The Effect of Business Intelligence on Innovation, Network Learning and Startup Performance (Case Study: Snapfood)

The study aimed to determine the effect of business intelligence on innovation, network learning, and startup performance. The research method is applied in terms of purpose, and in terms of collecting data, a descriptive correlational type is used. The statistical population of the study was four hundred employees in the city of Tehran, which according to the Cochran formula, 196 people were selected as the sample and the data collection tool was a questionnaire. The collected data were analyzed using LISREL software. The research results indicate that among the research variables, business intelligence, network learning, and innovation have the highest correlation coefficient with the startup function. Also, the results of the structural equation model indicate that the direct effect of business intelligence on network learning is positive and significant

Single-chain flexibility and conformation in polyarylates

This paper describes the use of molecular modeling was used to study the flexibility and conformation of single-chain sections of three polyarylates based on terephthalic acid and (i) bisphenol A, (ii) bisphenol based on methyl isobutyl ketone, and (iii) phenolphthalein. Configurational entropies were calculated based on the ease of rotation of various bonds. Entropies calculated for the cooperative rotation of the bisphenol phenyl rings did not correlate with the experimentally determined glass transition temperatures. However, a correlation was found using entropies determined for the independent rotation of various bonds keeping others in their minimum-energy conformation. The relative bond flexibilities can be normalized by comparing the configurational entropy in each case against that of a hypothetical freely rotating bond. These results may be useful in interpreting the gas diffusivity and thermal and mechanical properties of these polyarylates

Dynamic mechanical analysis and interpretation of molecular motions in polyarylates

Molecular motions in polyarylates synthesized from substituted bisphenols have been investigated by dynamic mechanical analysis. Substitution at the ring carbon atom results in a more pronounced enhancement in glass transition temperature (Tg) as compared to substitution at the bridge carbon atom. The enhancement in mono and disubstituted polyarylates is more consistent than that in the case of polycarbonates and polysulfones. The β transition has been shown to result from defects in the polymer samples. The molecular motion responsible for the τ transition in polyarylates has been shown to be more iocalized than in the case of polycarbonates. Introduction of the phthalide ring in the isopropylidene unit of bisphenol-A molecule results in splitting of the τ transition peak into two. The results have been compared with those reported for other bisphenol-based polymers, viz. polycarbonates and polysulfones, and explained on the basis of the structural attributes of the polymers

Transport of gases in aromatic polyesters: correlation with WAXD studies

Polymer packing density can be conveniently measured by either density-based measurements (direct or estimated free volume) or wide-angle X-ray diffraction (WAXD) spectra. Previously reported diffusivity and permeability values for various polyarylates and polyimides are examined on the basis of the packing density measured by these different techniques. It is shown that in these rigid glassy polymers, the mean intersegmental distance, the d-spacing, obtained from WAXD provides a better measure of the effect of polymer packing on diffusivity than either direct density measurements or estimated free volumes. It has been possible to correlate previously reported diffusivity and sorption data for various polyarylates and polycarbonate on the basis of the WAXD investigation, using the d-spacing and the amorphous peak width, respectively. The effect of polyarylate structure on d-spacing has been studied. A series of polyarylates have been synthesized with different substituents on the bridge carbon. In this series the d-spacing remains constant while the carbonyl group density and the glass transition temperatures are varied. However, small substituents on the aromatic ring cause significant changes in the d-spacing. These results can be used to tailor polyarylates with desired intersegmental distances and chain flexibility

Gas permeation in polyarylates: effects of polarity and intersegmental mobility

Permeability coefficients for He, Ar, O2, N2, CH4, and CO2 in five polyarylates synthesized from a mixture of iso: terephthalic acids (1:1) and a bridge substituted bisphenol were measured at a pressure of 1.0 × 106 N/m2 and temperature of 35°C. Bisphenols used for the syntheses of these polyarylates were prepared by substituting one of the bridge methyl groups (-CH3) in bisphenol-A with one of the following functional groups: ethyl (-CH2-CH3), isobutyl (-CH2-CH(CH3)2), phenyl (-C6H5), or methyl propionate (-CH2-CH2-COOCH3). This type of substitution does not affect the polymer packing significantly. The calculated Hildebrand solubility parameter for these polyarylates also varies only in a narrow range. With these critical parameters being constant, the polyarylate permeabilities correlate well with increasing chain stiffness as indicated by secondary transition temperatures (Tτ°C). Substitutions which increased polarity had a negative effect on transport properties

Gas permeation in polyarylates: effect of bisphenol and acid substitution symmetry

The effect of bisphenol substitution symmetry on gas permeation as well as other relevant structural properties of polyarylates has been investigated both experimentally and by molecular modelling. Asymmetric or di-substitution of methyl groups on the phenyl rings of bisphenol-A or phenolphthalein resulted in polyarylates with similar packing density and permeability and with increased permselectivity compared to the corresponding polymers with the unsubstituted bisphenols. Symmetric or tetra-substitution of methyl groups on the bisphenol-A phenyl rings led to polyarylates with decreased packing density, increased permeability and similar selectivities as the corresponding polymers with the unsubstituted bisphenol. Molecular modelling studies of the chain conformation gave further insight into the mechanism by which substitution symmetry affects the polymer properties. The differences in the minimum energy chain conformation of symmetrically and asymmetrically substituted bisphenol-A polyarylate chains help in explaining the variation in packing density and permeation properties. Calculations of relative bond flexibility and the energy barrier for bond rotation of specific moieties in the minimized energy chain conformation correlate with molecular mobility as measured by sub-Tg transition temperatures. The diacid used for polyarylate synthesis was also varied in order to investigate the effect of acid linkage symmetry. Polyarylates based on the above bisphenols and asymmetrically linked isophthalic acid were compared with the corresponding polymers based on symmetrically linked terephthalic acid or 2,6-naphthalene dicarboxylic acid. Isophthalic acid-based polyarylates had higher packing density, chain mobility, and permselectivity and lower permeability than their terephthalic acid-based counterparts. Incorporation of the naphthalene acid along with the terephthalic acid also results in polyarylates with lower packing density and higher chain rigidity than the isophthalic acid-based polymers