Showing papers by "University of Akron published in 1986"

A meta-analysis of the relation between personality traits and leadership perceptions: an application of validity generalization procedures

Abstract: Re-examen de la relation entre des traits de personnalite issus de theories actuelles de la perception sociale et les perceptions du leadership ou l'etendue de l'emergence d'un leader

Solute and penetrant diffusion in swellable polymers. II. Verification of theoretical models

Abstract: A mathematical model developed to describe diffusion of a penetrant and a solute in a swellable polymer slab was applied to the case of a hydrophilic polymer loaded with a soluble drug in which the penetrant (water) is sorbed and solute (drug) is desorbed. An exponential dependence of the penetrant and solute diffusion coefficients on penetrant concentration was chosen and shown to be adequate for description of the systems studied. Experimental verification of the model was conducted by using copolymers of 2-hydroxyethyl methacrylate (HEMA) and N-vinyl-2-pyrrolidone (NVP). The monomers were bulk polymerized with benzoyl peroxide initiator and cut into thin disks. Monomer mole fractions of HEMA in the copolymers were 0.707, 0.446, and 0.211. Swelling behavior of the samples was observed in water at 37 and 0°C. Solute-containing samples were prepared and solute release from these samples into water was followed by monitoring the UV absorption of the release medium. The concentration dependence of the diffusivity of water and two model solutes, sodium trifluoroacetate and sodium heptafluorobutyrate, in the gels was studied by using the pulsed-gradient spin-echo NMR technique. The diffusivities measured by this technique followed the concentration dependence predicted by the free-volume theory. The simple exponential dependence used in the model was an adequate approximation of this behavior in the case of a transient diffusion experiment.

Living carbocationic polymerization

Abstract: A new family of initiating systems has been discovered that efficiently induces the truly living polymerization of isobutylene (IB). The initiating systems are complexes of organic tertiary esters e.g., cumyl acetate, 2,4,4-trimethylpentane-2-acetate, with BCl3. Living polymerizations proceed very rapidly in a variety of solvents, i.e., CH3Cl, CH2Cl2, C2H5Cl, and mixtures of chlorinated solvents plus n-hexane, in the range from −10° to −50°C. The living nature of the polymerizations was demonstrated by linear ¯Mn versus WPIB (g of polymer formed) plots starting at the origin and horizontal N (number of PIB chains) versus WPIB plots. The DPn of the products obeys [Mo]/[Io] where [Mo] and [Io] are initial monomer and initiator concentrations, respectively. Conversions and initiator efficiencies are ∼100%. In carefully controlled experiments narrow molecular weight distribution polyisobutylenes (PIB) have been obtained, i.e., Mw/Mn=1.17 − 1.3. A mechanism is outlined that helps rationalize the findings. It is postulated that the living polymerization of IB initiated by organic tertiary ester·BCl3 complexes most likely proceeds by a two-component group transfer polymerization process.

Effects of personal involvement: Thought-provoking implications for social loafing.

Abstract: In 1979, Latane, Williams, and Harkins observed that individuals working together put out less effort than when they work alone, an effect these researchers termed social loafing. Subsequent research (Williams, Harkins, & Latane, 1981) has suggested that this effect arises, at least in part, because when participants work with others on these tasks their individual outputs are lost in the crowd, and, thus, they can receive neither credit nor blame for their performances. However, it is unlikely that participants found the tasks used in these experiments (e.g., clapping, shouting) to be involving. The possibility that personal involvement could moderate the social loafing effect was tested in a 2 (high/ low involvement) X 2 (high/low identifiability) factorial design across three replications. Replicating previous loafing research, we found that under conditions of low involvement, participants whose outputs were identifiable worked harder than those whose outputs were pooled. However, when the task was personally involving, the loafing effect was eliminated. Participants whose outputs were pooled worked as hard as those participants whose individual outputs could be identified.

The Poisson Function of Finite Elasticity

Abstract: The Poisson function is introduced to study in a simple tension test the lateral contractive response of compressible and incompressible, isotropic elastic materials in finite strain. The relation of the Poisson function to the classical Poisson’s ratio and its behavior for certain constrained materials are discussed. Some experimental results for several elastomers, including two natural rubber compounds of the same kind studied in earlier basic experiments by Rivlin and Saunders, are compared with the derived relations. A special class of compressible materials is also considered. It is proved that the only class of compressible hyperelastic materials whose response functions depend on only the third principal invariant of the deformation tensor is the class first introduced in experiments by Blatz and Ko. Poisson functions for the Blatz-Ko polyurethane elastomers are derived; and our experimental data are reviewed in relation to a volume constraint equation used in their experiments.

Perceived risk and the selection of a retail patronage mode

Abstract: Consumers can select products from a wide variety of retail patronage alternatives. This article examines the amount of perceived risk that is associated with shopping at six different patronage modes. Department and specialty stores are generally considered low risk modes, while media advertisements represent the highest risk alternative. This research also examines the importance of various risk-handling tactics that may help the consumer deal with the perceived risk involved with the selection of a particular retail patronage mode.

Institutional Sexism in the Underworld: A View From the Inside

Abstract: In this report we examine the views of male thieves toward women as potential accomplices or partners in crime. Our interviews revealed, in general, that females are perceived as lacking the qualities for being good thieves (e.g., heart, trust), exhibit specific deficiencies which limit their actual or perceived ability to perpetrate crimes, and tend to be relegated to subservient roles if and when they are involved in mixed-sex crime activities unless special opportunities or circumstances exist in which a female partner is distinctly an advantage to the male for pulling off the crime. This institutionalized sexism in the underworld narrowly restricts the illegitimate opportunities available to females and helps explain why females are seldom involved in lucrative criminal enterprise. We conclude by suggesting: that the study of female criminality has been retarded by an inaccurate conception of crime as an isolated act committed by a person, without regard to that person's relationships with other people, groups, and organizations.

Living catalysts, complexes and polymers therefrom

Abstract: This invention provides a novel catalyst composed of a complex of an organic acid or its ester and a Lewis acid, preferably boron trichloride that can add olefin monomers to increase the molecular weight of the complex from as low as 200 to in excess of a million, with the complex being active viz., living, until the complex dies, viz., is decomposed or destroyed so that polymers in the liquid or easily liquefiable range of 300 to about 10,000 can be made of those more difficult to be liquefied or unliquefiable, viz., those of over 10,000 up to 100,000 or in some cases 500,000 and then those in the range of the elastomers, or moldable or extrudable plastics range having very high molecular weights, generally in excess of 100,000 up to in excess of 500,000 and having useful end groups such as the halogens and specifically chloride, allyl, acryl or methacryl, acetate or formate to name some of the more useful ones.

Free radical polymerization models for simulating reactive processing

Abstract: The generally accepted kinetic mechanism for free radical copolymerization was simplified by various assumptions and restrictions to give several realistic and easily evaluated models for the simulation of industrial molding. Six assumptions, including conversion-dependent rate coefficients and constant comonomer concentration ratios, were used to obtain a simplified model. Special cases of this simplified model were obtained by the following additional constraints: (1) Restriction C, consecutive inhibition and radical generation reactions; (2) Restriction I, constant initiator decomposition rate; (3) Restriction Z, zero termination rate for free radicals; and (4) Restriction K or P, all rate coefficients independent of conversion or only polymerization rate coefficient dependent on conversion. For various combinations of these restrictions, the time and concentration variables in the simplified model are separated and solved; the separate solutions are then combined in various ways to give models capable of predicting a wide variety of behavior. Many of these models have analytical solutions that greatly facilitate the evaluation of rate constants. Models based on restrictions KCI, PCI, and PCZ are shown to give good agreement with isothermal DSC data plotted as reaction rate versus time and, in a more sensitive test, as reaction rate divided by monomer concentration versus fractional conversion. Because of their predictive ability and ease of evaluating constants. Models PCI and PCZ are recommended for simulating industrial processing; they are particularly well suited for simulating compression molding of sheet molding compound.

Liquid crystal fiber-reinforced polymer composite and process for preparing same

Abstract: Novel self-reinforced polymer composites of a base polymer with a melt processable liquid crystal polymer are prepared according to this invention. The base polymer is a flexible chain polymer, e.g. a conventional thermoplastic. Polycarbonate is a particularly suitable base polymer. The liquid crystal polymer is melt processable, that is, it has a melting point and exhibits anisotropic properties in the melt phase. Wholly aromatic copolyesters are particularly suitable. Mixing is carried out at a temperature at which both the base polymer and the liquid crystal are melt processable, i.e., at a temperature at which the base polymer flows readily and the liquid crystal polymer is above its melting point. The products of this invention comprise about 2 to 20 percent by weight of liquid crystal polymer, which is in the form of essentially unidirectionally oriented continuous fibers primarily in the range of about 1 to 10 micrometers in diameter, distributed in a matrix of the base polymer. The polymer composites of this invention have high tensile strength in both the fiber direction and the transverse direction, and also have high modulus, satisfactory elongation, good impact strength, and good high temperature properties.

Structure and ultimate properties of epoxy resins

Abstract: Common epoxy thermosets are glassy at ambient temperatures and are characterized by a densely crosslinked microstructure. Under normal use conditions they generally fail by brittle fracture mechanisms. The influence of network microstructure on glassy fracture is largely undetermined in spite of a sizeable literature. This can be attributed to a lack of studies on structurally characterized networks and the often complicated microstructure of typical epoxy systems. To address these problems we examine structure-fracture relationships in simple epoxy systems whose structural variables are systematically controlled. Densely crosslinked networks may be characterized by equilibrium modulus measurements above Tg. Application of rubber elasticity theory yields very reasonable average network chain molecular weights (Mc); surprising in view of the expected non-Gaussian character of short epoxy network chains. Rubbery fracture energy increases with Mc when compared at equivalent temperatures above Tg. In fact, the dependence approximates a M c 1/2 ordering, suggesting that the influence of a threshold fracture energy persists well into nonthreshold testing conditions. Often, glassy fracture is characterized by brittle, unstable crack propagation leading to initiation and arrest fracture energies. The initiation values increase with temperature and generally increase with Mc. In comparison, the arrest values are independent of temperature and display a strong proportionality to M c 1/2 . A theory presuming material devitrification at a sharp crack tip is consistent with this observation.

Reliability of the Attitudes toward Women Scale

Abstract: This study investigated the reliability of the 55-item, 25-item, and 15-item, Attitudes Toward Women Scales. A sample of 43 female college students, their mothers, and their grandmothers was used i...

Cocrystallization and miscibility studies of blends of ultrahigh molecular weight polyethylene with conventional polyethylenes

Abstract: Ultrahigh molecular weight polyethylene (UHMWPE) was mechanically mixed with conventional polyethylenes (LLDPE, HDPE, and LLDPE) using an internal mixer. Rheological studies of these blends suggest that UHMWPE seems to be miscible with LLDPE, HDPE, and LDPE in the melt state. Yield characteristics are observed in all blend systems, particularly in high UHMWPE blend compositions. Differential scanning calorimetry and small-angle light scattering studies show that cocrystallization takes place in the blends of UHMWPE/LLDPE and UHMWPE/HDPE blends. However, separate crystals are formed in UHMWPE/LDPE. The formation of separate crystals may be attributed to long chain branching of conventional low-density polyethylene. Tensile properties of the former two blends vary almost linearly with blend compositions, while deviations are seen in the latter UHMWPE/LDPE blends.

Electrically actuated aircraft brakes

Abstract: This invention provides a roller screw drive mechanism (60) driven by an electric torque motor (50) through a gear drive (58,58',58") associated with either the screw (64,94) or nut (62,92) member of the roller screw drive mechanism. Rotation of the gear drive (58, 58', 58") by the torque motor (50) effectively moves the other member of the roller screw drive mechanism into axial engagement with the brake pressure plate (32) for braking action in response to an electrical control signal fed to the torque motor. A plurality of torque motor driven roller screw drive mechanisms are mounted in a balanced arrangement about the axis of the wheel and brake assembly to effectively apply and release a brake pressure force on the brake pressure plate in response to an electrical control signal to the torque motors.

The effect of recent life events stress, life assets, and temperament pattern on cardiovascular risk factors for Akron City police officers.

Abstract: Police officers, as a group, experience many occupational demands with physiological and psychological effects that could be harmful to their health. A primary objective of this study was to analyze specific behavioral and physiological risk factors that could lead to hypertension and accelerated coronary artery disease. Three hundred thirty-one male Akron City police officers participated in the study. A group of volunteer males (n = 48) who worked in city clerical jobs were used as controls. Questionnaires were administered in order to measure such behavioral variables as recent life change, life assets, and temperament pattern. Blood chemistry and physiological variables were also measured. The police officers had higher diastolic blood pressure (DBP), norepinephrine (NE) levels, and recent life change unit (LCU) scores than the control group. Increased hostility and depression scores were associated with higher DBP and recent LCU scores and lower life asset unit (LAU) scores. Individuals with...

Polyethylene-polycarbonate blends: Interface modification, phase morphology and measurement of orientation development during cast film and tubular extrusion by infrared dichroism

Abstract: The phase morphology and polymer chain orientation in polyethylene-polycarbonte blends is investigated. A blend with a dispersed polyethylene phase was found to exhibit phase growth under quiescent conditions. Addition of a styrene-(ethylene/butene) block copolymer controls the phase morphology and prevents phase growth. Melt spun tapes and tubular film have been prepared from polyethylene-polycarbonate blends. Orientation of the crystallo-graphic axes of the polyethylene and the chain axis of the polycarbonate were determined by infrared dichroism. The addition of polycarbonate to polyethylene is found to decrease chain orientation at the same drawdown stress.

Flow cytometric analysis of deparaffinized nuclei in urinary bladder carcinoma. Comparison with cytogenetic analysis

Abstract: Both cytogenetic analysis and flow cytometry (FCM) have prognostic efficacy in the analysis of transitional cell carcinoma (TCC) of urinary bladder. To correlate results of the two methods, we studied a unique group of patients whose tumors had undergone prospective conventional cytogenetic analysis. Paraffin blocks of these tumors were processed for FCM, then analyzed for nuclear DNA content. Of the 34 tumors processed, 30 (88%) yielded interpretable DNA histograms. In 26 (87%) of these, there was good correlation between the two methods with respect to the presence or absence of a hyperdiploid cell line. Discrepancies may have resulted from sampling error or from interpretation of a tetraploid peak as a prominent G2M region. Retrospective FCM analysis of paraffinized TCC tissue correlates well with conventional, prospective cytogenetic analysis and is applicable to the majority of urinary bladder transitional cell carcinomas. Cancer 57:1594–1601, 1986.

Crusading Journalism: Changing Public Attitudes and Policy-Making Agendas

Abstract: INVESTIGATIVE reporting is a costly and trendy enterprise used by publishers and broadcasters to build their audiences. Researchers studying mass media influence on the salience of issues before the public-their "agenda-setting" function-seldom have studied this controversial form of reporting. Nonetheless, agenda-setting research is growing, and with it the question of the strength of the causal relationship between media content and public opinion. The methodologies and the findings vary from study to study, with the agenda-setting effects demonstrated both in broadcast and print media. (See literature review by Roberts and Bachen, 1981.)

Excessive measures and Markov processes with random birth and death

Abstract: On utilise un processus markovien continu a droite stationnaire defini sur un intervalle de temps aleatoire, comme outil naturel pour developper plusieurs aspects de la theorie des mesures excessives

Composite insulated wall

Abstract: There is disclosed a reinforced, insulated concrete laminated wall. The central portion is a rigid insulation core through which vertical ladder structures extend transversely. Matched pairs of horizontal braces extend parallel to and abut the insulation core to hold it firmly in place. The horizontal braces rest on the rungs of the transverse vertical ladders and may be locked down on the rungs to prevent movement during concrete pouring. The wall is manufactured by positioning the core, ladders and braces medially between suitable forms. A single stage pour of concrete is then made to form the complete wall without resetting the forms. The wall may be constructed directly on a building foundation or prefabricated and subsequently positioned on the foundation.

Crystal structure of bis(2,4-pentanedionato)copper(II)

Abstract: The structure of bis(acetylacetonato)copper(II) has been redetermined from single crystal X-ray diffraction data The unit cell parameters area=11331(9),b=4697(3),c=10290(9) A, andβ=9184(7)dg A finalR=0056 for 727 observed reflections was obtained The O-Cu-O chelate (bite) angle is 932(2)° The two Cu-O bond lengths are 1914(4) and 1912(4) A The complex has a slight chair structure and a step angle of 705°

Pull-off forces for adhesive tapes

Abstract: : An analysis is given of the force F required to pull an adhesive tape of unit width away from a rigid substrate in terms of the strength G sub a of adhesion, the tensile modulus E of the tape, and its thickness t. Measurements are reported for several commercial adhesive tapes and compared with the predictions of the theory. Excellent agreement is obtained, suggesting that the theory is basically correct. Attention is drawn to the unusual form the dependence of the failure force F upon the work G sub a of detachment and the resistance Et of of the tape to stretching in this case: F(4) variation Et G sub a(3). Even though the tape is assumed to be linearly-elastic, the markedly non-linear (cubic) relation between force F and displacement delta of the tape away from the substratee leads to this unusual result. Differences observed in G sub a from pull-off and from 90 deg peeling experiments are tentatively attributed to additional energy losses in the latter case due to the severe bending deformations imposed on the tape as it is peeled away. Keywords: Detachment, Fracture energy, Fracture mechanics, Peeling, Separation, and Strength.

A Cautionary Note on the Use of Principal Components Analysis

Abstract: Principal components analysis and common factor analysis can provide similar results; however, to assume the results will be similar can lead to serious error. A simple example is provided to show how results can be substantially different.

Process for incorporating an additive into a polymer and product produced thereby

Abstract: A process is described for infusing an additive into a polymer using a compressed fluid that is normally a gas at room temperature and pressure. The additive must have some degree of solubility in the compressed fluid and the solution of compressed fluid and additive must have some degree of solubility in the polymer. In accordance with the process, the solution of the normally gaseous fluid and additive and the polymer are brought into contact under pressure until a desired quantity of the solution is absorbed into the polymer. The compressed fluid then is diffused from the polymer leaving additive infused within the polymer. The process can be used, for example, to add a colorant to a polymer or to add a biocide, insect repellant, medication or other additives to a polymer for subsequent sustained release, or to introduce monomer and a polymerization initiator into a polymer for subsequent polymerization.