Fusion cross section data for
9
Be
projectile on
169
Tm
,
181
Ta
,
187
Re
and
197
Au
targets have been analyzed using the Stelson model. The threshold (lowest) barriers obtained from the fit to the ...data have been compared with the ones calculated starting from the projectile/target neutron separation energy (
S
n
) values. The respective direct reaction cross sections,
viz.
, neutron transfer, non-capture breakup and incomplete fusion have been added to the corresponding fusion cross sections, to obtain the reaction cross sections for the above systems. The Stelson model cross section expression has also been used to fit the reaction cross section data. It has been found that while the threshold barrier for fusion is related to the
S
n
of the target, the corresponding barrier from the reaction data is connected to the
S
n
(breakup energy) of the projectile.
We describe the physics and data included in the Reference Input Parameter Library, which is devoted to input parameters needed in calculations of nuclear reactions and nuclear data evaluations. ...Advanced modelling codes require substantial numerical input, therefore the International Atomic Energy Agency (IAEA) has worked extensively since 1993 on a library of validated nuclear-model input parameters, referred to as the Reference Input Parameter Library (RIPL). A final RIPL coordinated research project (RIPL-3) was brought to a successful conclusion in December 2008, after 15 years of challenging work carried out through three consecutive IAEA projects. The RIPL-3 library was released in January 2009, and is available on the Web through
http://www-nds.iaea.org/RIPL-3/
. This work and the resulting database are extremely important to theoreticians involved in the development and use of nuclear reaction modelling (ALICE, EMPIRE, GNASH, UNF, TALYS) both for theoretical research and nuclear data evaluations.
The numerical data and computer codes included in RIPL-3 are arranged in seven segments:
MASSES contains ground-state properties of nuclei for about 9000 nuclei, including three theoretical predictions of masses and the evaluated experimental masses of Audi
et al. (2003).
DISCRETE LEVELS contains 117 datasets (one for each element) with all known level schemes, electromagnetic and
γ-ray decay probabilities available from ENSDF in October 2007.
NEUTRON RESONANCES contains average resonance parameters prepared on the basis of the evaluations performed by Ignatyuk and Mughabghab.
OPTICAL MODEL contains 495 sets of phenomenological optical model parameters defined in a wide energy range. When there are insufficient experimental data, the evaluator has to resort to either global parameterizations or microscopic approaches. Radial density distributions to be used as input for microscopic calculations are stored in the MASSES segment.
LEVEL DENSITIES contains phenomenological parameterizations based on the modified Fermi gas and superfluid models and microscopic calculations which are based on a realistic microscopic single-particle level scheme. Partial level densities formulae are also recommended. All tabulated total level densities are consistent with both the recommended average neutron resonance parameters and discrete levels.
GAMMA contains parameters that quantify giant resonances, experimental gamma-ray strength functions and methods for calculating gamma emission in statistical model codes. The experimental GDR parameters are represented by Lorentzian fits to the photo-absorption cross sections for 102 nuclides ranging from
51V to
239Pu.
FISSION includes global prescriptions for fission barriers and nuclear level densities at fission saddle points based on microscopic HFB calculations constrained by experimental fission cross sections.
Experimental and theoretical perspectives of reactive extraction of gallic acid (GA) from aqueous solutions using tri‐n‐butyl phosphate (TBP) and tri‐n‐octylamine (TOA) as extractant dissolved in ...three nontoxic natural oils, namely, rice bran oil, sunflower oil, and soybean oil, are investigated. The solvent's extractability is observed in an order of sunflower oil > rice bran oil > soybean oil and rice bran oil > sunflower oil > soybean oil with TOA and TBP, respectively. The theoretical insights of reaction mechanisms for the extraction of GA are estimated in the form of overall equilibrium constants (KE), stoichiometric coefficients (m), individual equilibrium constants (K11, K12, K21), and concentrations (C11, C12, and C21) of various complexes formed between extractant and acid.
Gallic acid (GA) from aqueous streams was extracted by reactive extraction with organic phase combinations of tributylphosphate and trioctylamine with rice bran oil, sunflower oil, and soybean oil. An equilibrium study was done for GA distribution in aqueous and organic phases. From the biocompatibility and economic point of view, the natural oils as nontoxic diluents are much favorable for GA recovery.
Polymorphs enable us to gain molecular insights into the compaction behavior of pharmaceutical powders. Two polymorphs (α and γ) of indomethacin (IMC) were investigated for in-die and out-of-die ...compaction behavior using compressibility, tabletability and compactibility (CTC) profile, stress–strain relationship, and Heckel, Kawakita and Walker equations. Compaction studies were performed on a fully instrumented rotary tabletting machine. CTC analysis revealed that the γ-form has increased compressibility while the α-form showed greater compactibility. The α-form also showed increased tabletability over the γ-form at all the compaction pressures. Lower values of Py (Heckel parameter) and 1/b (Kawakita parameter) indicated increased deformation behavior of γ-form. Stress–strain analysis also supports the increased compressibility of γ-form. In addition, Walker analysis showed higher compressibility coefficient (W) for α-form, consistent with its greater tabletability. Thus, tabletability of IMC polymorphs was governed by the compactibility of the material. Detailed examination of crystallographic data revealed that the presence of a slip plane system in the γ-form offered it increased compressibility and deformation behavior. However, the α-form showed greater compactibility by virtue of closer molecular packing (higher true density). Hence, although direct correlation between tabletability and the presence of slip planes in the crystals has been reported, prediction solely based on this crystallographic feature must be avoided. The present work reiterates the influence of the crystal packing on the tabletability of the pharmaceutical polymorphs.
The present work investigates the mechanical behaviour of an aspirin-paracetamol (ASP-PCM) eutectic mixture (EM). A EM of ASP-PCM was prepared using a solvent evaporation method. Differential ...scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) confirmed the eutectic formation with a composition of 53 : 47% w/w (ASP : PCM). The compaction behaviour of the EM and a physical mixture (PM) of ASP and PCM was compared using a fully instrumented rotary tablet press equipped with a Portable Press Analyzer™ (PPA). The obtained data were compared using compressibility, tabletability and compactibility profiles and Heckel analysis. The EM exhibited higher compressibility, tabletability and plastic deformation compared to the PM. Heckel analysis showed that the mean yield pressure,
P
y
, was lower for the EM (46.9 MPa) than the PM (222.8 MPa), thus confirming the better plastic deformation of the EM. The better deformation behaviour of the EM was attributed to its layered microstructure. The sliding of adjacent layers over each other under an applied compaction pressure offered higher plastic deformation and thus provided a greater interparticulate bonding area in the EM compared to the PM. However, there was no significant difference in the compactibility profiles indicating a similar interparticulate bonding strength of the two powders. Thus, the EM showed better tabletability compared to the PM by virtue of its greater compressibility and plastic deformation.
The present work investigates the mechanical behaviour of an aspirin-paracetamol (ASP-PCM) eutectic mixture (EM).
Assembly consisting of cast and wrought aluminum alloys has wide spread application in defense and aero space industries. For the efficacious use of the transition joints, the weld should have ...adequate strength and formability. In the present investigation, A356 and 6061 aluminum alloys were friction stir welded under tool rotational speed of 1000–1400
rpm and traversing speed of 80–240
mm/min, keeping other parameters same. The variable process window is responsible for the change in total heat input and cooling rate during welding. Structural characterization of the bonded assemblies exhibits recovery-recrystallization in the stirring zone and breaking of coarse eutectic network of Al–Si. Dispersion of fine Si rich particles, refinement of 6061 grain size, low residual stress level and high defect density within weld nugget contribute towards the improvement in bond strength. Lower will be the tool rotational and traversing speed, more dominant will be the above phenomena. Therefore, the joint fabricated using lowest tool traversing and rotational speed, exhibits substantial improvement in bond strength (∼98% of that of 6061 alloy), which is also maximum with respect to others.
Polymorphism plays a critical role during pharmaceutical development, as it helps in the selection of optimal solid form. In present study, mechanical properties of ranitidine hydrochloride ...polymorphs were studied using instrumented tablet press, to understand the effect of crystal packing on the compaction behaviour. Out-of-die compressibility plot and Heckel analysis confirmed greater plastic deformation of form II over form I. Detailed crystallographic examination revealed that form I has several weak C-H O interactions across the 'proposed slip plane' parallel to (−2 0 2) that prevent slip under compaction pressure. On the other hand, crystal structure of form II was relatively more open and multiple slip were possible under compaction pressure. These crystallographic features offered increased compressibility and deformability to form II. In absence of an active slip plane system, closed crystal structure of form I resists deformation under compaction pressure and hence showed poor compressibility and higher mean yield pressure. However, form I showed greater tabletability at a given compaction pressure, by virtue of its greater bonding strength.
The mechanical properties of ranitidine hydrochloride polymorphs have been studied using instrumented tablet press, to understand the effect of crystal packing on the compaction behaviour.
.
Nuclear physics research is growing on several fronts, along energy and intensity frontiers, with exotic projectiles and targets. The nuclear physics facilities under construction and those being ...planned for the future make the prospects for research in this field very bright.
Excitation functions of the Zn(p,xn)Ga reactions Hemalatha, M.; Patel, A.; Kailas, S.
Applied radiation and isotopes,
February 2020, 2020-Feb, 2020-02-00, 20200201, Letnik:
156
Journal Article
Recenzirano
The excitation functions for 64,66,67,68,70Zn(p,n)64,66,67,68,70Ga and 64,66,67,68,70Zn(p,2n)63,65,66,67,69Ga have been calculated for incident proton energies from threshold values to 30 MeV using ...the statistical model code TALYS-1.6. The (p,n) and (p,2n) cross sections have been calculated using both phenomenological Koning and Delaroche (KD) and semimicroscopic Jeukenne-Lejeune-Mahaux-Bruyeres (JLMB) optical model potentials. The phenomenological back-shifted Fermi gas model (BFM) and microscopic Hartree-Fock (HF) approaches for calculation of level densities have been compared in the present work. The pre-equilibrium process has been treated using exciton model. The sensitivity of cross section data to different models of optical model potential and level density have been investigated. It is found that the (p,n) and (p,2n) cross section calculations with semimicroscopic JLMB optical model potential and microscopic HF level density show agreement with the data. The (p,n) and (p,2n) cross section calculations have been compared with corresponding cross sections from nuclear data library, TENDL-2019. The (p,xn) cross sections obtained will be useful in several applications, particularly, for optimization of production routes for Ga isotopes.
•Calculated excitation functions for (p,n) and (p,2n) reactions on stable Zn isotopes.•Production cross sections of 63,64,65,66,67,68,69,70Ga isotopes.•Microscopic and phenomenological calculations of optical potential and level density.•Explanation of data even using an essentially parameter free microscopic approach.
