Direct application of UNIFAC activity coefficient computer programs to the calculation of solvent activities and .chi.-parameters for polymer solutions

Application of UNIFAC computer calculations to polymer solutions does not seem to make sense because of the value of the solvent activity: close to 1.000 over a considerable range of concentrations (up to 90% of polymer). A simple procedure is proposed to calculate solvent activity coefficients, and thus X-parameters, such that the easily available UNIFAC computer programs may be applied directly, without any modification

Quantum simulation of classical thermal states

We establish a connection between ground states of local quantum Hamiltonians and thermal states of classical spin systems. For any discrete classical statistical mechanical model in any spatial dimension, we find an associated quantum state such that the reduced density operator behaves as the thermal state of the classical system. We show that all these quantum states are unique ground states of a universal 5-body local quantum Hamiltonian acting on a (polynomially enlarged) system of qubits arranged on a 2D lattice. The only free parameters of the quantum Hamiltonian are coupling strengthes of two-body interactions, which allow one to choose the type and dimension of the classical model as well as the interaction strength and temperature.Comment: 4 pages, 1 figur

Nodal integration of meshless methods

Meshless methods offer interesting properties for the simulation of bulk forming\ud processes. This research concerns the investigation of the stabilized conforming nodal integration scheme (SCNI) for use in metal-forming processes. Two tests are carried out. Firstly, the performance of SCNI is compared to a standard integration scheme. The performance seems problem specific. Secondly the footing of a piece of nearly incompressible material is used for testing the locking behavior of the method. No volumetric locking was found

Adaptive smoothed FEM for forming simulations

FEMsimulation of large deformations as occur in metal forming processes is usually accompanied with highly distorted meshes. This leads first to a reduction of accuracy and later to loss of convergence when implicit solvers are used. Remeshing can be used to reduce element distortion, but repeated remeshing will result in smoothing of data like equivalent plastic strain, due to averaging and interpolation. A meshless method circumvents the problem of mesh distortion, but depending on the integration of the weak formulation of equilibrium mapping of data and hence smoothing of data still remains unless a\ud nodal integration scheme is used. Starting with a LocalMaximum Entropy approach [1] with nodal integration, we end-up with a smoothed Finite Element formulation in the limit of local approximations [2]. It is straightforward to adapt the triangulation in every increment, yielding an Adaptive Smoothed Finite\ud Element Method, in which large deformations can be modelled with a Lagrangian description without the necessity to map data from one step to the other.\ud A cell based stabilized conforming nodal integration method (SCNI) [3] is used. Depending on the configuration of nodes, nodal integration can yield singular stiffness matrices, resulting in spurious displacement modes [4]. A stabilization is used, based on minimizing the difference between a ‘linear\ud assumed’ and the consistent strain field. The cells are based on the Delaunay triangulation, connecting mid-sides and centres of gravity of the triangles (Figure 1). Especially at the outer boundary, this yields a simpler formulation than using the dual Voronoi tesselatio

On the complexity of the economic lot-sizing problem with remanufacturing options

In this paper we investigate the complexity of the economiclot-sizing problem with remanufacturing (ELSR) options. Whereas inthe classical economic lot-sizing problem demand can only besatisfied by production, in the ELSR problem demand can also besatisfied by remanufacturing returned items. Although the ELSRproblem can be solved efficiently for some special cases, we showthat the problem is NP-hard in general, even under stationary costparameters.remanufacturing;complexity;lot-sizing

Embedded 5V-to-3.3V Voltage Regulator for Supplying Digital ICs in 3.3V CMOS Technology

A fully integrated 5 V-to-3.3 V supply voltage regulator for application in digital IC's has been designed in a 3.3 V 0.5 μm CMOS process. The regulator is able to deliver peak current transients of 300 mA, while the output voltage remains within a margin of 10% around the nominal value. The circuit draw's a static quiescent current of 750 μA during normal operation, and includes a power-down mode with only 10 μA current consumption. The die area is 1 mm2, and can be scaled proportional to the maximum peak current. Special precautions have been taken to allow 5 V in the 3.3 V process

Power analysis on smartcard algorithms using simulation

This paper presents the results from a power analysis of the AES and RSA algorithms by\ud simulation using the PINPAS tool. The PINPAS tool is capable of simulating the power\ud consumption of assembler programs implemented in, amongst others, Hitachi H8/300\ud assembler. The Hitachi H8/300 is a popular CPU for smartcards. Using the PINPAS tool, the\ud vulnerability for power analysis attacks of straightforward AES and RSA implementations is\ud examined. In case a vulnerability is found countermeasures are added to the implementation\ud that attempt to counter power analysis attacks. After these modifications the analysis is\ud performed again and the new results are compared to the original results

The Failure of Local and Federal Prosecutors to Curb Police Brutality

Although police departments across the country have attempted to ameliorate the hostility between police officers and the cumminity, through careful screening of applicants, minority recruitment, and community policing, police brutality remains a problem within our urban cities. This Essay will first argue that police brutality is largely ignored. Second, it will examine the obstacles facing local and federal prosecutors in obtaining convictions. Then it will compare the advantages and disadvantages of delegating primary responsibility for these cases to the state versus the federal level. Finally, it will argue that, although there are obstacles and advantages for both local and federal prosecutors, ultimately justice is best seved when police brutality is primarily pursued by local prosecutors