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The discrete elements of finite dimensions which replace the structural continuum in the finite element method can always be chosen sufficiently small that the linear relations between element deformations and element stresses remain valid to the same degree of approximation as is considered acceptable in the linear theory of elasticity. This observation formed the basis for the treatment of geometrical nonlinearities by Argyris and his co-workers in their natural mode technique [1]and [2]. Here we give an alternative development of the theory. The element deformations, linearly related to nodal displacements and rotations in a local coordinate system, are expressed as analytic functions of the nodal coordinates in the global system. Then, for structures with an initially linear behaviour, the stability and postbuckling analysis is developed on the basis of the general theory founded by Koiter [3]. The theory is illustrated by the example of frame-structures. The location of the nodal points is defined in terms of the displacement vector, while the orientation of an orthogonal triad attached to each nodal point is described by means of modified angular coordinates of Euler. The accuracy of the analysis is demonstrated for a problem solved analytically by Koiter [5]and verified experimentally by Roorda [4].

Certain compounds exert specific effects on various properties of steels. It is therefore of interest to know the concentrations of these compounds to correlate composition with heat treatments and properties. Differential thermal analysis and effluent gas analysis can be used to characterize and to determine quantitatively certain metal carbides and nitrides that can be isolated from the steel matrix. Such techniques have been used for the determination of M23C6 type carbide in certain stainless steels and for the determination of TiC, TiN, TiCxNy in 18% Ni, 8% Co maraging steels.

An apparatus allowing simultaneous emanation thermal analysis (ETA), differential thermal analysis (DTA) and evolved gas detection (EGD) is described and its use is demonstrated on the study of the thermal decomposition of calcium carbonate.

The statistical technique of “correspondence analysis”, a variation of “factor analysis” proves itself to be a satisfactory means of differentiating facies in apparently homogeneous sediments. The advantages of this technique are numerous. It permits: 1. (1) Rapid synthesis of large quantities of data. 2. (2) Correlation of microfossils with the environment which contains them, and consequently differentiation of the sedimentary facies, even in extremely homogeneous sediments. 3. (3) Determination of the “significant parameters” of a facies. 4. (4) Objective classification of sediment components as a function of their genesis and sedimentary history. In the present study, more than 20,000 raw data are treated. Four distinctive sedimentary facies are thus identified within six homogeneous Holocene cores from the Persian Gulf. Correspondence analysis shows that, in facies analysis of deltaic sediments, the fine subfraction (0.125-0.063 mm) is the significant one and that the significant sand components are the following ones: ostracods, ophiurids, muscovite, biotite, arenaceous foraminifera, worms, lamellibranch molluscs, gastropods, echinoids and faecal pellets. Correspondence analysis of the sand fraction of Pleistocene sediments leads to the differentiation of two facies, that are readily compared and identified with the above-mentioned Holocene sedimentary facies. Absence of post-depositional transport of sediment is also pointed out by means of correspondence analysis.

A spectral moment analysis of the line shape function ωϵ 2 (ω) in the region of the (0—0) band of the 4000 A 1 B 2u ← 1 A g transition in crystal anthracene at various temperatures is performed. The data are compared with the predictions of three coupling models, viz., weak exciton—photon with weak exciton—phonon coupling, strong exciton—photon with weak exciton—phonon coupling, weak exciton—photon with strong exciton—phonon coupling. The terms contributing to each spectral moment for each model are rendered explicit. The experimental data indicate that the exciton—intermolecular phonon coupling is primarily weak. The exciton interacts with optical phonons of about 90 cm -1 frequency with a coupling strength of about 140 cm -1 , a value near that predicted by a weak coupling model. The coupling strength is nearly the same irrespective of whether the exciton is created by b - or a -polarized light probably indicative of the importance of higher multipole contributions to the coupling although the existence of strong interband scattering could affect that suggestion. The coupling parameters g op and g ac are about 10 -1 and 10 -4 respectively.

Thermal analysis studies of the alkylammonium tetrachloro-, tetraphenyl- and trichlorophenylborates demonstrates formation of 1:1 complex by loss of hydrogen chloride or benzene. Further decomposition in both the tetrachloro- and the trichlorophenylborate systems leads to formation of the B-trichloro-N-trialkylborazine. Decomposition of the tetraphenylborates stops at the borazene stage with formation of the alkylaminodiphenylborane.

A new apparatus is described which permits the simultaneous recording of the differential thermal analysis and gas evolution curves for a given sample from ambient to 900°. The sample is pyrolyzed in a dynamic helium gas atmosphere using a conventional DTA furnace and sample holder assembly. The evolved decomposition products are detected in the helium gas stream by means of a thermistor thermal conductivity cell. From a knowledge of the GE curve and an analysis of the decomposition products, a more accurate interpretation of the DTA curve can be made.

The construction and use of an instrument designed to facilitate research into analysis by quantitation of chromatographed zones is described. The instrument determines and records on computer tape the UV transmittance at 0.5 × 0.5 mm intervals in the two dimensions of the thin layer. The application of the general K ubelka -M unk transmission equation to the interpretation of the data is described. The flexibility of the method lies with the analyst who may write computer programmes suited to his analytical problems.

A time series analysis of air monitoring data for the downtown Los Angeles station has been used to forecast pollutant concentrations. Trends are thereby detectable. Hydrocarbon, total oxidant, and carbon monoxide are trending downward. Nitric oxide is trending upward. Sulfur dioxide and nitrogen dioxide are behaving in a complex manner, and no forecast is possible at this time. These statements are based on analysis of the data to the end of 1969. Somewhat different results were obtained using the data to the end of 1967. This emphasizes the empirical, adaptive nature of the time series forecasting and the need for updating. A smog effect diagram was derived from the air monitoring results. From the regression equation and the standard deviations, mutually interconsistent air quality standards have been derived. A set of these is oxidant: 10 pphm; nitrogen oxides: 25 pphm; and nonmethane hydrocarbon 0.6 ppm C. If current trends persist, this work indicates the control program is having an effect in the anticipated direction. Emission standards appear to be consistent with the air quality standards on the basis of the analysis for this station. Data from other stations and other locales could also be productively analyzed by the methods used here.

A mathematical model of a reverse osmosis water purification system that can be used in process optimization studies is developed. A boundary layer flow model is used to relate water production rate to the operating pressure, Reynolds number, and membrane area. Cost equations that relate the capital and operating costs to the design variables are also developed. These relations are then used in economic analysis of several reverse osmosis systems. The results of computer simulation of single stage processes are presented. The model is believed to be accurate enough to describe the process and yet simple enough to be used in the simulation, design, and optimization of the process.

A method for the in situ quantitative analysis of thin layer chromatographic zones on microscope slides is described. It comprises the quantitative application of 1 μl of solution to the plate, two-dimensional scanning of the zone with a point of monochromatic illumination, then off-line data processing by computer so that a simplified form of the general K ubelka -M unk equation for transmission can be applied. The standard deviation observed on independently analysed 0.510 μg loads of acetone dinitrophenylhydrazone on silica gel thin layers using the experimental prototype apparatus is 2.7%.

A new computer approach to handling large numbers of variables in biological systems is introduced. The method, called “Direct Analysis” or “Finite Element Analysis”, reduces the need for closed form solutions, or deriving solutions based on differential or integral equations. Rather, fundamental laws are allowed to interact via computer program in incremental form and can be merged by combining programs to form, in the ultimate, a “bio” system. An overview of the “Method” and “Concepts” underlying this approach is followed by a listing and description of its applications to physical, chemical and biological properties. Its significance and contribution to evolving computer techniques in the life sciences is evaluated.

The sample to be analysed and a standard of known composition were irradiated simultaneously and the induced radioactivity compared. The investigation was done with high resolution Ge (Li) detectors coupled to fully transistorized 400 and 4000 channel analysers. By varying the irradiation time and conditions, it was possible to employ a non-destructive analytical procedure. The concentration of 16 elements, namely, Mg, Na, Cl, Al, Ca, Cr, Ba, Sb, Ag, Zn, Co, Fe, Sr, Au, Br and Mn was determined in normal human enamel and dentine by instrumental activation analysis.

In the comparisons hitherto made between similar-fade analysis results and correlation analysis results of ionospheric drift measurements two essential facts seem to have been left out of account, namely 1. (i) that there are at least two different ways of making similar-fade analysis which often yield quite different magnitudes of drift velocity, and 2. (ii) that the similar-fade method is necessarily confined preferably to the short-period components of the fading and that, therefore, its results may not be a priori comparable with the results of a correlation analysis which includes the long-period fading components as well. From investigations of ionospheric drift measurements in the LF range at medium latitude it can be shown that there are close relationships between similar-fade and correlation analysis results, if correlation analysis is performed after submitting the original fading curves to a mathematical filter which suppresses the long-period fading components. The drift velocity obtained from one variant of the similar-fade method (the method of averaging time delays) is very similar to the term “apparent drift velocity” in the correlation analysis, whereas the drift velocity obtained from the other variant of the similar-fade method (the method of averaging drift vectors) is very similar to the term “true drift velocity” in the correlation analysis. Even the term “chaotic velocity” can approximately be found from the similar-fade method by combining the results of the two variants according to a formula borrowed from the correlation analysis formalism. These relationships, though not yet founded mathematically, are expected to be generally valid also at higher frequencies and in other latitudes, as far as there is no extreme anisotropy of the ionospheric irregularities.

A method of analysis of nonhomogeneous elastic solids involving general three-dimensional states of stress is presented. The displacement equations of equilibrium based on the finite-element variational procedure are derived in the usual manner. The element shape considered is a tetrahedron with linear displacement approximations. p ]The main feature of this paper is the method of solution of the equilibrium equations. This method, called the alternating component iterative method, belongs to the class of block iterative schemes and is particularly suited for problems involving several dependent variables such as the ones encountered in elasticity. The method is presented in a form sufficiently general to permit the utilization of higher-order displacement approximations in the tetrahedral elements. p ]The alternating component iterative method is discussed in detail with respect to the following aspects: the general procedure, convergence criterion, refinement of the solution, and convergence acceleration procedure.

THE PURPOSES OF THIS INVESTIGATION WERE TO DEVELOP MATHEMATICAL MODELS THAT MEASURE THE RELATIVE SAFETY OR HAZARD OF URBAN CROSSINGS AND TO ESTABLISH A PRIORITY RATING SYSTEM, BASED ON THESE MODELS, FOR DETERMINING PROTECTION IMPROVEMENTS IN URBAN AREAS. THE MATHEMATICAL TECHNIQUES OF DISCRIMINANT ANALYSIS AND REGRESSION ANALYSIS WERE UTILIZED TO DEVELOP DISCRIMINANT MODELS WITH LINERLY ASSIGNED PROBABILITIES. THESE MODELS PERMIT POTENTIAL HAZARD TO BE EXPRESSED AS THE PROBABILITY THAT A GRADE CROSSING IS ACCIDENT PRONE. A GRADE CROSSING WHERE A VEHICLE-TRAIN ACCIDENT HAD OCCURRED DURING A TWO-YEAR PERIOD WAS CONSIDERED AS A REPRESENTATIVE MEMBER OF THE POPULATION OF ACCIDENT PRONE CROSSINGS. A LOCATION WHICH HAD NOT EXPERIENCED A VEHICLE-TRAIN ACCIDENT FOR AT LEAST FIVE YEARS PRIOR TO THE DATE OF THE FIELD INVESTIGATION WAS ASSUMED AS A REPRESENTATIVE MEMBER OF THE POPULATION OF NON-ACCIDENT PRONE GRADE CROSSINGS. DATA WERE COLLECTED AT 295 ACCIDENT LOCATIONS AND 281 NON-ACCIDENT LOCATIONS IN URBAN PORTION OF THE STATE OF INDIANA. THE BEST DISCRIMINANT MODEL IS 74 PERCENT SUCCESSFUL IN CLASSIFYING THE TRUE GROUP MEMBERSHIP OF THE SAMPLE GRADE CROSSINGS. THIS MODEL EXPRESSES POTENTIAL HAZARD AS A FUNCTION OF PROTECTIVE DEVICE, AVERAGE DAILY HIGHWAY TRAFFIC, AVERAGE DAILY TRAIN TRAFFIC, DEGREE OF EFFECTIVE SIGHT DISTANCE, AND ROADSIDE DISTRACTIONS. A METHODOLOGY WAS DEVELOPED FOR SELECTING A MINIMUM LEVEL OF GRADE CROSSING PROTECTION AND FOR ESTABLISHING PRIORITIES FOR THE IMPROVEMENT OF PROTECTION AT URBAN RAILROAD-HIGHWAY GRADE CROSSINGS. /AUTHOR/

The stability behavior of a synchronous machine, connected to an infinite bus, is considered. Direct and quadrature axis damper-windings are taken into account and the input torque is said to be zero. The behavior of this machine is characterized by a system of five first-order nonlinear ordinary differential equations containing periodic nonlinear terms. These equations are shown to have two different types of equilibrium points. By means of linearized analysis it is shown that all points of the first type are (locally) asymptotically stable, whereas all points of the second type are (locally) unstable. Stability behavior of the system is analyzed for all initial conditions. This analysis is performed by a combination of various techniques: the second method of Liapunov, the topological methods of Wa[zdot]ewski, extension theory and results of the topological properties of the regions of attraction. These techniques, combined, allow a complete characterization of the stability behavior of the machine. Both global results (the set of all equilibrium points is a global attractor), as well as local results (the trajectory leaving one unstable equilibrium point tends to an asymptotically stable equilibrium point), are proved.

A cross section of basic yet rapidly developing topics in multivariate data analysis is surveyed, emphasizing concepts required in facing problems of practical data analysis while de-emphasizing technical and mathematical detail. Aspects of data structure, logical structure, epistemic structure, and hypothesis structure are examined. Exponential families as models, problems of interpretation, parameters, causality, computation, and data cleaning and missing values are discussed.

A thermal analysis—mass spectrometer system controlled by a computer has been developed and successfully used in the analysis of a wide variety of geochemical samples. The TA—MS computer system provides a very powerful analytical tool for the determination of volatile species released from samples over a very wide temperature and sample-size range. Use of a small laboratory computer and magnetic-tape storage units permits large quantities of analytical information to be handled and easily retrieved. The rapid scan capabilities of the quadrupole mass spectrometer operating under computer control are especially useful for following the rapidly changing composition of the evolved gases released from samples during heating under vacuum conditions. Samples of volatile-rich Green River shale and two lunar soils have been analyzed to show the utility of the TA—MS computer system.

A study has been made of the effects of some variables on the analysis of amino acids using Aminex A5 resin and lithium or sodium citrate buffers. Variation of the Li+ concentration, pH, temperature, and n-propanol concentration of the buffers showed that the last three variables have an effect on the pattern of the amino acid chromatogram. In the case of n-propanol concentration, this effect is quite marked. An accelerated routine method of analysis of either physiological fluids or protein hydrolyzates is presented. Aminex A5 resin is used in four columns, two of which are the same length. One set of four buffers is used. Total analysis time is 12 hr for a physiological fluid and 4 hr for an hydrolyzate. In physiological fluid analysis both asparagine and glutamine can be estimated while all the other amino acids of major interest are well resolved, as are many less common ninhydrin-positive compounds. Unusual components which are not resolved completely in the routine system in certain cases can be resolved by changes in pH or propanol concentration of the buffers. Pressures at the column top do not exceed 300 psi.

Fluoride analysis of the human diet and of excreta were determined using certain modifications of the diffusion method of Singer and Armstrong. This study deals specifically with the fluoride analysis of the diet and stool, although numerous analyses of urine, saliva, and plasma were also carried out. The dietary fluoride content averaged 1.51 ± 0.11 mg per day in the early studies and 1.81 ± 0.08 mg in later studies. The fecal and urinary fluoride content depended on the dietary fluoride intake. The details of the method of analysis of the diet and of the biological samples are described.

Two types of multivariate analysis of cranial metrical data have been tried for the whole Primate Order (Hominoidea excluded). The Prosimian heterogeneous group has been analysed in greater detail. Principal component analysis using the Chi-square metric for 16 parameters resulted in good differentiation of subgroups, often down to generic level. Discriminant analysis pointed out the major importance of the opposition cranium-masticatory apparatus, in the whole order and at all taxonomial levels, together with the high weight of basal width discriminating power for comparison of Primate skulls shape. Thus, it seems legitimate to use such methods in our future research for locating fossil specimens with a limited number of measurements.

The advent of new stains for chromosomes has increased the possibility of implementing useful automated chromosome analysis. The case with which chromosomes can now be recognized makes it possible to perform detailed statistical analysis of the chromosomes of an individual. This paper describes methods for assembling chromosome information from several cells in such a way that accidental variations due to preparation, etc. can be eliminated and an undistorted set of characteristics of the chromosome complement can be established. This set of characteristics can then be compared with various references, and statements can be made concerning the relationships between variations in the chromosome complement and genetic traits. These same methods can be employed in multiple-cell karyotyping to circumvent the classical problem of touching and overlapping chromosomes. The methods also allow one to achieve very reliable descriptions of the chromosome complement. The importance of appropriate descriptors of the chromosomes is illustrated.

An error analysis of the Lindner and Grove et al. methods of computing the high-frequency capacitance of metal-oxide-semiconductor (MOS)_capacitors is presented. The analysis is based upon a differential equation for the capacitance introduced by Sah, Pierret and Tole (the “SPT capacitance”). This equation does not employ the minority-carrier-depletion approximation of Lindner, nor the depletion-width approximation of Grove et al., nor does it require matching different solutions in different bias regions. Consequently, all these approximations can be tested. Our results show that the approximations in the Lindner capacitance introduce only 1 to 2 1 2 per cent deviation from the SPT capacitance in the doping range from 1017/cm3 to 1013/cm3, respectively. The simple Grove capacitance based upon the majority carrier depletion approximation differs by 10 per cent from the SPT capacitance at a band bending 5 kT/q on the depletion side of flatbands, and differs by 6–11 per cent in strong inversion for the same doping range. Finally, it is shown that by resorting to a numerical integration the Lindner capacitance can be made to agree with the SPT capacitance to 10−10 CFB at 1017/cm3 and 10−5 CFB at 1013/cm3 (CFB = flatband capacitance). These results indicate that the SPT calculation is rather well approximated by the Lindner capacitance, and that for most purposes some form of the Lindner capacitance would be adequate. Our results also indicate the level of accuracy that is meaningful in any numerical evaluation of the various calculations. Finally, it should be noted that errors due to overidealizations in the SPT formulation itself have not been evaluated. However, whatever this error may be, the net error in any of the other methods is the sum of the SPT error and the error computed here. Consequently, any future error analysis need not repeat what has been done here, but may confine itself to the error in the SPT calculation.

Methods are derived for the cross spectrum analysis of pairs of two-dimensional velocity vectors or pairs of complex-valued time series in general. These methods are based on a decomposition of the complex-valued series into polarized components. The advantages include: (1) the invariance of coherence under coordinate rotation, and (2) the calculation of coherence and phase for polarized components; i.e. clockwise and anticlockwise components. A (phasor) correlation coefficient as a function of frequency is derived for a pair of complex-valued series. This coefficient includes contributions from both polarized components. The methods may be implemented either by the cross spectrum analysis of a pair of complex-valued series or by combinations of quantities ordinarily computed in the cross spectrum analysis of a set of four real-valued series.

Let be a σ-finite nonatomic measure space. We think of the customary analysis based upon as Continuum Analysis. In contrast, we regard Discrete Analysis as being based upon a countable subset of X rather than upon X itself. The particular version of Discrete Analysis introduced here—we shall call it Poisson Analysis—treats simultaneously all countable subsets of X and distinguishes between them probabalisticly via a counting process whose values are random variables with Poisson distributions. The present paper demonstrates the viability of this idea by applying it to the formal theory of a free Boson field. The customary version of this theory may be phrased in terms of and the related normal Wiener process N . The alternate version introduced here uses, in place of N , what we shall call a Gaussian jump process. We interpret the resulting theory as Discrete Analysis and compare it with the customary theory. In particular we show that the discrete theory already contains the usual one inside it (see Theorem 1), and that, in the discrete case, symmetries are much more readily implementable by unitary transformations.

This paper describes a unique numerical method for linear inviscid fluid hammer analysis based on the method of characteristics. The uniqueness lies in that it uses the analytical solutions of the wave equation in place of the compatibility relatins of the more conventional method of characteristics. The numerical solution is obtained by a simple superposition technique for tracing the waves traveling along each characteristic and extending the solution from one constant time line to the next. Using a predetermined finite difference net of grids with equal spacings, an elimination is made of the spatial interpolation, thereby maintaining the wave amplitudes in their full strength in the numerical procedure. This is in contrast to the case of a nonlinear problem in which the pressure peaks are always flattened to some degree in the interpolation procedure. The computer program NAHAMMER is a system analysis code adequate for short-term pressure transients of most engineering problems of significance involving a moderate pressure source. It considers the simplified one-dimensional, linear, inviscid set of governing equations with an isentropic flow assumption. A closed fluid-network system is considered to be composed of a multiple of one-dimensional pipe sections and components that are connected by various joints. An analytical solution is obtained under an acoustic approximation for a simple system and the result shows good agreement with the numerical solution. As examples of the application of the method, complex problems of engineering importance are calculated and the results are presented.

The reactivity, or availability, of the metal oxide component in various metal oxideA1 2 0 3 catalysts is an important parameter in assessing the performance of catalysts. For CuO on Al 2 0 3 systems, reduction of the CuO with H 2 followed by back oxidation with air gives an indication or measure of the reactivity of the CuO. In order to determine how this reactivity varies with the nature of the support. method of preparation, etc., oxidation—reduction studies have been conducted on a series of experimental catalysts using a Mettler Thermoanalyzer. Thermogravimetric analysis with continuous recording of the weight changes of the catalysts during oxidation- reduction experiments has permitted determination of the “percent reactive CuO” in different catalysts at two different temperatures: 550 and 650°F. In addition to furnishing data and correlations regarding the CuOAl 2 0 3 catalysts, these experiments have demonstrated the potential of thermal analysis for such investigations in general.

Epidemiological studies have shown a positive association between selenium intake and dental caries. The purpose of this study was to determine quantitatively the selenium content of normal human enamel in a racial group with low caries prevalence. Each enamel sample was simultaneously irradiated with a reference standard containing 1 μg of selenium. The irradiations were done for three weeks in a nuclear reactor in a thermal neutron flux of 2 × 1013n cm−2 sec−1. After a cooling period of 3 weeks these samples were dissolved and quantitatively transferred, with selenium carrier, to a distillation apparatus. A selective distillation was carried out and each distillate made up to 25 ml and transferred to a standard plastic container. The gamma-ray activity of 75Se was measured with a 50cm3 coaxial Ge(Li) detector coupled to a fully transistorized 4000-channel analyser. The data were recorded on magnetic tape and afterwards computer-processed. The distillation technique gave a 98 per cent yield of selenium, which makes the method experimentally acceptable. The selenium content of the composite enamel samples was 0.08 ± 0.03 ppm.

The paper examines some of the difficulties and problems of environmental damage cost analysis. The relevance of damage cost analysis to decision making in the R & D field and the potential use of this type of data are discussed.

A critical examination is made of the theories and recommendations of MacCallum and Tanner, Prime, Draper, and Ingraham and Marier concerning the applicability of the Arrhenius equation to the kinetic analysis of data obtained by non-isothermal thermal analysis. Except for the last mentioned, these theories are found to be of questionable validity. It is suggested that a number of factors related to the experimental procedure and the assumptions made about the decomposition processes studied, require more extensive investigation before the theoretical limitations of the Arrhenius equation can be adequately assessed.

A hardware and software system is described for the acquisition, reduction and analysis of neurophysiological data. Application pertains to EEG and EEG-derived evoked potential records. Determination is made of frequency component information in the records using a Fast Fourier Transform algorithm. The frequency information is represented as power spectra estimates (PSE), which are later selected, averaged and input to a multivariate discriminant statiscal package. Control of the software system is made via remote terminal and acoustic coupler, allowing the use of off-site computer support. Sample results are provided.

EEG recordings of ten healthy subjects were obtained during rest with eyes closed, rest with eyes open, mental arithmetic and reading. Spectral analysis and multivariate statistical analysis of spectral values yielded the following results: 1. 1. The percentage of alpha intensity decreased during eye-opening and both mental activities, but did not allow any differentiation between arithmetic and reading. 2. 2. A significant increase in relative beta intensity was found during eye-opening. A further increase occurred during reading, but not during mental arithmetic. 3. 3. An increase in theta percentage during reading and an increase in delta percentage during arithmetic were found to be characteristic for these tasks. 4. 4. The statistical analysis of spectral values of EEG showed a different organization of the EEG in frequency bands. During arithmetic and reading a more complex organization of the EEG within the fast frequencies and changes in the distribution of frequency bands in the subalpha range were found.

How similar are tourists from the audiences of two or more advertising vehicles? The method of N-way multiple discriminant analysis was used for predicting magazine readership from key tourist variables from two samples of 300 coupon inquiries. Results of the analysis indicated similar tourist profiles existed among the readerships of the three magazines. Application of the method used in this study may be useful in the development of promotional themes to attract tourists from selected advertising vehicles and in identifying unique tourism characteristics for particular vehicles.

A method for the analysis of data from perturbed angular correlation, or distribution, experiments is described. The method allows for the presence of a prompt admixture, and is also suited for the analysis of lifetime data involving up to three different decay constants. A computer code utilizing this method of analysis has been developed, and extensively tested.

A generally applicable test using dolomite to detect effects of atmosphere self- generation and to determine atmosphere control in thermal analysis is demonstrated. Either differential thermal analysis (DTA) or thermogravimetry (TG) can be used. In a CO2 atmosphere dolomite produces two separate thermal decompositions, but in a CO2-free atmosphere dolomite decomposes in a single reaction. If two peaks or a shoulder appear on the decomposition response in air, effects of self-generated CO2 are proven. If the reaction in air is not complete by 800°C, self-generated CO2 around the sample is strongly indicated. The dolomite decomposition at lower temperature in CO2 essentially independent of CO2 pressure, can be used to establish a temperature reference point for this atmosphere testing. Thin layers of sample and a gas stream flowing over the sample are shown to be necessary for atmosphere control in thermal analysis.

The serial dilutions commonly employed in hemagglutination titrations give end-points of low precision. This weakness can be overcome by performing sufficient observations to yield mean titers of the desired precision. Statistical analysis thus becomes an important part of experiments depending on this assay. Such analysis is needed not only to interpret objectively available data but also to design future experiments. These two interrelated matters are discussed in detail here but from an introductory level which requires no prior familiarity with statistics. Emphasized throughout this review paper the analysis of variance and the Dunnett multiple comparisons test.

The cobalt(II) salts of some alkanemono- and disulfonic acids have been prepared; all are new and most of them crystallized with six molecules of water. Their behaviour under heating has been studied by thermogravimetric analysis (TG) and differential thermal analysis (DTA). Most of them lose their water in several steps and some anhydrous salts melt; the decomposition begins at a temperature which depends upon the structure of the organic anion and it leads to residues, the composition of which depends on the surrounding atmosphere.

A computerized method of analysis of pluriphase-shaped absorption melting curves, approximated by cubic spline functions, is described. The limiting statistical criteria are presented on examples of analysis of synthetic poly[d(A-T)] and the heterogeneous DNA of the pea ( Pisum sativum ). The derivative absorption melting curve of poly[d(A-T)] consists of one main band (90%) and of at least three minor side bands (even at high probability level of 95%) reflecting its heterogeneity in molecular weight and secondary structure. The pea DNA, having a relatively high number of melting components, was analysed at relatively lower probability levels (below 68%) where twelve physically significant intramolecular melting components of different base composition were found.

A method for systematic analysis and modelling of interacting species is developed. An iterative algorithm for solving the inverse problem in ecological modelling (the problem of using empirical population data to evaluate the parameters of a given model) is first presented. It is then shown that certain results from the theory of statistical hypothesis testing provide a method by which the many possible interspecies interactions in an ecosystem can be examined and the dominant interactions can be identified. This analysis leads to the development of mathematical models which are optimum for a given set of empirical data. An example analysis of a four-species webbed ecosystem is discussed.

This study serves to introduce dimensional analysis to the social sciences. Dimensional analysis, a method fundamental to research in the physical sciences, is presented first in a conceptual framework. Questions such as: what makes the method work, what use is it, and what are its limitations … are dealt with summarily. The method is then applied to the modeling of interurban migration. The selection of independent variables, the synthesis of dimensionless groups, and the analysis of data are considered in some detail. While a blanket endorsement of the method must be withheld pending further research, results of the present study are encouraging. Dimensional analysis may eventually find wide application in the social sciences.

Finite element analysis techniques are becoming increasingly popular for the computer prediction of electromagnetic field distributions in magnetic structures. The triangular mesh employed in such techniques is particularly suited to the study of electromagnetic phenomena occurring at the interface of media having complex boundary geometries and non-linear reluctivities. Convergence, iteration times and mesh subdivision are factors which must be considered when designing finite element algorithms for the computer analysis of such problems. This paper describes the use of a variable acceleration parameter and mesh categorization data which can be used to improve convergence, simplify the iteration process for subdivided meshes and reduce the total computer time required for solution. The techniques are illustrated by predicting the flux distribution within both a circular ferromagnetic bar rotating in a magnetic field, and a stationary bar carrying an axial current.

This paper is concerned with how economic theory traditionally tries to cope with the analysis of technical change. The paper points out some of the shortcomings of conventional analysis and suggests where it needs modification.

Reflectance spectra from 0.2 to 2.65 microns were obtained for several igneous rocks and minerals. The reflectance of all the rock samples, when crushed, increases with decreasing particle size. A statistical analysis established the correlation between reflectance and the wavelength of energy, the generalized composition, and the particle size of the rock samples. Most of the absorption bands present in the spectra correspond to some form of water in the sample, or are common to unrelated rocks and minerals, and, therefore, are not diagnostic of composition. A correlation analysis between the generalized composition variable and the ratios of reflectance at two different wavelengths has indicated correlation coefficients as high as 0.88 and may prove useful in selecting the more characterizing regions of the spectrum for remote sensing experiments.

The size distribution data obtained by screen analysis of a non-uniform substance cannot be used directly in calculating the various average diameters of the material since this method of analysis gives the distribution in terms of weight rather than count. The distribution curve by weight however bears a definite relation to the regular size-frequency curve and suitable transformation equations are presented by means of which one is able to calculate the various average diameters from the parameters of the curve given by the screen analysis. The screens are calibrated in terms of the actual size of the material retained rather than the dimensions of the screen openings or an arbitrary method of calculating the “size of separation.”

SUMMARY A gas chromatographic system for the quantitative analysis of blood-gases has been constructed. The system incorporates a simplified "equilibration" blood-gas extraction and injection unit, and adsorption columns linked in parallel. Eighty μl. of blood is required for each analysis. The time required to carry out duplicate analyses is 8 minutes. Blood oxygen, carbon dioxide and nitrous oxide contents are determined using peak height measurements. Calibration for carbon dioxide is carried out by using carbonate solution, for oxygen by using room air, and for nitrous oxide by using cylinder nitrous oxide. Reproducibility studies were carried out by analyzing one blood sample ten times: coefficients of variation for oxygen, carbon dioxide and nitrous oxide were, in each case, approximately 0.5 per cent. Comparisons of oxygen and carbon dioxide contents of twelve blood samples were simultaneously determined by the gas chromatographic method and by the Van Slyke manometric method. There was close agreement between the two methods; the coefficients of correlation of the respective estimations were +0.999 in the case of oxygen and +0.995 in the case of carbon dioxide.

Clinical application of electroencephalographic monitoring has generally been restricted by the complexity of on-line unprocessed data analysis. A technique has been developed which expands the applicability of clinical e.e.g. monitoring and presents the clinician with an e.e.g. spectral analysis designed specifically for readability in a dynamic environment. In this technique, one or more channels of electroencephalographic data are amplified, frequency-modulated and transmitted over a standard unprocessed, voice grade, direct distance dialling telephone line to a PDP-12 computer (8k memory). This information is processed in 4- or 8-second blocks using fast Fourier transform methods to present a power spectral plot of 0–16 Hertz bandwidth. Successive blocks of data are analysed similarly and plotted by computer direction to give a continuous record of the e.e.g. spectrum. These spectrum plots are simultaneously retransmitted over the same telephone line to the e.e.g. transmission location and plotted on a Y-T recorder. This system is currently being used in the operating room to guide the induction of safe, effective anaesthesia and ensure the adequacy of cerebral oxygenation.

Two lengths of PVC coated copper electrical cable were compared by neutron activation analysis to establish if they had a common origin. Non-destructive analysis of the copper cable revealed the same four trace elements, silver, gold, cobalt and antimony (in similar concentrations) in each exhibit. These results were compared with the results of the analyses of thirteen other samples of copper wire and cable from various origins. The insulating plastics which sheathed the cables were also analysed and compared. Qualitative matching of the plastic coatings was made on the basis of eight trace elements.