Search

A two-unit standby redundant system with repair and preventive maintenance is considered under the following assumptions: (I) the inspection of an operative unit is made only if the other unit is in standby; and (II) an operative unit, which forfeited inspection due to assumption (I), undergoes inspection just upon repair completion of the failed unit (or inspection completion). We derive the Laplace-Stieltjes transform of the cumulative distribution function of the time to the first system failure and the mean time to the first system failure. Further, we obtain the necessary and sufficient conditions for an optimum preventive maintenance policy to exist with respect to the mean time to the first system failure. More importantly, under certain conditions, we find the analytical form of an optimum inspection time maximizing the mean time to the first system failure. A numerical example is presented.

Magnetic defects disturbing the reliable operation of bubble domain devices were detected by scanning an arrayed stripe domain band which was generated by a pair of permanent magnets. A condition suitable for the defect detection was examined, especially as for the magnetic field gradient applied. Comparative values of the coercive fields of the defects were deduced by the measurement of the field difference along the full length of the stretched stripe domains pinned by the defects. An instrumental technique has been devised for automatic imperfection mapping. Electrical signals from a scanning line on a TV monitor are used for the detection. Imperfections are plotted on an X-Y recorder by amplifying the signals. This sensitive method easily located imperfections found with difficulty by other methods and has been successfully used to evaluate the LPE garnet films for device applications.

The rate of micelle-monomer conversion in a surfactant solution has been determined by two principal methods; the relaxation method including stopped flow, pressure jump, temperature jump, and ultrasonic absorption on the one hand, and the magnetic method utilizing the analysis of signal shape of NMR or ESR on the other. The examination of published data revealed that the rate constants obtained by the relaxation method were generally smaller than those estimated by the magnetic method. The discrepancy seems to originate mainly from the different models of micelle-monomer conversion assumed at the interpretation of experimental data. In this paper is proposed a new analysis of relaxation data, by which the discrepancy can be eliminated or at least much reduced.

Surface tension, electrical conductivity, light scattering and nuclear magnetic resonance measurements were carried out in aqueous solutions of a series of ω-phenylalkyltrimethylammonium bromides. The conclusion is summarized as follows. 1) The pentyl and higher homologs form micelles in aqueous solutions, provided the concentration is larger than a definite value (CMC). As expected, CMC decreases and association number of a micelle increases with an increase in the alkyl-chain length. 2) The butyl derivative does not form large aggregates that are qualified to be called “micelles”. No distinct CMC is observed. 3) In a micellar solution, surfactant molecules are rapidly exchanged between micelles and bulk water phase. 4) Critical micelle concentration is affected by the introduction of a phenyl group at the end of an alkyl chain in such a manner as if 2.7 methylene groups were introduced.

Adsorption and desorption on BET surfaces with finite allowable layers can be simulated by using the Monte Carlo method. For the following two cases, the numbers of adsorbed molecules have been calculated as a function of time. 1. A simple BET surface is placed under a constant concentration of adsorbate. 2. A BET surface including blind holes is placed under a constant concentration of adsorbate. Neither adsorption nor desorption takes place on any site in a hole so long as the site situated at the entrance of the hole is occupied by one or more adsorbate molecules.

Excitation curves for the products of the Be9+p reaction and several angular distributions for the Be9(p, α0)Li6 and Be9(p, d0)Be8 reactions have been measured for bombarding energies from 1.00 to 4.60 MeV. Showing the typical behaviours for direct reaction mechanism, the results have been compared with the pick-up theory in plane-wave Born approximation.

A stable radicalt-butyl-(1,1-dimethylpentyl)-nitroxide was synthesized and solubilized to saturation into a series of sodium dodecyl sulfate (SDS) solutions of increasing concentration. Any solution whose concentration was below the critical micelle concentration (CMC) showed an ESR spectrum composed of a triplet signal, each branch of which formed a narrowLorentzian curve. Above the CMC, the signal shape varied with the change of concentration in a complicated manner, and finally merged into a broaderLorentzian singlet at an extremely high concentration. The spectral change was interpreted in terms of the incessant exchange of radical molecules between micelles and the bulk water phase surrounding micelles. The average stay-time of a radical molecule in a micelle and the mole fraction of micellar radical were determined by comparing experimental spectra with computer-generated theoretical spectra. As expected, the mole fraction of micellar radical increased monotonically with an increase in SDS concentration. The fact that a definite stay-time (3.3 · 10−6 sec) was obtained at all concentrations exceeding the CMC suggests that an increase in surfactant concentration causes the number of micelles to increase without a notable change in micelle structure.

The light scattering of methoxy polyoxyethylene decyl ethers solubilizing n-decane or n-decanol has been studied at the various solubilizate/surfactant ratios. Reduced intensities obtained were analyzed according to Debye's treatment. The micellar weights increase with the addition of solubilizates within the saturation limit, and it is shown that the solubilization process is accompanied by the reconstitution of micelles.

Proton magnetic resonance spectra of benzene solubilized to saturation in deuterium oxide solutions of sodium dodecyl sulfate (SDS) and of trimethyldodecylammonium chloride were examined. The benzene signal did not shift until the surfactant concentration reached the critical micelle concentration, when it then began to shift abruptly. With a further increase in surfactant concentration, the signal shifted asymptotically to a definite position. The same phenomenon was observed with hydrogen oxide solutions of SDS.

Deuterons from the ( 3 He, d) reaction on N =82 nuclei 140 Ce and 142 Nd have been measured at an incident energy of 27.30 MeV with a broad-range magnetic spectrograph. Up to 3 MeV of excitation, levels of 141 Pr at energies 0.0, 0.15, 1.14, 1.32 and 1.64 MeV and those of 143 Pm at 0.0, 0.28, 0.96, 1.17 and 1.40 MeV were observed. The differential cross sections for the transitions were analyzed with distorted-wave calculations. Values of the orbital angular momentum of the transferred proton and the spectroscopic factors of the transitions were obtained.

Adsorption and desorption phenomena can be simulated by using the Monte Carlo method. The following four cases were examined. 1. ALangmuir surface is placed under a constant concentration of adsorbate. 2. ALangmuir surface is placed in a system which contains a definite number of adsorbate molecules. 3. TwoLangmuir surfaces coexist in a system which contains a definite number of adsorbate molecules. 4. ALangmuir surface comprising blind holes is placed under a constant concentration of adsorbate. Neither adsorption nor desorption takes place on any site in a hole so long as the site situated at the entrance of the hole is occupied by an adsorbate molecule.

Evidence for the proximity 3 He(n, p) 3 H reaction in the final state of the sequential 6 Li(d, 3 He) 5 He(n) 4 He process was observed. The behaviour of the positions of the peaks in the two-dimensional spectra was consistent with kinematical predictions. It should be emphasized that the proximity scattering was extended to a rearrangement process. The strength of the process gave direct information on the lifetime of the ground state of 5 He. A classical estimate led to τ = 1.4 × 10 −21 sec, which is the shortest nuclear lifetime directly measured. The consistency of this value with the level width gives quantitative support for the occurrence of the proximity reaction.

Angular distributions of the α-particle groups in the40Ca(3He, α)39Ca reaction were measured atEL(3He)=24.4 MeV by the use of a broad range magnetic spectrograph. α-particle groups corresponding to excitation energies in39Ca of 0, 2.47±0.03, 2.80±0.03, 3.03±0.05, 3.95±0.03, 4.02±0.03, 5.07±0.05, 5.40±0.05, 5.70±0.1 and 6.05±0.05 MeV were observed. The DWBA analysis shows that the ground state and the first excited (2.47) state consist mainly of a (1d1/2)−1 and a (2s)−1-neutron hole state, respectively. The (1d5/2)−1 hole state is considered to split into the 5.07, 5.40 and 6.05 MeV levels with nearly equal fractions. The angular distribution corresponding to the 2.80 MeV level suggests anl=3 neutron pick-up, which is due to the configuration mixing with 1f7/2 neutron shell in the ground state of40Ca.

The level structure of 46 Ti has been studied by means of the 45 Sc( 3 He, d ) 46 Ti reaction with 24.3 MeV 3 He particles. Thirty-eight deuteron groups have been observed with a broad-range magnetic spectrograph up to an excitation of 8.5 MeV in 46 Ti. Angular distributions were measured and compared with DW calculations to obtain values of the orbital angular momentum transfer and spectroscopic information. For most of the angular distributions there is considerable mixing from shells other than 1 f 7/2 . Energies and spectroscopic factors of low-lying levels are compared with those calculated with the pure (1 f 7/2 ) 6 comfiguration model. Coparison with 50 Cr, a cross-con-jugate nucleus of 46 Ti, is also made.

The reaction F 19 ( p , α 0 )O 16 was studied with the bombarding energies of a few MeV proton. Excitation curves were measured at 90° and 135° (1ab.) from 2.24- to 3.35-MeV with the energy step of about 20 KeV. The angular distributions were measured at twelve energies in the region between 2.64- and 3.35-MeV. Most of the angular distributions are asymmetric with respect to 90° (C. M.). The data were analyzed with the theory of fluctuation and the coherence energy \(\varGamma\) was found to be 60 KeV, which corresponds to the lifetime of compound nucleus τ of 1.1×10 -20 sec.. The ratio of the direct reaction to the compound process, x D =σ D / , was found to be zero at 90° (1ab.) and 0.90 at 135° (1ab.) and also for the integrated cross section.

A fully computerized cement rotary kiln process control was tested in a real production line and the results are presented in this paper. The controller design was based on the understanding of the process behavior obtained by careful statistical analyses, and it was realized by using a very efficient statistical identification procedure and the orthodox optimal controller design by the statespace method. All phases of analysis, design and adjustment during the practical application are discussed in detail. Technical impact of the success of the control on the overall kiln installation is also discussed. The computational procedure for the identification is described in an Appendix.

In this paper is described a simulation technique applicable to the gel filtration of an ionic surfactant in the presence of an electrolyte. The applicability was tested by using sodium dodecyl sulfate as a surfactant and sodium chloride as an added salt. In qualitative aspects, the theoretical elution curves showed good agreements with the experimental ones. Disagreements found between both elution curves seemed to be ascribable to the adsorption of the surfactant on the gel surface which was neglected in the theory.

To an aqueous solution of methoxy-polyoxyethylene decyl ether (a non-ionic surfactant), various amounts of a long chain alkyl compound such as hydrocarbon, alcohol, acid, amine or chlorohydrocarbon, were added. Saturation amounts of solubilization, clouding points and phase separations in these systems were observed and the result is represented diagrammatically. The structure of each phase is discussed, based on the analysis of surfactant and distribution of added dye, taking also into account the light-scattering informations.

The low-lying states in 29 P were excited by the reaction 28 Si( 3 He, d) 29 P. The analysis of the reaction in terms of the direct reaction process yielded the orbital angular momenta of the transferred protons and the relative values of the proton widths. The reduced proton width obtained from the experiment are generally in agreement with the values predicted on the Nilsson model with small deformation. A number of low-lying levels were found to have very small proton widths. This fact is accounted for as the effects of the rotational excitation and the band mixing of the excited levels. The measurement of the nucleon width may be useful to clarify the property of the excited level.

The (3He, d) reaction on 116Sn, 118Sn and 120Sn has been studied with 28.2 MeV 3He particles. Deuteron spectra have been measured with a broad-range magnetic spectrograph. Information on the nuclear structure of 117Sb, 119Sb and 121Sb has been obtained from the distorted-wave Born-approximation analysis of angular distributions of various deuteron groups. The 11 2 − state has been located at 1.32, 1.37 and 1.42 MeV in 117Sb, 119Sb and 121Sb, respectively. The lowest lying 5 2 + , 7 2 + and 11 2 − states in each of the three nuclei have been found to be of rather pure single-particle character, whereas the lowest lying 1 2 + and 3 2 + states are found to be seriously mixed.

A statistical consideration is presented on the solution state of a polysoap molecule, in which soap-like groups are situated with a definite interval along the long backbone of a polymer. Under the assumption that the association of soap-like groups occurs only between neighboring groups, two parameters s and σ have been introduced. The former parameter s is the statistical weight to be given for the incorporating of a soap-like group into an aggregate of soap-like groups (an intramolecular micelle) that is already formed, while σ s is the weight for combining two non-associated soap-like groups into an aggregate. In typical polysoaps, the following three conditions are postulated. 1. s larger than unity, but not extremely large. 2. σ smaller than unity. 3. fairly large number of soap-like groups n.

Angular distributions for the 7Li(3He, t0, 1)7Be, and 9Be(3He, t0)9B reactions were measured in the range E( 3 He ) = 3.0–4.0 MeV . In addition excitation curves were measured for 7Li(3He, α0, 2)6Li and the reactions mentioned above over the range E( 3 He ) = 2.0–4.2 MeV . The emitted tritons were identified by means of a magnetic spectrometer and a solid-state detector. The observed angular distributions were fitted with the theoretical curves which were calculated from the cut-off Born approximation with exchange effect. The cluster reduced widths for the mass-3 particles in the mass-7 and 9 nuclei were deduced by comparing the absolute value of the angular distributions with the theoretical differential cross section for incoherently mixed “knock-on” and “heavy-particle stripping” reactions.

The lymphocytes from the patients with primary immunodeficiency diseases and those under immunosuppressive conditions such as viral infection or administration of antimetabolites were studied by various parameters of T- and B-lymphocytes. T-lymphocyte specific antigen, spontaneous rosette formation with sheep erythrocytes, phytohaemagglutinin response of the lymphocytes and delayed hypersensivity skin reaction were used to assess T-lymphocytes, while complement receptor, surface immunoglobulin, serum immunoglobulin levels and antibody response to antigens were estimated as parameters of B-lymphocytes. 9 of infantile agammaglobulinemia, 8 severe combined immunodeficiency, 5 ataxia telangiectasia, d Di-George syndrome, 11 common variable immunodeficiency, 3 isolated IgA deficiency and 4 cases thymectomized more than 10 years previously were studied and discussed for the results. The peripheral blood lymphocytes, especially T-lymphocytes were reduced in the acute stage of measles infection, while they were increased in infectious mononucleosis caused by EB (Epstein-Barr) virus. Atypical lymphocytes observed in the later disease seemed to originate from mainly T-lymphocytes. Cyclophosphamide had suppressive effect selectively on B-lymphocytes.