The document describes the fabrication of thin barium targets through vacuum evaporation for use in a nuclear physics experiment. Barium metal was evaporated onto carbon backings in a diffusion pump-based coating unit. The barium was evaporated using resistive heating, while carbon was deposited via electron beam bombardment. Several steps were taken to deposit barium and then cap it with carbon in vacuum to protect it from oxidation due to air exposure. The fabricated barium targets were 200-240 micrograms per square centimeter thick.
Definition of coating,advantages of coating, types of coating,brief explanation of each type of coating giving process aaplication advatanges about organic coating, inorganic coating,metallic coating,conversion coating, precoated metals coating hot dipping, electroplating
Definition of coating,advantages of coating, types of coating,brief explanation of each type of coating giving process aaplication advatanges about organic coating, inorganic coating,metallic coating,conversion coating, precoated metals coating hot dipping, electroplating
Designing of a plug flow reactor for so2Rizwan Yaseen
The General Designing Specs of Packed Bed Reactor.
The Presentation Highlights 50 TPD H2SO4 Sulpur Converter i presented during Graduation. Aspen hysys is Also used to check pressure drop in a reactor
The lowest possible surface resistivity and higher accelerating field are the paramount
considerations, hence are obligatory for accelerating cavities. Since, superconducting materials
are used to make radio-frequency cavities for future accelerators. In the case of rf cavities,
superconductors are being used in order to minimize the power dissipated and increase the
figures of merit of a radio-frequency cavity, such as the quality factor and accelerating gradient.
Hence, these could be achieved by improving surface treatment to the cavity, and processing
techniques must be analyzed in order to optimize these figures of merit.
The research work reported in this dissertation mainly carried out on tesla type seamless 6GHz
Nb and Cu cavities. We have developed two innovative techniques: firstly, for mechanical
polishing of cavities, and secondly for purification of these cavities at atmospheric pressure under
cover of 4Helium gas (for protection) and at ultra-high vacuum (UHV) system. These cavities are
fabricated by spinning technology to create seamless cavities.
The main advantages of 6 GHz bulk-Nb cavities are saving cost, materials and time to collect
statistics of surface treatments and RF test in a very short time scale. Cavities are RF tested
before and after high temperature treatment under atmospheric pressure (under cover of inert gas
atmosphere to protect inner and outer surface of cavity) inside transparent quartz tube, and under
UHV conditions. Induction heating method is used to anneal the cavity at temperatures higher
than 2000°C and close to the melting point of Nb for less than a minute while few seconds at
maximum temperature. Before RF test and UHV annealing, the surface treatment processes like
tumbling, chemical, electro-chemical (such as BCP and EP), ultrasonic cleaning and high
pressure rinsing (HPR) have been employed. High temperature treatment for few minutes at
atmospheric pressure allow to reduce hydrogen, oxygen and other elemental impurities, which
effects on cavity Q-factor degradation, hence recovers rf performances of these cavities. This
research work will address these problems and illustrate the importance of surface treatments.
Graphene_complete description_Introduction_history_synthesis_electrical appliactions other other miscellineus applcations,challeneges explained with full of animated diagrams.
If you need in PPT file with full of beautiful animations and transitions for FREE, then just email me on this adress:
kashifwattu798@gmail.com
ENJOY ...!!!
it contain some primary information about carbon black and its manufacturing process... not in detail but just overview...
hope you will find it helpful...
Designing of a plug flow reactor for so2Rizwan Yaseen
The General Designing Specs of Packed Bed Reactor.
The Presentation Highlights 50 TPD H2SO4 Sulpur Converter i presented during Graduation. Aspen hysys is Also used to check pressure drop in a reactor
The lowest possible surface resistivity and higher accelerating field are the paramount
considerations, hence are obligatory for accelerating cavities. Since, superconducting materials
are used to make radio-frequency cavities for future accelerators. In the case of rf cavities,
superconductors are being used in order to minimize the power dissipated and increase the
figures of merit of a radio-frequency cavity, such as the quality factor and accelerating gradient.
Hence, these could be achieved by improving surface treatment to the cavity, and processing
techniques must be analyzed in order to optimize these figures of merit.
The research work reported in this dissertation mainly carried out on tesla type seamless 6GHz
Nb and Cu cavities. We have developed two innovative techniques: firstly, for mechanical
polishing of cavities, and secondly for purification of these cavities at atmospheric pressure under
cover of 4Helium gas (for protection) and at ultra-high vacuum (UHV) system. These cavities are
fabricated by spinning technology to create seamless cavities.
The main advantages of 6 GHz bulk-Nb cavities are saving cost, materials and time to collect
statistics of surface treatments and RF test in a very short time scale. Cavities are RF tested
before and after high temperature treatment under atmospheric pressure (under cover of inert gas
atmosphere to protect inner and outer surface of cavity) inside transparent quartz tube, and under
UHV conditions. Induction heating method is used to anneal the cavity at temperatures higher
than 2000°C and close to the melting point of Nb for less than a minute while few seconds at
maximum temperature. Before RF test and UHV annealing, the surface treatment processes like
tumbling, chemical, electro-chemical (such as BCP and EP), ultrasonic cleaning and high
pressure rinsing (HPR) have been employed. High temperature treatment for few minutes at
atmospheric pressure allow to reduce hydrogen, oxygen and other elemental impurities, which
effects on cavity Q-factor degradation, hence recovers rf performances of these cavities. This
research work will address these problems and illustrate the importance of surface treatments.
Graphene_complete description_Introduction_history_synthesis_electrical appliactions other other miscellineus applcations,challeneges explained with full of animated diagrams.
If you need in PPT file with full of beautiful animations and transitions for FREE, then just email me on this adress:
kashifwattu798@gmail.com
ENJOY ...!!!
it contain some primary information about carbon black and its manufacturing process... not in detail but just overview...
hope you will find it helpful...
Heat treatment 2 by
P.SENTHAMARAI KANNAN,
ASSISTANT PROFESSOR ,
DEPARTMENT OF MECHANICAL ENGINEERING,
KAMARAJ COLLEGE OF ENGINEERING AND TECHNOLOGY,
VIRUDHUNAGAR, TAMILNADU.
INDIA.
Experimental Investigation on Adsorption Capacity of a Variety of Activated C...IJERA Editor
This study aims to develop a device with minimum heat and mass transfer limitations between adsorbent and
adsorbate, and subsequently to obtain practically applicable adsorption capacity data. Also, 5 kW adsorption
chillers (evaporators, condensers and adsorbers) are designed based on the experimental output data of the whole
tested pairs. A finned-tube heat exchanger was employed and installed at the center adsorber, and each employed
adsorbent was immobilized on its surfaces by using an adhesive agent. A variety of pairs: are activated carbon
powder (ACP)/R-134a, ACP/R-407c, ACP/R-507A, activated carbon granules (ACG)/R-507A, ACG /R-407c
and ACG /R-134a, were examined at different adsorption temperatures of 25, 30, 35 and 50°C. It was found that,
at the adsorption temperature of 25°C the maximum adsorption capacity was 0.8352 kg kg-1 for ACP/R-134a,
while at the adsorption temperature of 50°C the maximum adsorption capacity was 0.3207 kg kg-1 for ACP/R-
134a. Therefore, the ACP/R-134a pair is highly recommended to be employed as adsorption refrigeration
working pair because of its higher maximum adsorption capacity higher than the other examined pairs.
Vapor growth of binary and ternary phosphorus-based semiconductors into TiO2 ...Pawan Kumar
We report successful synthesis of low band gap inorganic polyphosphide and TiO2 heterostructures with the aid of short-way transport reactions. Binary and ternary polyphosphides (NaP7, SnIP, and (CuI)3P12) were successfully reacted and deposited into electrochemically fabricated TiO2 nanotubes. Employing vapor phase reaction deposition, the cavities of 100 μm long TiO2 nanotubes were infiltrated; approximately 50% of the nanotube arrays were estimated to be infiltrated in the case of NaP7. Intensive characterization of the hybrid materials with techniques including SEM, FIB, HR-TEM, Raman spectroscopy, XRD, and XPS proved the successful vapor phase deposition and synthesis of the substances on and inside the nanotubes. The polyphosphide@TiO2 hybrids exhibited superior water splitting performance compared to pristine materials and were found to be more active at higher wavelengths. SnIP@TiO2 emerged to be the most active among the polyphosphide@TiO2 materials. The improved photocatalytic performance might be due to Fermi level re-alignment and a lower charge transfer resistance which facilitated better charge separation from inorganic phosphides to TiO2.
Technological characteristics of the calcined limestonecesar hernandez
The gray-green limestone from Agios Panteleimonas
is studied in this paper after submitting it in special technological
analyses in order to determine the possibility
for quicklime production. Cubic test specimens with
mean 50 mm edge length were calcined at 850, 950 and
1,050~ with 150 rain preheating time and 120 rain
retention time at each calcination temperature. At the
dissociation temperature of pure calcite (898~ only
one half of the initial limestone has been calcined. The
dissociation of the specimens started at 740~ and
almost completed at 1,050~ Probably, the large edge
length of the cubic specimens and the low retention
time are responsible for the incomplete calcination at
1,050~ The dry apparent weight of the calcined limestone
(1.577 g/cm3), its low shrinkage (0.1-0.3%), the
2% impurities content and the 24% value of the attrition
and abrasion resistance, characterize this quicklime
and classify it to the high quality products.
Vapor Deposition of Semiconducting Phosphorus Allotropes into TiO2 Nanotube A...Pawan Kumar
Recent evidence of exponential environmental degradation will demand a drastic shift in research and development toward exploiting alternative energy resources such as solar energy. Here, we report the successful low-cost and easily accessible synthesis of hybrid semiconductor@TiO2 nanotube photocatalysts. In order to realize its maximum potential in harvesting photons in the visible-light range, TiO2 nanotubes have been loaded with earth-abundant, low-band-gap fibrous red and black phosphorus (P). Scanning electron microscopy– and scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron microscopy, and UV–vis measurements have been performed, substantiating the deposition of fibrous red and black P on top and inside the cavities of 100-μm-long electrochemically fabricated nanotubes. The nanotubular morphology of titania and a vapor-transport technique are utilized to form heterojunctions of P and TiO2. Compared to pristine anatase 3.2 eV TiO2 nanotubes, the creation of heterojunctions in the hybrid material resulted in 1.5–2.1 eV photoelectrocatalysts. An enhanced photoelectrochemical water-splitting performance under visible light compared with the individual components resulted for the P@TiO2 hybrids. This feature is due to synergistically improved charge separation in the heterojunction and more effective visible-light absorption. The electronic band structure and charge-carrier dynamics are investigated in detail using ultraviolet photoelectron spectroscopy and Kelvin probe force microscopy to elucidate the charge-separation mechanism. A Fermi-level alignment in P@TiO2 heterojunctions leads to a more reductive flat-band potential and a deeper valence band compared to pristine P and thus facilitates a better water-splitting performance. Our results demonstrate effective conversion efficiencies for the nanostructured hybrids, which may enable future applications in optoelectronic applications such as photodetectors, photovoltaics, photoelectrochemical catalysts, and sensors.
1. FABRICATION OF THIN TARGET OF 138
Ba BY VACUUM
EVAPORATION.
K.K. Rajesh1*
, M.M.Hosamani 2
, A. Shamlath3
, Abhilash S.R. 4
, N.Madhavan4
,
M.M.Musthafa1
, D. Kabiraj4
1
University of Calicut, Calicut, Kerala
2 Karnatak University,Dharwad, Karnataka
3
Central University of Kerala, Nileswar, Kerala
4 Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi
. * email: rajeshmlpm@yahoo.com
Introduction
Target fabrication is a highly
sophisticated and crucial step in nuclear
physics experiments. The success of any
nuclear experiment is primarily determined by
the quality and quantity of the target. 138
Ba
target is prepared for the evaporation residue
cross section measurement of 188
Pt populated
through the reaction with 50
Ti ion beam.
Barium is a highly reactive metal and upon
exposure to air at room temperature it will
readily react with oxygen. Presently no
information is available in the literature for
the thin barium target fabrication through
vacuum evaporation method. The two
previous attempts available in literature [1, 2]
were in sputtering method using barium
nitrate or barium carbonate.
Experimental Set up
A diffusion pump based coating unit at
IUAC, NewDelhi was used for target
fabrication. It can provide a pressure of the
order of 10-7
mbar. It is equipped with a
resistive heating evaporator assembly and
electron beam bombardment assembly side by
side. In order to make the films of uniform
thickness the deposition rate has to be kept as
low as possible. So it is essential to monitor
the thickness of the film being deposited and
hence a quartz crystal monitor is used for this
purpose. Chances are high that the oil particles
from the diffusion pump may contaminate the
target surface while operation [3]. So a liquid
nitrogen (LN2) cold trap is incorporated to
isolate the bell jar from diffusion pump as
shown in figure1.
Figure 1. A schematic diagram of diffusion
pump based coating unit at IUAC.
Target Fabrication
Thin targets are generally fabricated on
a carbon backing with barium chloride or
teepol as parting agent. The very high
reactivity of barium towards oxygen
demanded a capping. The following steps are
followed in the target making. 1) deposition of
BaCl2 as parting agent on a glass substrate 2)
deposition of carbon over BaCl2 3) deposition
of 138
Ba metal over carbon backing and 4)
deposition of carbon over 138
Ba as capping.
A thick graphite rod of length 8mm and
diameter 6mm was irradiated with electron
Proceedings of the DAE-BRNS Symp. on Nucl. Phys. 60 (2015) 532
Available online at www.sympnp.org/proceedings
2. beam to produce carbon films. This way we
produced carbon films of thickness varying
from 20μg/cm2
to 52μg/cm2
. The thickness of
the carbon film was verified by alpha energy
loss method with the help of a 241
Am alpha
source.
The carbon capping on the barium
was done without disturbing the vacuum
because of its high reactivity. For maximum
deposition of the barium, the distance between
the substrate holder and the source must be
minimum and for carbon deposition it must be
maximum to keep the barium deposited slides
safe from the high melting point of the carbon.
Barium evaporation was done with resistive
heating method and carbon evaporation by
electron beam bombardment.
Figure 2. Electron gun assembly and resistive
heating assembly of the diffusion pump based
coating unit.
A tantalum tubular boat was used for the
evaporation of 33.23mg of barium metal. The
deposition rate in the detector was initially
null until around 80A current and became
quick at around 100A and after that it was
almost a constant till 150A. Throughout the
process the pressure was maintained around
10-7
mbar. Since the deposition rate was kept
as minimum as possible, it took almost 8
hours for the deposition to complete at 1.0V
potential difference.
For the carbon capping the substrate
holder was rotated through 30 degrees to shift
it from barium source to carbon source. Then
it was raised by 2.5cm to protect the barium
deposited plane glass slide from high melting
point of carbon. The longitudinal movement
and rotary movement of the substrate was
done by a rotary motion feed through. A
shutter or shield was also used to control the
deposition. A capping thickness of about
10μg/cm2
was achieved in about 45minutes.
The vacuum chamber was vented with argon
gas before it was opened and the slides were
annealed at 325°C for an hour to remove any
stress developed. It was floated in warm water
at 53°C and was taken on target holders. The
floating was done quickly to minimise the
reaction with water. The eight targets so
prepared were shifted to a desiccator in argon
environment. The thickness of these 138
Ba
metal targets were found to be varying from
200μg/cm2
to 240μg/cm2
.
References
[1] Jan Van Audenhove(Edtd.), News
Letter,Target Development Society,Pages3
and 7, December 1981.
[2] M.L. Smith(Edtd.), Proceedings of the
seminar on the preparation and standardisation
of isotopic targets and foils,page12, October
1965.
[3] Savi Goyal et al. Nuclear Instruments and
Methods in Physics Research A777(2015).
[4]Yaffe,AnnualReviewofNuclearScience12
(1962)153.
Proceedings of the DAE-BRNS Symp. on Nucl. Phys. 60 (2015) 533
Available online at www.sympnp.org/proceedings