Resource allocation in the North Sea demersal fisheries: A goal programming approach

The management of a fishery is a complex task generally involving multiple, often conflicting, objectives. These objectives typically include economic, biological and social goals such as improving the income of fishers, reducing the catch of depleted species and maintaining employment.Multicriteria decision making (MCDM) techniques appear wellsuited to such a management problem, allowing compromises between conflicting objectives to be analysed in a structured framework. In comparison to other fields, such as water resource planning, forestry and agriculture, there have been few applications of MCDM to fisheries.In this paper, a goal programming model of the North Sea demersal fishery is presented. The model is used to demonstrate the potential applicability of this type of approach to the analysis and development of fisheries management plans with multiple objectives. Alternative scenarios are considered for the problem, and tradeoffs between given objectives are also highlighted and discussed.     

Soliton-antisoliton scattering and capture in λφ4 theory

In this work we have investigated the result of collisions of a soliton-antisoliton pair for various incident velocities in λφ⁴ theory through a series of numerical experiments. It is observed for incident velocities less than a critical velocity V_crit that we have two narrow regions in the velocity spectrum where the result of collision is a scattering of particles along with the emission of some radiation. Outside these two narrow windows the incident particles are captured and form resonances. For velocities greater than V_crit scattering is always obtained and it is found that the square of the outcoming velocity is a linear function of the square of the incoming velocity. From the approximate solution found, an effective potential for widely separated solitons is derived.     

Generalized framework for auxiliary extra dimensions

The theory of gravity with an auxiliary extra dimension is known to give the ghost-free cubic completion of the Fierz-Pauli mass term in the decoupling limit. Our work generalizes the boundary condition in the auxiliary dimension that avoids ghosts order-by-order, and to all orders, in the decoupling limit. Furthermore, we extend the formalism to the case of many auxiliary dimensions, and we show that the multi-dimensional extension with the rotationally invariant boundaries of the bulk, is equivalent to the model with a single auxiliary dimension. The above constructions require the appropriate adjustment of the boundary condition, which we discuss in detail. The other possible extension of the original model by the Gauss-Bonnet term is studied as well.     

Numerical study of electroosmotic micromixing of non-Newtonian fluids

Biofluids which exhibit non-Newtonian behavior are widely used in microfluidic devices which involve fluid mixing in microscales. In order to study the effects of shear depending viscosity of non-Newtonian fluids on characteristics of electroosmotic micromixing, a numerical investigation of flow of power-law fluid in a two-dimensional microchannel with nonuniform zeta potential distributions along the channel walls was carried out via finite volume scheme. The simulation results confirmed that the shear depending viscosity has a significant effect on the degree of mixing efficiency. It was shown as the fluid behavior index of power-law fluid, n, decreases, more homogeneous solution can be achieved at the microchannel outlet. Hence, electroosmotic micromixing was found more practical and efficient in microscale mixing of pseudoplastic fluids rather than those Newtonian and dilatant ones. Furthermore, it was found that increase in Reynolds number results in lower mixing efficiency while electroosmotic forces are kept constant.     

Horizon problem remediation via deformed phase space

We investigate the effects of a special kind of dynamical deformation between the momenta of the scalar field of the Brans–Dicke theory and the scale factor of the FRW metric. This special choice of deformation includes linearly a deformation parameter. We trace the deformation footprints in the cosmological equations of motion when the BD coupling parameter goes to infinity. One class of the solutions gives a constant scale factor in the late time that confirms the previous result obtained via another approach in the literature. This effect can be interpreted as a quantum gravity footprint in the coarse grained explanation. The another class of the solutions removes the big bang singularity, and the accelerating expansion region has an infinite temporal range which overcomes the horizon problem. After this epoch, there is a graceful exiting by which the universe enters in the radiation dominated era.     

Monomial ideals with tiny squares and Freiman ideals

Czechoslovak Mathematical Journal - We provide a construction of monomial ideals in R = K[x, y] such that μ(I2) < μ(I), where μ denotes the least number of generators. This...     

The effect of melt flow index, melt flow rate, and particle size on the thermal degradation of commercial high density polyethylene powder

The powder of EX5 grade of high density polyethylene—without any additives—manufactured by Amirkabir petrochemical company was separated by shaker equipment. The separated powder of average diameter ~25, ~62.5, ~87.5, ~112.5, ~137.5, ~175 and the particles >200 μm was tested by a thermogravimetric (TG) analysis instrument in nitrogen atmosphere and heating rates of 10, 20, and 30 °C min^?1. In addition, the separated powders were analyzed by a melt flow index (MFI) instrument, and the viscosity average molecular mass (M _v) of the powders was tested by a viscometer. Kinetic evaluations were performed by Friedman and Kissinger analysis methods and apparent activation energy for the overall degradation of the powders was determined. The effects of molecular mass, MFI, MFR, and particle size on the degradation TG curve, derivative thermogravimetry curve breadth, and activation energy of thermal degradation were considered. The results showed that the M _v of EX5 pipe grade produced by two serial reactors is increased by increasing of the particle size and, MFI is decreased with a little deviation by particle size increasing. The particle size has no obvious effect on the melt flow rate (MFR), and MFR as function of molecular mass distribution does not change very much. The results showed that the powder with bigger particles and higher molecular mass moderately increases the activation energy and shifts the degradation curve to the higher temperatures.     

A CSD analysis on H-bond patterns from phosphoric triamides to their coordination compounds, new complexes with (tBuNH)3PO ligand (PO): Cl2Ph2Sn(PO)2 and Fe(PO)2(NO3)3

The phosphoryl donor ligand (^tBuNH)₃PO (PO) was used for preparation of new tin(IV), Cl₂Ph₂Sn(PO)₂ (1), and iron(III), Fe(PO)₂(NO₃)₃ (2), complexes. These complexes are the first examples of using a phosphoric triamide containing a secondary nitrogen atom, [RNH]₃P(O), for preparation of an organotin(IV) complex of the type ([RNH]₃P(O))₂X₂Ph₂Sn, X = halide, and an iron(III) complex. In 1, the Sn coordination geometry is octahedral with the pair of similar ligands in a trans orientation. The Fe center in 2 is seven-coordinated with the two phosphoramide ligands in a trans fashion, too. This article also reviews the structures of analogous complexes with phosphoric triamide ligands, deposited in the CSD, aiming to classify hydrogen bond patterns in this category of compounds. Moreover, it is tried to find a relationship between the H-bond patterns in complexes and the related free ligands.