Showing papers by "Polytechnic University of Milan published in 1970"
TL;DR: In this paper, general piecewise linear constitutive laws with associated flow rules are formulated in matrix notation and some properties and specializations (in particular to kinematic and isotropic hardening) are discussed.
Abstract: General piecewise linear constitutive laws with associated flow rules are formulated in matrix notation; some properties and specializations (in particular to kinematic and isotropic hardening) are discussed. With reference to finite element models of structures and, hence, in matrix-vector description, the following results are achieved:
a) the holonomic solutions to the analysis problem for given loads and dislocations are shown to be characterized by means of six “quadratic-linear” minimum principles, two of general, four of conditioned validity;b) the incremental counterparts of the above theorems are indicated by analogy; some comparison properties concerning holonomic and nonholonomic solutions, are pointed out;c) a shakedown theorem is established for variable repeated loads and dislocations, with allowance for inertia forces and viscous damping, i. e. a generalization to workhardening structures of Ceradini's and (in quasi-static situations) Melan's theorems;d) a method is proposed for evaluating under holonomy hypothesis, or bounding from above, the safety factor with respect to local failure due to limited plastic strain capacity.
353 citations
TL;DR: In this article, the synthesis of polymers with tertiary amino groups as structural units is discussed. But the synthesis is restricted to polymeric compounds with enamines as monomers, and results of practical interest were obtained by copolymerizing enamines with acrylonitrile.
139 citations
TL;DR: In this article, a general carbonyl olefination scheme taking into account the majority of known reactions of this kind is proposed, and a stable solution of methylene magnesium halide which easily olefinates aldehydes and ketones affording the corresponding methylenic ole fins in good yields.
87 citations
TL;DR: In this article, the incremental boundary value problem for elastoplastic workhardening continua, allowing for distributed dislocations, is discussed both in the traditional terms of continuum mechanics and in matrix notation on the basis of finite element discretization.
Abstract: The paper discusses the incremental boundary value problem for elastoplastic workhardening continua, allowing for distributed dislocations. A pair of “dual” extremum theorems reduces the problem to the optimization of convex quadratic forms subject to linear inequalities and equations: the first theorem takes as variables stress and plastic multiplier rates, the latter velocities and plastic multiplier rates. The conclusions reached are specialized to elastic perfectly plastic (nonhardening) cases. The problem is discussed both in the traditional terms of continuum mechanics and in matrix notation on the basis of finite element discretization, using some quadratic programming concepts. Finally a comparison is made with the classical incremental minimum principles of plasticity (Prager-Hodge, Greenberg), which are deduced from the present theorems in a form generalized to the distributed dislocations.
77 citations
TL;DR: A qualitative study of the influence of the reaction medium on pyrrole oxidation with hydrogen peroxide is reported in this paper, where a simple oxidation product was obtained of which the isolation, structure, and some aspects of the chemical reactivity are reported.
72 citations
TL;DR: In this paper, the incremental boundary-value problem is shown to be amenable to the inequality-constrained minimization of a quadratic functional of the plastic multiplier field, and a weak sufficient condition for uniqueness of solution and overall stability is formulated.
Abstract: E lastoplastic constitutive laws with non-associated flow laws and work-hardening or non-hardening or work-softening behaviour are assumed. The incremental boundary-value problem is shown to be amenable to the inequality-constrained minimization of a quadratic functional of the plastic multiplier field. A weak sufficient condition for uniqueness of solution and overall stability is formulated. Application methods founded on finite-element discretization are indicated for solving threedimensional problems.
54 citations
TL;DR: The requirements for accurate differential linearity measurements of multichannel time sorters are discussed, and it is shown that these measurements can be practically done in reasonable counting times and employing standard laboratory instrumentation.
52 citations
TL;DR: In this article, the radiative lifetime τR and the deexcitation energy, ΔEd, of the lsσg→2pσu transition of the F2 center in LiF in the temperature range between 80°K and 300°K were measured and found to be τR(F2) =29(±07) ns ΔEd=0068 (±0005) eV.
24 citations
TL;DR: In this paper, the stereochemistry of perhydrotriphenylene is discussed and compared with that of inositols, both with regard to the number of isomers and to their chirality.
24 citations
TL;DR: In this paper, the relative reactivities of the above mentioned radicals towards butadiene, acrylonitrile, 2,3-dimethylbutadiene and maleic anhydride are discussed in quantitative terms according to their nucleophilic character.
23 citations
TL;DR: This chapter discusses the development of ALGOL, a simple typeless language which permits functional data structures and coroutines, and its introduction to the COGENT programming system.
Abstract: la. McCARTrtY, J. Recursive functions of symbolic expressions and their computation by machine, Pt. I. Comm. ACM 3, 4 (Apr. 1960), 184-195. lb. , ET AL. LISP 1.5 programmers manual. MIT Press, Cambridge, Mass., 1962. 2. LANDIN, P . J . The next 700 programming languages. Comm. ACM 9, 3 (Mar. 1966), 157-166. 3. EVANS, A. PAL--Alanguage designed for teaching programming linguistics. Proc. ACM 23rd Nat. Conf. 1968, Brandin Systems Press, Princeton, N.J., pp. 395--403. 4. VAN WIJNGAARDEN, A. (Ed.), MAILLOUX, B. J., PECK, J. E. L., AND KOSTER, C. H.A. Report on the algorithmic language ALGOL 68. MR 101, Mathematisch Centrum, Amsterdam, Feb., 1969. 5. CHEATHAM, T. E., JR., FISCHER, A., AND JORRAND, P. On basis for ELF--An extensible language facility. Proc. AFIPS 1968 Fall Joint Comput. Conf., Vol. 33 Pt. 2, MDI Publications, Wayne, Pa., pp. 937-948. 6. BALZER, R. M. Dataless programming. Proc. AFIPS 1967 Fall Joint Comput. Conf. Vol. 31, MDI Publications, Wayne, Pa., pp. 535-544. 7. REYNOLDS, J .C . GEDANKEN--A simple typeless language which permits functional data structures and coroutines. ANL-7621, Argonne Nat. Lab., Argonne, Ill., Sept. 1969. 8. WIRTH, N., AND WEBER, H. EULER--A generalization of ALGOL and its formal definition: Pt. I, Pt. II . Comm. ACM 9, 1 and 2 (Jan., Feb. 1966), 13-25, 89-99. 9. WIRTH, N., AND HOARE, C. A. R. A contribution to the development of ALGOL. Comm. ACM 9, 6 (June 1966), 413-432. 10. FARBER, D. J., GRISWOLD, R. E., AND POLONSKY, L P. The SNOBOL3 programming language. Bell Syst. Tech. J. 45 (July-Aug. 1966), 895--944. 11. KAIN, R. Y. Block structures, indirect addressing, and garbage collection. Comm. ACM lZ, 7 (July 1969), 395-398. 12. BURSTALL, R. M., AND POPPLESTONE, R . J . POP-2 reference manual. In Machine Intelligence g, E. Dale and D. Michie (Eds.), American Elsevier, New York, 1968, pp. 205-246. 13a. DAHL, O. J., AND NYGAARD g . SIMULA--An ALGOLbased simulation language. Comm. ACM 9, 9 (Sept. 1966), 671-678. 13b. , MYrmHAU¢, B., AND NYGAARD, K. SIMULA 67 common base language. Publ. No. S-2, Norwegian Computing Center, Oslo, May 1968. 14. FLOYD, R .W. Nondeterministic algorithms. J. ACM 15, 3 (Oct. 1967), 636-644. 15a. REYNOr,DS, J .C. An introduction to the COGENT programming system. Proc. ACM 20th Natl. Conf., 1965, pp. 422436. 15b. , COGENT programming manual. ANL-7022, Argonne Nat. Lab., Argonne, Ill., Mar. 1965. 16. EARLEY, J. An efficient context-free parsing algorithm. Com. ACM 18:2 (Feb. 1970), 94-102. 17. REYNOLDS, J. C. A set-theoretic approach to the concept of type. Working paper, NATO Conf. on Techniques in Software Engineering, Rome, Oct. 1969. 18a. EVANS, A. Private communication. 18b. MORRIS, J. H. Lambda-calculus models of programming languages. MAC-TR-57, Project MAC, MIT, Cambridge, Mass., Dec. 1968.
TL;DR: The main alterations found in the infected cells were: increased ribosome content, dilation of the perinuclear space, degeneration of mitochondria and chloroplasts, and cytoplasmic vacuolation.
Abstract: The presence of mycoplasma has been demonstrated in the phloem of leaves of white clover (Trifolium repens L.) affected by clover dwarf. Mycoplasma-like bodies were found both in parenchyma and companion cells and in sieve elements.
TL;DR: Poly-allyldiethylamine-N-oxide has in vitro a marked antiheparin activity, analogous to that of protamine; however, it offers the advantage over the latter of a far lower direct anticoagulant action.
TL;DR: In this article, the resolution into antipodes of perhydrotriphenylene (I) (point group D 3 ) through the thermal decomposition of the optically active t-butylperoxi-carbonyl derivative is described.
TL;DR: In this article, the class of quasi-stationary periodic operations is considered and the optimal control is proved to be bang-bang and the number of switching points is found to be bounded by the integral constraints on the control and output variables.
TL;DR: In this article, an upper bound for the number of different constant control vectors constituting the optimal bang-bang control can be derived a priori from the structure of the problem.
Abstract: The limit case of high-frequency optimal processes is analyzed. An upper bound for the number of different constant control vectors constituting the optimal bang-bang control can be derived a priori from the structure of the problem. Therefore, the optimal solution can be easily determined via mathematical programming.
TL;DR: In this paper, a general perturbation technique for dealing with nonlinear problems in the neighborhood of branching points is presented, which is then applied to the treatment of several problems in fluid mechanics, i.e., shock wave in an inviscid and a viscous gas, shock structure in kinetic theory, shock waves in mixtures and ionized gases.
Abstract: A general perturbation technique for dealing with nonlinear problems in the neighborhood of branching points is presented. The general method is then applied to the treatment of several problems in fluid mechanics, i. e. shock waves in an inviscid and a viscous gas, shock structure in kinetic theory, shock waves in mixtures and ionized gases, onset of instabilities in a fluid.
TL;DR: In this paper, the possibilities offered by a particular application of the convolution technique to the quantitative analysis of pulse-height distributions are treated and discussed, and the possibilities of using convolutional neural networks (CNNs) for this purpose are discussed.
TL;DR: In this article, a method is shown to quantify the response of a structure to earthquakes, for linear structures on an elastic half-space, and a method to distinguish the cases in which a significant interaction between soil and structure is expected.
Abstract: A METHOD IS SHOWN TO CALCULATE THE RESPONSE-SPECTRUM OF EARTHQUAKES, FOR LINEAR STRUCTURES ON AN ELASTIC HALF SPACE. A VARIETY OF CALCULATIONS ARE PRESENTED TO ILLUSTRATE THE EFFECT OF FOUNDATION COMPLIANCE AND ENERGY LOSS DUE TO SEISMIC WAVE RADIATION. IT IS FOUND THAT UNDER CERTAIN CIRCUMSTANCES THE INTERACTION BETWEEN SOIL AND STRUCTURE CAN BE QUITE EFFECTIVE IN REDUCING THE RESPONSE OF A STRUCTURE TO EARTHQUAKE EXCITATION. A METHOD IS PRESENTED TO DISTINQUISH THE CASES IN WHICH A SIGNIFICANT INTERACTION IS EXPECTED. /ASCE/
TL;DR: The delayed neutron emission following fission can be used for the analysis of mixtures of fissile nuclides with various techniques, such as irradiation in different neutron spectra from a thermal reactor as mentioned in this paper.
TL;DR: An upper bound on the dimension of a minimal internal description of a linear time-invariant dynamical system described by means of its transfer function matrix is computed, and a simple algorithm is proposed for constructing a realization having dimension equal to that upper bound.
Abstract: A linear time-invariant dynamical system described by means of its transfer function matrix is considered, and an upper bound on the dimension of a minimal internal description of the system is computed. This upper bound is also the minimal dimension of a realization having an invariant structure with respect to the coefficients of the transfer-function matrix for a given location of its distinct poles. Finally, a simple algorithm is proposed for constructing a realization having dimension equal to that upper bound.
TL;DR: The characteristics of an interactive software system, intended to constitute an interface between designer and computer during various steps of the design process, are presented and the adopted design criteria provide sufficient generality to extend the use of the two languages to different computer-assisted applications.
Abstract: The characteristics of an interactive software system, intended to constitute an interface between designer and computer during various steps of the design process, are presented. The main emphasis is given to the description of the features of the two high level user oriented languages, operating at different levels, on which the interaction is based. The first one is IMOL, an interactive monitor language, which is designed to perform the overall and control functions of the software system; its design criteria provide the user with commands which are both simple and efficient in order to perform all the functions needed in computer-aided circuit design. The second one is COIF, a circuit oriented graphic language, which is designed to describe, generate, and manipulate graphic problem specifications~ it is an extension of Fortran with graphictype variables, so that the designer who is familiar with Fortran need not learn a new language. The application to computer-aided circuit design is in particular examined; on the other hand, the adopted design criteria provide sufficient generality to extend the use of the two languages to different computer-assisted applications.
TL;DR: In this paper, a new theorem in nonserial dynamic programming is presented, which generalizes a previous one of the authors, allowing, in the cases in which it can be employed, cutting down the computational effort for solving the secondary optimization problem.
TL;DR: In this paper, the half-life of the ground state of 114 In has been evaluated by statistical methods based on the deviation from the Poisson statistics of the counts due to the radiation of a two-step cascade.
TL;DR: A procedure for the design of nearly optimum unconditionally stable phase-lock demodulators is given in this article, where various noise contributions at threshold are investigated and procedures to reduce the noise due to losses of lock are discussed.
Abstract: A procedure for the design of nearly optimum unconditionally stable phase-lock (PL) demodulators is given The various noise contributions at threshold are investigated and procedures to reduce the noise due to losses of lock are discussed Experimental results of a nearly optimum 24-telephone-channel PL demodulator equipped with a particular type of threshold noise compensator are given
TL;DR: In this article, an experimental research on the behavior of an elastoplastic oscillator with one degree of freedom is described and some differences with respect to the results of studies on a bilinear isteretical model are found.
Abstract: We describe an experimental research on the behavior of an elastoplastic oscillator with one degree of freedom and we point out some differences with respect to the results of studies on a bilinear isteretical model Therefore a mechanical scheme of an elastoplastic oscillator endowed with a continuous skeleton intrinsec curve is studied and the results of the theory agree with the experimental ones
TL;DR: In this article, a min-max algorithm for the problem of finding the optimal frequency of the periodic process with given initial conditions is presented. But the main feature of the algorithm is that at every step a lower bound of the value of the performance index to be minimized is provided, so that the ratio between the minimum at hand and such a bound can be assumed as a meaningful end-test for the searching plan.
TL;DR: A deterministic approach to the reconstruction of convex polyhedra from two perspective images is presented, and the complications introduced by a quantization effect on such images are examined.
01 Jan 1970
TL;DR: The characteristics and architectural applications of aluminum foam materials are presented and, based on these specific characterizations, the most valuable applications along with advantageous in architectural works are discussed.
Abstract: The application of aluminum foam materials is increasing rapidly due to the high demand during the last decades. This research presents an overview of the characteristics and architectural applications of aluminum foam materials. Moreover, it represents the most relevant properties, in particular, physical and mechanical aspects and figures out the prospects and growth rate of these materials in architectures by considering the economic benefits. Besides, based on these specific characterizations, the most valuable applications along with advantageous in architectural works are discussed.