Simultaneous measurements of indoor radon and thoron and inhalation dose assessment in Douala City,Cameroon

ABSTRACT

Radon, thoron and associated progeny measurements have been carried out in 71 dwellings of Douala city, Cameroon. The radon–thoron discriminative detectors (RADUET) were used to estimate the radon and thoron concentration, while thoron progeny monitors measured equilibrium equivalent thoron concentration (EETC). Radon, thoron and thoron progeny concentrations vary from 31?±?1 to 436?±?12 Bq?m^–3, 4?±?7 to 246?±?5 Bq?m^–3, and 1.5?±?0.9 to 13.1?±?9.4 Bq?m^–3. The mean value of the equilibrium factor for thoron is estimated at 0.11?±?0.16. The annual effective dose due to exposure to indoor radon and progeny ranges from 0.6 to 9?mSv?a^–1 with an average value of 2.6?±?0.1?mSv?a^–1. The effective dose due to the exposure to thoron and progeny vary from 0.3 to 2.9?mSv?a^–1 with an average value of 1.0?±?0.4?mSv?a^–1. The contribution of thoron and its progeny to the total inhalation dose ranges from 7 to 60?% with an average value of 26?%; thus their contributions should not be neglected in the inhalation dose assessment.     

Understanding quantum entanglement by thermo field dynamics

We propose a new method to understand quantum entanglement using the thermo field dynamics (TFD) described by a double Hilbert space. The entanglement states show a quantum-mechanically complicated behavior. Our new method using TFD makes it easy to understand the entanglement states, because the states in the tilde space in TFD play a role of tracer of the initial states. For our new treatment, we define an extended density matrix on the double Hilbert space. From this study, we make a general formulation of this extended density matrix and examine some simple cases using this formulation. Consequently, we have found that we can distinguish intrinsic quantum entanglement from the thermal fluctuations included in the definition of the ordinary quantum entanglement at finite temperatures. Through the above examination, our method using TFD can be applied not only to equilibrium states but also to non-equilibrium states. This is shown using some simple finite systems in the present paper.     

Effects of pressure and temperature on the solubility of monosodium L-glutamate monohydrate in water

Abstract

The solubility of monosodium L-glutamate monohydrate (MSG.H₂O) in water was measured at pressures in the range of 0.10-300MPa and 298.15K. The density of MSG solution at high concentrations and heat of solution at saturated concentration were also measured at atmospheric pressure. The solubility, m_s, increased with increasing pressure and the pressure coefficient, Θ_p, [?(? In m_s,? p)_T] at 0.10 MPa was (2.0 ± 0.1) × 10-¹⁰Pa-1. It agrees well with (2.1 ±0.2)× 10-¹⁰ Pa-¹ thermodynamically estimated using the partial molar volume, the activity coefficient of the solute in solution, and the molar volume of the crystal. The excellent agreement at 0.10MPa gives us confidence in the solubility data at higher pressures. The heat of solution data and other pertinent values were used to calculate the temperature coefficient of solubility, Θ_T [? (? In m_s/?(1/T))_p], by a thermodynamic equality. The resulting Θ_T compares well with the data directly measured by Ogawa.     

Effect of high pressure treatment on sarcoplasmic reticulum

Abstract

This paper describes the changes in biochemical activities of sarcoplasmic reticulum(SR) and Ca²⁺ release from SR in the rabbit skeletal muscle subjected to a high pressure treatment(100∽300 MPa) to investigate the mechanism for pressure-induced meat tenderization and acceleration of meat conditioning. Pressure-dependent changes were observed in the both extra and basal ATPase activities of SR prepared from the muscles exposed to high pressure. Ca²⁺ uptaking ability of SR vesicles measured by fluorescent chelating reagent, indo-1, decreased with increasing pressure applied to the muscle. Ultrastructural studies revealed that Ca²⁺ which was mainly localized in the SR region of the untreated fiber bundles was translocated into myofibrils in the pressurized muscle. Obtained results in this report may be one of the causes for meat tenderization and acceleration of meat conditioning induced by high pressure treatment.     

Uniform estimates and uniqueness of stationary solutions to the drift–diffusion model for semiconductors

We study the stationary problem of the drift–diffusion model with a mixed boundary condition. For this problem, the existence of solutions was established in general settings, while the uniqueness was investigated only in some special cases which do not entirely cover situations that semiconductor devices are used in integrated circuits. In this paper, we prove the uniqueness in a physically relevant situation. The key to the proof is to derive two-sided uniform estimates for the densities of the electron and hole. We establish a new technique to show the lower bound. This together with the Moser iteration method leads to the upper bound.     

Isometries of some F-algebras of holomorphic functions on the upper half plane

Linear isometries of N ^p (D) onto N ^p (D) are described, where N ^p (D), p > 1, is the set of all holomorphic functions f on the upper half plane D = {z ∈ ?: Im z > 0} such that sup _y >0 ∫_? ln ^p (1 + |(x + iy)|) dx < +∞. Our result is an improvement of the results by D.A. Efimov.     

Positive solution to semilinear parabolic equation associated with critical Sobolev exponent

We study the semilinear parabolic equation ${u_{t}- \Delta u = u^{p}, u \geq 0}$ on the whole space R ^N , ${N \geq 3}$ associated with the critical Sobolev exponent p = (N + 2)/(N ? 2). Similarly to the bounded domain case, there is threshold blowup modulus concerning the blowup in finite time. Furthermore, global in time behavior of the threshold solution is prescribed in connection with the energy level, blowup rate, and symmetry.     

Some constraint qualifications for quasiconvex vector-valued systems

In this paper, we consider minimization problems with a quasiconvex vector-valued inequality constraint. We propose two constraint qualifications, the closed cone constraint qualification for vector-valued quasiconvex programming (the VQ-CCCQ) and the basic constraint qualification for vector-valued quasiconvex programming (the VQ-BCQ). Based on previous results by Benoist et al. (Proc Am Math Soc 13:1109–1113, 2002), and Suzuki and Kuroiwa (J Optim Theory Appl 149:554–563, 2011), and (Nonlinear Anal 74:1279–1285, 2011), we show that the VQ-CCCQ (resp. the VQ-BCQ) is the weakest constraint qualification for Lagrangian-type strong (resp. min–max) duality. As consequences of the main results, we study semi-definite quasiconvex programming problems in our scheme, and we observe the weakest constraint qualifications for Lagrangian-type strong and min–max dualities. Finally, we summarize the characterizations of the weakest constraint qualifications for convex and quasiconvex programming.     

Construction of isostructural hydrogen-bonded organic frameworks: limitations and possibilities of pore expansion

The library of isostructural porous frameworks enables a systematic survey to optimize the structure and functionality of porous materials. In contrary to metal–organic frameworks (MOFs) and covalent organic frameworks (COFs), a handful of isostructural frameworks have been reported for hydrogen-bonded organic frameworks (HOFs) due to the weakness of the bonds. Herein, we provide a rule-of-thumb to develop isostructural HOFs, where we demonstrate the construction of the third and fourth generation of isostructural HAT-based HOFs (TolHAT-1 and ThiaHAT-1) by considering three important structural factors, that are (1) directional H-bonding, (2) shape-fitted docking of the HAT core, and (3) modulation of peripheral moieties. Their structural and photo-physical properties including HCl vapor detection are presented. Moreover, TolHAT-1, ThiaHAT-1, and other isostructural HOFs (CPHAT-1 and CBPHAT-1) were thoroughly compared from the viewpoints of structures and properties. Importantly, molecular dynamics (MD) simulation proves to be rationally capable of evaluating the stability of isostructural HOFs. These results can accelerate the development of various isostructural molecular porous materials.

The library of isostructural porous frameworks enables a systematic survey to optimize the structure and functionality of porous materials.     

Lattice wave emission from moving cracks

Antiplane shear cracks moving in square lattices have been studied in a molecular dynamics simulation. They become unstable when a critical stress intensity at the tip is reached. Within picoseconds they accelerate to steady state velocity, which can be supersonic or not, depending on the interatomic potential. If the surface energy is low, they become supersonic; if the surface energy is high, they reach only subsonic speeds before the crystal reaches the theoretical shear strength. A simple modification of the interatomic potential switches the crystal behaviour from brittle to ductile, substituting dislocations to daughter cracks. The steady state velocities are the same, whether the model crystal is brittle or ductile. The steady state velocity is a function of the applied stress, not the stress intensity.