THE EFFECT OF BOND STRENGTH OF FLEXIBLE LAMINATES ON PUNCTURE RESISTANCE

This work was aimed at understanding whether the bond strength of laminates will affect the puncture resistance of the laminate. Even though a strongly bonded adhesive layer in between two webs will considerably improve the mechanical properties of the laminate compared to that of the individual materials, there is a general belief in the packaging industry that having a lower bond strength helps to improve the bending or, in other words, the flexibility of the laminate thereby increases the tear and puncture resistance. Laminations of aluminum foil and polyethylene terephthalate (PET) were used as a model system to determine the validity of this industry paradigm. The variables used in this study were adhesive coating weight, adhesive system and additives used to control bond strength. The weight of coating was controlled to around 1.5 pounds per ream using different Meyer rods. Two popular polyurethane based adhesive systems, Tycel from Liofol¨ and Adcote¨ from Rohm and Haas were used with talc and microcrystalline polypropylene wax as additives. The additive loading was adjusted at 5%, 10%, 15% and 20% with respect to the total percent solids in the pure adhesive mixture. The cured, off-machine and time based values for adhesive bond strength and puncture resistance were measured. Two probes, ASTM probe and a hemispherical probe were used to measure the puncture resistance of the laminates from both PET and Foil sides. The off-machine bond strength for both the adhesive systems using talc and PP wax shows a gradual decrease in values. The cured laminates underwent material failure at low percentage loading of the additive up to 10 % as the cured bond strength values were higher than the strength of PET film. Above 10% additive loading, the bond strength values showed a quadratic decrease similar to off-machine bond strength values. However, the puncture strength of cured laminates did not show any corresponding change for different percent loading of additives. The ASTM probe gave higher puncture values than the hemispherical probe. The puncture strength showed a gradual increase over a time period of 4 to 4.5 hours. The trend is initially linear changing to a quadratic mode at longer time periods. It was also noted that the mode of puncture changed from multiple substrate failure with delamination to a single substrate failure with no appreciable delamination as curing time approached 4.5 hours showing that most of the curing process takes place in the initial 4 hours after lamination

Ferromagnetic Ligand Holes in Cobalt Perovskite Electrocatalysts as Essential Factor for High Activity Towards Oxygen Evolution

The definition of the interplay between chemical composition, electro-magnetic configuration and catalytic activity requires a rational study of the orbital physics behind active materials. Apart from Coulomb forces, quantum spin exchange interactions (QSEI) are part of the potentials that differentiate the activity of magnetic oxides, strongly correlated electrocatalysts, in electron transfer reactions. Ferromagnetic (FM) cobalt oxides can show low overpotentials for the oxygen evolution reaction (OER) and the La1XSrXCoO3d (0 r X r 1) family of perovskites is good ground to gain understanding of the electronic interactions in strongly correlated catalysts. In this case, Sr-doping raises the OER activity and the conductivity and increases FM spin moments. The efficiency of electrocatalysts based on Earth-abundant 3d-transition metals correlates with the interrelated factors: mild-bonding energies, the reduction of the electronic repulsions because of the QSEI in the open-shells, and enhanced spin delocalization in FM ordering. The reason for the outstanding OER activity of SrCoO3d is the accumulation of FM holes in the 3d–2p bonds, including the ligand orbitals, thus facilitating spinselected charge transport and production of triplet O2 moieties from the oxidation of diamagnetic precursors. Spin-polarized oxygen atoms in the lattice can participate in O–O coupling and release of O2 in a Mars–Van Krevelen mechanistic fashion. We show that the stabilizing FM QSEI decrease the adsorption and activation energies during oxygen evolution and spin-dependent potentials are one of the factors that govern the catalytic activity of magnetic compositions: spintro-catalysis

Psychosocial and physiological assessments of orthognathic patients

Aims: The primary aim was to compare, in the RoI, generic oral health-related quality of life (OHIP14), condition-specific quality of life (OQLQ), the fear of negative evaluation (BFNES) and self-reported BMI of patients seeking surgical-orthodontic correction of their malocclusion versus those of the general population. A secondary aim was to assess the IOFTN in the orthognathic cohort and to investigate any correlation between the functional domain of OQLQ and IOFTN. Materials and Methods: Orthognathic patients prior to commencing pre-surgical orthodontics from five regional HSE orthodontic units within the RoI and randomly selected age-matched subjects from the general population were invited to complete a telephone interview. Participants were asked questions regarding general characteristics and then asked to respond to the validated questionnaires OHIP-14, OQLQ, and BFNES. IOFTN grades of the orthognathic sample were also assessed. Results: Eighty orthognathic patients (39 males; 41 females) with an overall mean age of 17.5 (SD 1.6) years and 213 subjects from the general population (95 males; 118 females) with an overall mean age of 17.8 (SD 1.5) years completed a telephone interview. Orthognathic patients had significantly higher mean scores for OHIP-14, OQLQ and S-BFNES than the general population (p < 0.001). The mean score of OHIP-14 for the orthognathic patients and the general population were 14 (SD 8.6) and 5 (SD 5.9) respectively. Corresponding group scores for OQLQ were 40.9 (SD 19.3) and 19.9 (SD 14.9), and for S-BFNES were 23.2 (SD 7.2) and 18.8 (SD 8.1). Females had higher overall OQLQ and S-BFNES scores than males in both groups (p < 0.0001). There was no significant difference in the distribution of self-reported BMI categories between the groups (p = 0.8931). More than 90 per cent of the orthognathic sample were in IOFTN grade 4 and grade 5 showing ‘great’ and ‘very great’ functional need for surgery respectively. No association was found between the functional domain of OQLQ and IOFTN categories (p=0.5530). Conclusion: Orthognathic patients reported significantly poorer oral-health related and condition-specific quality of life as well as higher levels of social anxiety than the general population. Females in both groups had higher scores than males for OQLQ and S-BFNES. There was no correlation between the functional domain of OQLQ and IOFTN

Two Antifungal Agents From Streptomycetes

120 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1963.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

A brief review on the techniques used for the enhancement of luminescence of red emitting thin film

In the past few years, red emitting thin film activated by Eu3+ has received much attention. Europium has a peculiar property that it exhibits both types of emission on the basis of their valencies. In this review, we try to make a full list of known methods which may be useful for the enhancement of luminescence. It has been found that luminescence can be enhanced by increasing substrate temperature, film roughness, changing the morphology etc. Finally we discuss the mechanism of co-doping with different elements for the enhancement of luminescence

In situ ATR-FTIR studies on MgCl2-Diisobutyl phthalate interactions in thin film Ziegler-Natta catalysts

To study the surface structure of MgCl2 support and its interaction with other active components in Ziegler–Natta catalyst, such as electron donors, we prepared a thin film analogue for Ziegler–Natta ethylene polymerization catalyst support by spin-coating a solution of MgCl2 in ethanol, optionally containing a diester internal donor (diisobutyl-ortho-phthalate, DIBP) on a flat Si crystal surface. The donor content of these films was quantified by applying attenuated total internal reflection–Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). Changes in the interaction of DIBP with MgCl2 at various temperatures were monitored by in situ ATR-FTIR. Upon increasing the temperature, a shift in the (C-O) band toward lower wavenumbers was observed together with the depletion of (O–H) stretching band due to the desorption of residual ethanol. We assign this shift to gradual redistribution of adsorbed DIBP from adsorption sites on the MgCl2 (104) surface toward the more acidic MgCl2 (110) surface. The morphologies of MgCl2 and MgCl2/DIBP films were studied by transmission electron microscopy (TEM) revealing a preferential orientation of ClMgCl layers (001) parallel to the lateral film dimensions. This orientation becomes more pronounced upon annealing. In the absence of donor, the MgCl2 grow in to large crystals aligned in large domains upon annealing. Both crystal growth and alignment is impeded by the presence of donor

Secondary hypertension: A rare cause

A 13-year-old, previously asymptomatic girl was admitted with features of tuberculous meningitis. She was found to be hypertensive and further investigations revealed an extra-adrenal paraganglioma. Tuberculous meningitis and paraganglioma could be chance associations. Paraganglioma is a very rare and potentially lethal cause of secondary hypertension. We are reporting a very rare disease, which has come to light in a most unexpected manner