Fission-fragment energy correlation measurements for (nth, f) of 232U and 233U

Fission-fragment mass and kinetic energy distributions and their correlations have been measured for ²³²U and ²³³U. The results on these uranium isotopes and ²³⁵U are compared. The mass peak/valley ratio of 785 ± 68 for ²³²U is the highest of the three isotopes. The 〈E_K〉(μ_H) distributions show significant differences. The dip ΔE_K at symmetry is $\text{16.2 ± 1.0}\text{MeV}\text{(}{}^{232}\text{U}\text{)}$, $\text{17.0 ± 1.0}\text{MeV}\text{(}{}^{233}\text{U}\text{)}\text{and}\text{20.6 ± 1.1}\text{MeV}\text{(}{}^{235}\text{U}\text{)}$. In the yields for high-kinetic-energy-selected events, the mass 134 dominates for ²³³U and ²³⁵U, but for ²³²U it is μ_H≈144, which dominates. This complete reversal of profiles can be understood in terms of fragment shells.     

Vibrational analysis of the products from thermal decomposition of OCS and CO2

The thermal decomposition of CO₂ and OCS has been studied using a shock tube and cw CO probe laser. The energies of activation are in good agreement with the values of other workers. It has been shown that the CO formed from OCS has an initial non-thermal vibrational distribution with a large excess in ν = 0.     

Fission-fragment energy correlation measurements for 252Cf(sf) and structures in far-out asymmetric fission

Fragment-mass and kinetic-energy distribution measurements for ²⁵²Cf(sf) have been extended to the far-out asymmetric low-yield fission region of M_H = 190 compared with the existing data that go up to M_H ≈ 168. The mass yield Y(m) shows a shoulder for M_H ≈ 163 and an important enhancement for M_H ? 176. The 〈E_K〉(m), σ_EK(m) and, to a lesser extent, Y(m) distributions show strong and correlated amplitude fluctuations for M_H ? 170. These data indicate strong and rapid changes in deformation of the nascent fragments and the coexistence of more than one deformed-shell stabilized scission configuration for the same mass splits. These structures and those present in the relatively high-yield regions are discussed in terms of the static macro-microscopic potential-energy calculations.     

Intuitionistic fuzzy semiprime ideals in ordered semigroups

We give characterizations of different classes of ordered semigroups by using intuitionistic fuzzy ideals. We prove that an ordered semigroup is regular if and only if every intuitionistic fuzzy left (respectively, right) ideal of S is idempotent. We also prove that an ordered semigroup S is intraregular if and only if every intuitionistic fuzzy two-sided ideal of S is idempotent. We give further characterizations of regular and intra-regular ordered semigroups in terms of intuitionistic fuzzy left (respectively, right) ideals. In conclusion of this paper we prove that an ordered semigroup S is left weakly regular if and only if every intuitionistic fuzzy left ideal of S is idempotent.     

Fitting the three-parameter Weibull distribution with Cross Entropy

The Weibull distribution is widely used in applications such as reliability and lifetime studies. Although this distribution has three parameters, for simplicity, literature pertaining to Weibull parameter estimation relaxes one of its parameters in order to estimate the other two. When the three-parameter Weibull distribution is of interest, the estimation procedure is complicated. For example, the likelihood function for a three-parameter Weibull distribution is hard to maximize. In this paper, a Cross Entropy (CE) method is developed in the context of maximum likelihood estimation (MLE) of a three-parameter Weibull distribution. Performing a simulation study, a comparative analysis between the newly developed method and two existing methods is conducted. The results show the proposed method has better performance in terms of accuracy, precision and run time for different parameter settings and sample sizes.     

On Gauss-Type Quadrature Rules

Some Gauss-type Quadrature rules over [0, 1], which involve values and/or the derivative of the integrand at 0 and/or 1, are investigated. Our work is based on the orthogonal polynomials with respect to linear weight function ω(t): = 1 ? t over [0, 1]. These polynomials are also linked with a class of recently developed “identity-type functions”. Along the lines of Golub's work, the nodes and weights of the quadrature rules are computed from Jacobi-type matrices with simple rational entries. Computational procedures for the derived rules are tested on different integrands. The proposed methods have some advantage over the respective Gauss-type rules with respect to the Gauss weight function ω(t): = 1 over [0, 1].     

Determining the feasibility of H2O2 production at a graphite cathode using bond dissociation energy: comparing simple and nitrogen doped cathodes

Research on Chemical Intermediates - Hydrogen peroxide (H2O2) is commercially produced by catalytic oxidation of anthrahydroquinone, which is energy-intensive. Electrochemical production of...     

Designing of energetic miktoarm A2B2 star‐shaped polymer by means of click chemistry and ROP techniques

Novel A₂B₂‐type energetic miktoarm star‐shaped copolymers composed of two PGN arms and two PCL arms was synthesized by the combination of ring‐opening polymerization (ROP) and “click” chemistry. Initially, diazido end‐functionalized two‐arm PGN, (PGN)₂‐(N₃)₂, was synthesized by ROP of glycidyl nitrate monomers. Subsequently, (PGN)₂‐(PCL)₂ was obtained from the click reaction between diazido end‐functionalized (PGN)₂‐(N₃)₂ polymers and propargyl‐terminated poly(ε‐caprolactone) (PTPCL). This star copolymer solves problems of PCL (lake of energy) and PGN (low T_g). The Fourier‐transform infrared (FT‐IR), ¹H nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC) studies revealed that (PGN)₂‐(PCL)₂ was successfully obtained. The thermal behavior of star polymer was investigated by thermogravimetric analysis (TGA) and derivative thermogravimetry. The results show that (PGN)₂‐(PCL)₂ decomposed at two stages. The first stage is seen at 212.6°C which related to degradation of –ONO₂ group and second stage attributed to degradation of PCL group which is seen at 346.1°C.