Cadmium accumulation and interactions with zinc, copper, and manganese, analysed by ICP-MS in a long-term Caco-2 TC7 cell model
The influence of long-term exposure to cadmium (Cd) on essential minerals was investigated using a Caco-2
TC7 cells and a multi-analytical tool: microwave digestion and inductively coupled plasma mass spectrometry.
Intracellular levels, effects on cadmium accumulation, distribution, and reference concentration
ranges of the following elements were determined: Na, Mg, Ca, Cr, Fe, Mn, Co, Ni, Cu, Zn, Mo, and Cd.
Results showed that Caco-2 TC7 cells incubated long-term with cadmium concentrations ranging from 0 to
10 lmol Cd/l for 5 weeks exhibited a significant increase in cadmium accumulation. Furthermore, this
accumulation was more marked in cells exposed long-term to cadmium compared with controls, and that
this exposure resulted in a significant accumulation of copper and zinc but not of the other elements
measured. Interactions of Cd with three elements: zinc, copper, and manganese were particularly studied.
Exposed to 30 lmol/l of the element, manganese showed the highest inhibition and copper the lowest on
cadmium intracellular accumulation but Zn, Cu, and Mn behave differently in terms of their mutual
competition with Cd. Indeed, increasing cadmium in the culture medium resulted in a gradual and significant
increase in the accumulation of zinc. There was a significant decrease in manganese from 5 lmol
Cd/l exposure, and no variation was observed with copper.
Abbreviation: AAS – Atomic absorption spectrometry; CRM– Certified reference material; PBS – Phosphate
buffered saline without calcium and magnesium; DMEM – Dubelcco’s modified Eagle’s medium
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