An ion beam has quite different vacuum requirements in different sections of an accelerator. Behind a stripper gas or after interaction with a gas target the vacuum conditions are poor, whereas in an accelerator module or especially in a storage ring the residual gas pressure has to be orders of magnitude better. As a new device to allow an ion beam to enter sections of different pressure we in...

An overview of some issues discussed is given, including the following ones: (i) the mechanism of confinement, (ii) the structure of the string, (iii) nonperturbative glue in vacuum and hadrons, and (v) quark-hadron duality. In doing so I try to indicate issues important for JLab. Finally I discuss another issue debated during this conference, namely (vi) whether one can use some common effecti...

We use the SU(3) x SU(2) x U(1) renormalization group equations to constrain fermion masses and charged-scalar couplings in two-Higgs grand unified theories. We find upper bounds on the sum of all quark (or lepton) masses and show that the Cabibbo mixings of heavy quarks tend to be small. We bound the vacuum expectation values of the Higgs fields, and use these limits to place strong restrictio...

The theory of direct electron-positron pair production in the collision of heavy ions i s formulated in the framework of the quasimolecular model. The pair production process acquires a collective nature for (Z1 +Z,)cu; 1 and can be understood a s the shakeoff of the strong vacuum polarization cloud formed in the quasimolecule. The total Cross section is, e .g., 76 l b for Pb + Pb at Coulomb ba...

New results at four-loop order in perturbative QCD for the first two Taylor coefficients of the heavy quark vacuum polarization function are presented. They can be used to perform a precise determination of the charmand bottom-quark mass. Implications for the value of the quark masses are briefly discussed. PACS. 12.38.Bx Perturbative calculations – 12.38.-t Quantum chromodynamics – 11.55.Fv Di...

Exploiting the analyticity of the vacuum polarization function Π(q) around q = 0 and using dispersion relations, the derivatives at q = 0 can be expressed as weighted integrals over the imaginary part of Π(q), which in turn is given by the cross section for electronpositron annihilation into hadrons. Let us denote the normalised cross section for heavy quark production as RQ(s) ≡ σQ(s)/σpoint(s...

We discuss the stability of vacua in two-dimensional gauge theory for any simple, simply connected gauge group. Making use of the representation of a vacuum in terms of a Wilson line at infinity, we determine which vacua are stable against pair production of heavy matter in the adjoint of the gauge group. By calculating correlators of Wilson loops, we reduce the problem to a problem in represen...

Objective: The main objective pursued in this paper is to investigate the energy consumption for drying of potato slices using vacuum-infrared drying method. Methods: Drying of potato slices with the thicknesses of 1, 2 and 3 mm were conducted at vacuum levels of zero (without vacuum), 20, 80 and 140 mm [Hg], infrared radiation at power levels of 100, 150 and 200 W in the three repetition. Resu...

Objective: The main objective pursued in this paper is to investigate the energy consumption for drying of potato slices using vacuum-infrared drying method. Methods: Drying of potato slices with the thicknesses of 1, 2 and 3 mm were conducted at vacuum levels of zero (without vacuum), 20, 80 and 140 mm [Hg], infrared radiation at power levels of 100, 150 and 200 W in the three repetition. Resu...