Limited studies have compared BIM’s impacts on project performance via business types, working experience, and locations. A survey was conducted results found that (1) BIM helped with the early detection of design errors (R1), pre-construction RFIs (R2), number repeat customers (R12), but negatively affected other 9 indicators (R3~R11); (2) for R1/R2/R12, contractors, international projects, st...

Oneand two-body densities in position space have been calculated for the atomic beryllium isoelectronic series starting from explicitly correlated multideterminant wave functions. The effects of electronic correlations have been systematically studied by comparing the correlated results with the corresponding Hartree–Fock ones. Some expectation values such as ^d(r)&, ^r& , ^d(r12)& , ^r12 n &, ...

Two new problems of bivalent propositional logic are proposed here: firstly, to distinguish the sense of propositions, besides the logical value and secondly, to analyze the ”ponderal” difference between two parts of a proposition: subject-predicate. 1 Relational projections and extensions Let r = (A1, A2, A3, R) be a ternary relation (see [3]). Starting with this, we may define three binary re...

We study a simple, BCS like, model which describes unconventional superconductivity on the basis of an electronelectron attraction corresponding to the delta-shell potential: U(r12) = −gδ(r12 − r0). It predicts a Tc vs. doping behavior similar to that characteristic of the High Tc cuprates.

In 1985 Kutzelnigg showed that a large percentage of the electron correlation energy for helium can be recovered using a single explicitly correlated basis function, chosen to fit the cusp at the correlation hole. In particular the simple wave functionW 1⁄4 ð1þ 2 r12ÞU returned more than 80% of the correlation energy. In this paper we return to Kutzelnigg’s simple ansatz and remove the conventi...

We present an efficient algorithm for evaluating a class of two-electron integrals of the form r12⊗r12/r12(n) over one-electron Gaussian basis functions. The full Breit interaction in four-component relativistic theories beyond the Gaunt term is such an operator with n = 3. Another example is the direct spin-spin coupling term in the quasi-relativistic Breit-Pauli Hamiltonian (n = 5). These int...

refrigerants that are used in refrigeration systems, cause environmental difficulties such as depletion of ozone layer and greenhouse effect. thus, we must find substitutes for such refrigerants, in this paper, the effect of refrigerant on the thermodynamics performance of refrigeration cycles are studied. to do this, a refrigerator that has designed for r12, is simulated. results show that pur...

Electron correlation has wide applications in various domains of physics. In the past decade, a variety of methods have been proposed to obtain accurate eigenvalues and eigenfunctions of the ground states. These variational methods can be divided into two categories according to whether their trial basis functions depend explicitly on the inter-electron separation r12 or not. The methods employ...