Testing the neo-classical and the Newtonian theory of production

We search for regularities observed in the production of goods by studying Finnish data. Despite the heterogeneity of sectoral growth rates in Finland, unit root is observed in annual productions in all main sectors and all manufacturing industries. Thus a linear time trend exists in annual flows of production. This is inconsistent with the static neo-classical theory that assumes firms to produce at their equilibrium flow of production. A different framework is thus needed for modeling the behavior of firms. We test a Newtonian type of model for production against the neo-classical one, and our observation is that the former works better with annual data at every manufacturing industry in Finland.     

Three-dimensional structure and defects in colloidal photonic crystals revealed by tomographic scanning transmission X-ray microscopy

Self-assembled colloidal crystals have attracted major attention because of their potential as low-cost three-dimensional (3D) photonic crystals. Although a high degree of perfection is crucial for the properties of these materials, little is known about their exact structure and internal defects. In this study, we use tomographic scanning transmission X-ray microscopy (STXM) to access the internal structure of self-assembled colloidal photonic crystals with high spatial resolution in three dimensions for the first time. The positions of individual particles of 236 nm in diameter are identified in three dimensions, and the local crystal structure is revealed. Through image analysis, structural defects, such as vacancies and stacking faults, are identified. Tomographic STXM is shown to be an attractive and complementary imaging tool for photonic materials and other strongly absorbing or scattering materials that cannot be characterized by either transmission or scanning electron microscopy or optical nanoscopy.     

Kinetic (T = 201-298 K) and equilibrium (T = 320-420 K) measurements of the C3H5 + O2 ⇆ C3H5O2 reaction

The kinetics and equilibrium of the allyl radical reaction with molecular oxygen have been studied in direct measurements using temperature-controlled tubular flow reactor coupled to a laser photolysis/photoionization mass spectrometer. In low-temperature experiments (T = 201-298 K), association kinetics were observed, and the measured time-resolved C(3)H(5) radical signals decayed exponentially to the signal background. In this range, the determined rate coefficients exhibited a negative temperature dependence and were observed to depend on the carrier-gas (He) pressure {p = 0.4-36 Torr, [He] = (1.7-118.0) × 10(16) cm(-3)}. The bimolecular rate coefficients obtained vary in the range (0.88-11.6) × 10(-13) cm(3) s(-1). In higher-temperature experiments (T = 320-420 K), the C(3)H(5) radical signal did not decay to the signal background, indicating equilibration of the reaction. By measuring the radical decay rate under these conditions as a function of temperature and following typical second- and third-law procedures, plotting the resulting ln K(p) values versus 1/T in a modified van't Hoff plot, the thermochemical parameters of the reaction were extracted. The second-law treatment resulted in values of ΔH(298)° = -78.3 ± 1.1 kJ mol(-1) and ΔS(298)° = -129.9 ± 3.1 J mol(-1) K(-1), with the uncertainties given as one standard error. When results from a previous investigation were taken into account and the third-law method was applied, the reaction enthalpy was determined as ΔH(298)° = -75.6 ± 2.3 kJ mol(-1).     

Rayleigh waves obtained by the indeterminate couple-stress theory

Rayleigh waves in a linear elastic couple-stress medium are investigated; the constitutive equations involve a length parameter l that characterizes the microstructure of the material. With , c_T=conventional transversal speed and q=wave number, an explicit expression is derived for the relation between , lq and Poisson's ratio ν. The Rayleigh speed turns out to be dispersive and always larger than the conventional Rayleigh speed. It is of interest that when lq=1 and ν≥0, it always holds that . The displacement field is investigated and it is shown that no Rayleigh wave motions exist when lq→∞ and when lq=1, ν≥0. Moreover, a principal change of the displacement field occurs when lq passes unity. The peculiarity that no Rayleigh wave motions exist when lq=1, ν≥0 may support the criticism by Eringen (1968) against the couple-stress theory adopted here as well as in much recent literature.     

Large strain elasto-plastic model of paper and corrugated board

An anisotropic elasto-plastic constitutive model of paper material is presented. It is formulated in a spatial setting in which anisotropic properties are accounted for by use of structural variables. A multiplicative split of the deformation gradient is employed to introduce plasticity. A similar approach is used to model the plastic deformation of the substructure. The yield surface adopted is based on the Tsai–Wu failure criterion, used previously to model failure of paper material. A non-associated plasticity theory is employed to calibrate the model to experimental data. It turns out that a multi-axial loading situation is needed to calibrate the model and here a biaxial tension test is audited. The model was implemented into a finite element environment and the creasing process of a corrugated board panel is investigated.     

Stresses in a hollow rotating cylindrically orthotropic tube

Explicit stress distributions for a hollow cylindrically orthotropic tube due to spinning are presented for immediate use in everyday engineering work. The solutions are obtained directly without using the stress function concept. Various boundary condition combinations present in practical applications are considered. Examples are given in order to indicate how the degree of anisotropy influences the stress distributions.Department of Mechanical Engineering, University of Oulu, P.O. Box 444, 90571 Oulu, Finland. Published in Mekhanika Kompozitnykh Materialov, Vol. 32, No. 6, pp 835–841, November–December, 1996.     

Compression of character strings by an adaptive dictionary

A new technique for compression of character strings is presented. The technique is based on the use of a dictionary forest which is built simultaneously with the encoding and decoding. Codes representing substrings are addresses in the dictionary forest. Experimental results show that the length of the text can be reduced more than 50% with no a priori knowledge of the nature of the text.     

Synthesis and structures of (3-methyl-2-pyridyl)diphenylphosphane derivatives of metal clusters

An unsymmetric bidentate ligand (3-methyl-2-pyridyl)diphenylphosphane (P(Mepy)Ph₂) is able to react with various tetranuclear transition metal clusters such as HRuCo₃(CO)₁₂, HRuRh₃(CO)₁₂ and Rh₄(CO)₁₂. The synthesis and crystal structures of HRuCo₃(CO)₁₀(P(Mepy)Ph₂) (1), HRuRh₃(CO)₁₀(P(Mepy)Ph₂) (2), RuRh₂(CO)₉(P(Mepy)Ph) (3) and Rh₆(CO)₁₄(P(Mepy)Ph₂) (4) are described. In 1, 2 and 4 the phosphane ligand replaces the carbonyls and acts as a bridging bidentate P-N group. The formation of 3 includes degradation of both the metal cluster core and the ligand itself. One of the P-C bonds in the ligand is cleaved and the ligand caps a metal triangle with a bridging phosphido group together with the nitrogen donor. The reaction between dinuclear Rh₂(CO)₄Cl₂ and P(Mepy)Ph₂ gives a binuclear Rh₂(μ-CO)Cl₂(P(Mepy)Ph₂)₂ (5) with bridging ligands in a head-to-tail arrangement. The crystal structure is also given.