2,373 research outputs found
Novel duplex vapor-electrochemical method for silicon solar cells
Silicon obtained by the SiF4-Na reaction was analyzed by spark source mass spectrometry (SSMS). Silicon samples prepared from induction melted powder were evaluated for electrical properties using four point probe conductivity and thermoelectric methods. SiF4-Na reaction under P sub SiF4 greater than 1 atmosphere. The amount of silicon produced was increased from 25 g per batch (in the glass reactor) to greater than 70 g per batch in the stainless steel reactor. The study of the effects of reaction variables such as P sub SiF4 and maximum temperature attained on the particle size of silicon powder showed that the silicon particle size tends to grow larger with increasing pressure of the SiF4 gas in the reaction system
Novel duplex vapor-electrochemical method for silicon solar cells
Silicon was produced by alternate pulse feeding of the reactants SiF4 gas and liquid sodium. The average temperature in the reactor could be controlled, by regulating the amount of reactant in each pulse. Silicon tetrafluoride gas was analyzed by mass spectrometry to determine the nature and amount of contained volatile impurities which included silicon oxyfluorides, sulfur oxyfluorides, and sulfur dioxide. Sodium metal was analyzed by emission spectrography, and it was found to contain only calcium and copper as impurities
Information entropy and nucleon correlations in nuclei
The information entropies in coordinate and momentum spaces and their sum
(, , ) are evaluated for many nuclei using "experimental"
densities or/and momentum distributions. The results are compared with the
harmonic oscillator model and with the short-range correlated distributions. It
is found that depends strongly on and does not depend very much
on the model. The behaviour of is opposite. The various cases we consider
can be classified according to either the quantity of the experimental data we
use or by the values of , i.e., the increase of the quality of the density
and of the momentum distributions leads to an increase of the values of . In
all cases, apart from the linear relation , the linear relation
also holds. V is the mean volume of the nucleus. If is
considered as an ensemble entropy, a relation between or and the
ensemble volume can be found. Finally, comparing different electron scattering
experiments for the same nucleus, it is found that the larger the momentum
transfer ranges, the larger the information entropy is. It is concluded that
could be used to compare different experiments for the same nucleus and to
choose the most reliable one.Comment: 14 pages, 4 figures, 2 table
Balling and granulation kinetics revisited
Balling of finely comminuted solids by random coalescence and granulation of iron ore fines and other minerals by autolayering are two major size enlargement processes. The existing kinetic model for random coalescence does not take into account the strong dependence of coordination number on the size distribution of agglomerating entities. We present a coordination number based coalescence model, which mimics the underlying physical process more realistically. Simulations show that in spite of highly diverse model structures, random and coordination coalescence models give remarkably similar results. Only static models of autolayering are available presently. These map the input size distribution of feed solids into steady state or terminal size distribution of granules, with little or no information on the path traversed by the process. We propose a continuous-time dynamic model of autolayering within the population balance framework. The model, which is based on the proportionate growth postulate of autolayering, agrees reasonably well with experimental data
Barriers to Changing Dietary Behavior
Abstract
Dietary change requires giving up long established patterns of eating behavior and acquiring new habits. ‘Noncompliance’
to diet advice may be a result of inability to provide diet self-management training and getting the
right messages across to change eating behavior. Using a pre-tested questionnaire based interview, we carried out a
study amongst 350 adults (> 20 years) with type 2 diabetes from two metro cities in South India, who had previously
received diet advice with the objective to understand perceptions, attitudes and practices, as well as study factors
that enhance or reduce compliance to diet advice. Ninety six patients (28%) followed diet for the full duration of
diabetes (Group1), 131 (38%) followed diet for a partial duration varying between more than a quarter to three
quarters of the total diabetes duration (Group 2) and 115 (34%) did not follow diet advice (Group 3) – followed for
a duration less than a quarter of their diabetes duration.
Study results show that many factors both patient and health care provider related influence outcomes of dietary
advice. Factors that have a positive impact on compliance are – older age, shorter duration, nuclear family, good
family support, less busy work life, higher health consciousness, advice given by dietician, more frequent visits to
dietician, advice that includes elements to promote overall health not merely control of blood sugar, diet counseling
that is easy to understand and use and includes healthy food options, cooking methods, practical guidance to
deal with lifestyle issues. We conclude that patient barriers related to life circumstance are mostly non-modifiable,
most modifiable barriers are related to behavioural aspect and the inability of the health care provider to provide
individualized diet advice and self management training. Efforts must be made to improve counseling skills
A duplicated spinous process of the C7 vertebra
Normally the 7th cervical vertebra (C7) has a long non-bifid spine. A bifid spine
is a feature of typical cervical vertebrae such as C3–C6. In contrast to past
studies, which have described a bifid spine in the C3–C6 cervical vertebrae,
this study is a report on the presence of a duplicated spinous process in the C7
vertebra with an intervening space. The presence of such anomalies may be
associated with other congenital anomalies and needs a careful and thorough
clinical approach. This is an extremely rare finding which may be of clinical interest
to radiologists, neurologists, orthopaedic surgeons, anthropologists and
forensic personnel. The present case report describes the anatomical details in
the bone specimen along with its radiological picture in a case of a duplicated
spinous process of the C7 vertebra
A triplicate obturator foramen
The obturator foramen is a large opening in the hip bone situated below and
anterior to the acetabulum. The obturator foramen is enclosed by the obturator
membrane, apart from the part above near the obturator groove, where the
obturator vessels and nerve pass through. The present study reports multiple
openings in the obturator foramen detected incidentally in a left hip bone specimen
and discusses its clinical implications. To the best of our knowledge, the
occurrence of multiple openings associated with the obturator foramen is rare
and has not been reported in any standard textbook of anatomy or in any research
study. Anatomical knowledge of the presence of such anomalies may be
clinically important for radiologists interpreting skiagrams and surgeons performing
operative procedures in the hip region
A Note on the Thermodynamics of the Wet-and Dry-Bulb Hygrometer
The paper deals with the thermodynamic study of the wet-and-dry bulb
hygrometer as applied to other liquids besides water. Hygroscopic liquids are also included.
The theory is found in reasonable accord with experiment
An asymmetrical inferior articular process of a lumbar vertebra
The present case report describes the topographical anatomy and radiological
study of an asymmetrical inferior articular process of a lumbar vertebra, which
was detected during routine osteology teaching of undergraduate medical students.
The inferior articular process of the lumbar vertebra on the left side was
rudimentary, while that on the right was normal in size. On the left side an
additional bony projection was noted anterior to the rudimentary inferior articular
process. The difference in height between the inferior articular processes of
the two sides may play an important role in the kinematics of the particular
joint. The orientation of the facets of the articular processes of the vertebrae are
important for axial weight transmission and anomalies involving these can possibly
alter the orientation of movements in that particular segment. An asymmetrical
inferior articular process may be related to disc prolapse and may be
a cause of back pain. In view of the paucity of research reports of anatomicoradiological
study of the inferior articular process of a lumbar vertebra in relation
to other parts of the vertebra, we, as anatomists, believe that knowledge of
anomalies of the inferior articular process may be relevant for academic, anthropological
and clinical purposes
- …