Leak-proof Heat Sealing of Press-Formed Paperboard Trays

Three-dimensional (3D) forming of paperboard and heat sealing of lidding films to trays manufactured by the press forming process are investigated in this thesis. The aim of the work was to investigate and recognize the factors affecting the quality of heat sealing and the leak resistance (tightness) of press-formed, polymer-coated paperboard trays heatsealed with a multi-layer polymer based lidding film. One target was to achieve a solution that can be used in food packaging using modified atmosphere packaging (MAP). The main challenge in acquiring adequate tightness properties for the use of MAP is creases in the sealing area of the paperboard trays which can act as capillary tubes and prevent leak-proof sealing. Several experiments were made to investigate the effect of different factors and process parameters in the forming and sealing processes. Also different methods of analysis, such as microscopic analysis and 3D-profilometry were used to investigate the structure of the creases in the sealing area, and to analyse the surface characteristics of the tray flange of the formed trays to define quality that can be sealed with satisfactory tightness for the use of MAP. The main factors and parameters that had an effect on the result of leak-proof sealing and must be adjusted accordingly were the tray geometry and dimensions, blank holding force in press forming, surface roughness of the sealing area, the geometry and depth of the creases, and the sealing pressure. The results show that the quality of press-formed, polymer-coated paperboard trays and multi-layer polymer lidding films can be satisfactory for the use of modified atmosphere packaging in food solutions. Suitable tools, materials, and process parameters have to be selected and used during the tray manufacturing process and lid sealing process, however. Utilizing these solutions and results makes it possible for a package that is made mostly from renewable and recyclable sources to be a considerable alternative for packages made completely from oil based polymers, and to achieve a greater market share for fibre-based solutions in food packaging using MAP.

The effect of pH and ethanol on the astringent sub-qualities of red wine, and the implications for optimum grape maturity /

The first objective of this study was to identify appropriate sensory descriptors to assess the astringent sub-qualities of red wine. The influence of pH and ethanol on the sensation of astringency in red wine was evaluated, using a de-alcoholized red wine. A portion of the wine was adjusted to the pH values of 3.2, 3.4, 3.6 and 3.8, and another portion was adjusted to ethanol concentrations of 0%, 6%, 12%, and 15%. In addition, the pH 3.4 and 3.6 treatments were adjusted to an ethanol concentration of 12% and 15% all wines were then assessed sensorially and seventeen terms were identified, through panel discussion, to describe the mouth-feel and taste qualities: velvet, aggressive, silk/satin, dry, fleshy, unripe, pucker viscosity, abrasive, heat, chewy, acidity, grippy/adhesive, bitter, balance, overall astringency, and mouth-coat. Descriptive analysis profiling techniques were used to train the panel and measure the intensity of these attributes. It was found that decreasing pH values (averaged across all ethanol concentrations) showed an increase in the overall astringency of the wine. The combined treatments of ethanol and pH, real wine parameters (pH 3.4 and 3.6; 12% and 15% ethanol) did not have an effect on the perception of the astringent sub-qualities of the wine. A time intensity study was also included using the pH and ethanol adjusted wines, which showed that as the ethanol level of the wines increased so did the time to maximum intensity. The second objective was to identify appropriate sensory descriptors to evaluate the influence of grape maturity and maceration technique (grape skin contact) on the astringency sub-qualities of red vinifera wines from Niagara. The grapes were harvested across two dates, representing an early harvest and a late harvest. A portion of the Cabernet Sauvignon grapes wine was divided into three maceration treatments of oneweek maceration, standard two-week maceration, three-week maceration, and MCM. Another portion of both the early and late harvest Cabernet Sauvignon grapes were chaptalized to yield a final ethanol concentration of 14.5%. The wines were assessed sensorially and thirteen terms were identified, through panel discussion, to describe the mouth-feel and taste qualities: carbon dioxide, pucker, acidity, silk/chamois, dusty/chalky/powdery, sandpaper, numbing, grippy/adhesive, dry, mouthcoat, bitter, balance and, overall astringency. Descriptive analysis techniques were used to train the panel and measure the intensity of these attributes. The data revealed few significant differences in the mouth-feel of the wines with respect to maturity; which included differences in overall astringency and balance. There were varietal differences between Cabernet Sauvignon, Cabernet Franc, and Pinot Noir and differences for Cabernet Sauvignon wines due to the length and manner of maceration and as a result of chaptalization. Statistical analysis revealed a more complex mouth-feel for the Pinot Noir wines; and an increase in the intensity of the astringent sub-qualities as a result of the addition of sugar to the wines. These findings have implications for how processing decisions, such as optimum grape maturity and vinification methods may affect red wine quality.

Prevalence of overweight and obesity in children from urban and rural Niagara

Purpose: The influence of environment in the development of overweight and obesity is an ongoing concern. This investigation examined the influence of urbanization on the rates of childhood overweight and obesity. Method: 2167 (1090M, 1077F) grade four children from 75 schools in Ontario's Niagara Region were sampled. A sophisticated algorithm overlaying electoral boundaries, population densities, and the knowledge of community members was used to classify schools into one of three location categories: urban {N= 1588), urban fringe {N= 379), and rural (A^= 234). Each subject was measured for: height, weight, and aerobic performance (Leger). Physical activity was evaluated with the self-report Participation Questionnaire (free-time and organized sport activities), and teacher's evaluations of student activity. Overweight (overweight and obesity combined) was measured both as a continuous (BMI) and categorical variable (BMI category), to evaluate the prevalence by location. A multivariate analysis was used to test for a suppression effect. Results: BMI and BMI category did not differ significantly by location or gender, and no evidence of a gender interaction existed. According to both a linear and logistic regression, physical activity or fitness levels did not suppress the influence of location on BMI and BMI category. Age, gender, free-time activity, organized sports, fitness level, and number of siblings, were all found to significantly influence overweight. Conclusions: It is plausible that the prevalence of overweight does not differ in urban and rural children from the Niagara Region. Further investigation is recommended, examining subjects by individual location of residence, in multiple regions throughout Ontario.

Warren, Rhode Island : l'évolution d'une petite communauté canadienne-française établie en Nouvelle-Angleterre, 1895-1910

Aux lendemains de la Guerre de Sécession, le petit centre manufacturier de Warren, dans l’État du Rhode Island, attira plusieurs immigrants canadiens-français en quête de travail. Ces derniers s’organiseront rapidement en établissant un réseau paroissial, en fondant plusieurs sociétés mutuelles et en multipliant les commerces prêts à desservir une clientèle francophone de plus en plus nombreuse. Les premiers stades de développement de la communauté (1888-1895) avaient déjà été observés par Jean Lamarre dans le cadre de son mémoire de maîtrise (1985). D’une part, le chercheur avait remarqué un phénomène graduel d’enracinement des paroissiens et, d’autre part, l’analyse de leur profil socio-économique indiquait qu’ils travaillaient majoritairement à la filature. Par cette étude, nous avons voulu revisiter cette communauté au moment où sa présence dans le paysage industriel et urbain de Warren apparaît consolidée. Grâce aux listes nominatives du recensement fédéral de 1910 et aux publications gouvernementales parues à la même époque, nous évaluons l’ampleur des changements socio-économiques transformant la communauté en l’espace d’une quinzaine d’années. L’observation du processus d’intégration des Canadiens français à l’environnement industriel est complétée par une analyse de l’apport des femmes et des enfants au ménage ouvrier. Les conclusions principales de cette étude démontrent que malgré l’attrait indéniable que représente encore et toujours le secteur manufacturier auprès de nombreux travailleurs, les Canadiens français jouissent en 1910 d’une qualité de vie généralement supérieure à celle qui caractérisait leurs débuts au sein de la localité. Leur situation socio-économique s’apparentera d’ailleurs davantage à celle des anglophones de Warren, Yankees et Irlandais, que de celle des représentants de la « nouvelle vague d’immigration » (Polonais, Italiens et Portugais).

Use of photoacoustic effect for the detection of phase transitions in liquid crystal mixtures

We report on a laser induced photoacoustic study of the nematic-to-isotropic transition in certain commercial nematic liquid crystal mixtures, namely BL001, BL002, BL032 and BL035. A simple analysis of the experimental data using the Rosencwaig–Gersho theory shows that the heat capacities of all these compounds exhibit a sharp peak as the temperature of the sample is varied across the transition region. Also, substantial differences in the photoacoustic signal amplitudes in nematic and isotropic phases have been noticed for all the mixtures. The increased light scattering property of the nematic phase may be the reason for the enhanced photoacoustic signal amplitude in this phase.

Use of photoacoustic effect for the detection of phase transitions in liquid crystal mixtures

We report on a laser induced photoacoustic study of the nematic-to-isotropic transition in certain commercial nematic liquid crystal mixtures, namely BL001, BL002, BL032 and BL035. A simple analysis of the experimental data using the Rosencwaig–Gersho theory shows that the heat capacities of all these compounds exhibit a sharp peak as the temperature of the sample is varied across the transition region. Also, substantial differences in the photoacoustic signal amplitudes in nematic and isotropic phases have been noticed for all the mixtures. The increased light scattering property of the nematic phase may be the reason for the enhanced photoacoustic signal amplitude in this phase

Use of photoacoustic effect for the detection of phase transitions in liquid crystal mixtures

We report on a laser induced photoacoustic study of the nematic-to-isotropic transition in certain commercial nematic liquid crystal mixtures, namely BL001, BL002, BL032 and BL035. A simple analysis of the experimental data using the Rosencwaig–Gersho theory shows that the heat capacities of all these compounds exhibit a sharp peak as the temperature of the sample is varied across the transition region. Also, substantial differences in the photoacoustic signal amplitudes in nematic and isotropic phases have been noticed for all the mixtures. The increased light scattering property of the nematic phase may be the reason for the enhanced photoacoustic signal amplitude in this phase.

Effect of Te doping on thermal diffusivity of Bi2Se3 crystals: A study using open cell photoacoustic technique

An open cell configuration has been employed for the photoacoustic measurement of the thermal diffusivity of undoped Bi2Se3 crystals and Bi2Se3 crystals doped with various concentrations of Te. The amplitude of the photoacoustic signal obtained under heat transmission configuration as a function of chopping frequency is used to evaluate the numerical value of thermal diffusivity, α. Doped samples show a substantial reduction in the value of α compared to undoped samples. The variations in the thermal diffusivity of the doped samples are explained in terms of the phonon assisted heat transfer mechanism. It is seen that α is very sensitive to structural variations arising from doping. The experimentally observed results are correlated with X-ray diffraction studies.

Photoacoustic study of the effect of doping concentration on the transport properties of GaAs epitaxial layers

We report a photoacoustic (PA) study of the thermal and transport properties of a GaAs epitaxial layer doped with Si at varying doping concentration, grown on GaAs substrate by molecular beam epitaxy. The data are analyzed on the basis of Rosencwaig and Gersho’s theory of the PA effect. The amplitude of the PA signal gives information about various heat generation mechanisms in semiconductors. The experimental data obtained from the measurement of the PA signal as a function of modulation frequency in a heat transmission configuration were fitted with the phase of PA signal obtained from the theoretical model evaluated by considering four parameters—viz., thermal diffusivity, diffusion coefficient, nonradiative recombination time, and surface recombination velocity—as adjustable parameters. It is seen from the analysis that the photoacoustic technique is sensitive to the changes in the surface states depend on the doping concentration. The study demonstrates the effectiveness of the photoacoustic technique as a noninvasive and nondestructive method to measure and evaluate the thermal and transport properties of epitaxial layers.

Studies on Heat Diffusion in Selected Conducting Polymers using Probe Beam Deflection and Photoacoustic Techniques

In the present study, radio frequency plasma polymerization technique is used to prepare thin films of polyaniline, polypyrrole, poly N-methyl pyrrole and polythiophene. The thermal characterization of these films is carried out using transverse probe beam deflection method. Electrical conductivity and band gaps are also determined. The effect of iodine doping on electrical conductivity and the rate of heat diffusion is explored.Bulk samples of poyaniline and polypyrrole in powder form are synthesized by chemical route. Open photoacoustic cell configuration is employed for the thermal characterization of these samples. The effect of acid doping on heat diffusion in these bulk samples of polyaniline is also investigated. The variation of electrical conductivity of doped polyaniline and polypyrrole with temperature is also studied for drawing conclusion on the nature of conduction in these samples. In order to improve the processability of polyaniline and polypyrrole, these polymers are incorporated into a host matrix of poly vinyl chloride. Measurements of thermal diffusivity and electrical conductivity of these samples are carried out to investigate the variation of these quantities as a function of the content of polyvinyl chloride.

Studies on the effect of the organophosphorus pesticide Eka(Rlu) x EC 25 on the bacterial flora of Villorita cyprinoides var. cochinensis (Han1ey)

The thesis is Studies on the Effect or the Obganophosphorus Pesticide Ekalux(R) EC 25 on the Bacterial Flora or Villorita Cyprinoides Var.Cochinensis (Hanley). For the present investigation, the black clam Villorita gyprinoides var. cochinensis (Hanley), a most common clam genus present in this estuarine system has been selected as test organaism and Ekalux (R) EC 25 as toxicant. The aspects dealt with are 1. Total heterotrophic bacterial population, 2. Generic composition, 3. Hydrolytic enzyme producing bacteria, 4. Antibiotic resistance, 5. Heavy metal resistance, 6. The effect of pesticide concentration on the growth of the bacteria and 7. Effect of temperature, pH and sodium chloride on the growth and phosphate release of selected isolates.The samples for the experiment were collected from the Vembanad Lake, near Kumbalam Island during the period of September 1985 to May '86. The THB of the estuarine water and clams contained 6.5 x I04/ml and 2.975 x l06/g respectively, immediately after collection. Untreated water and clam samples showed enormous increase in THB from 0 hr population. The treated samples (water and clams) contained higher THB than 0 hr. In general, THB was observed to increase tremendously in the samples treated with pesticide when compared to their native flora. With reference to various concentrations of pesticides, THB recorded an increase with increase of concentration in water and clam samples.

Studies on the effect of pollution, with special reference to benthos, in Cochin backwaters

Considerable number of factories and related establishments forming an industrial complex are located in the upper reaches of the estuary from Varapuzha about 10km from cochin barmouth to Alwaye while lower down are the retting grounds at Vaduthala and nearby places at about 5km from the barmouth. Muncipal wastes from the city population of over 5 lakhs effluents and solid waste from several fish processing factories and other land washings around Willington island reach the estuary move near its lower reaches close to the barmouth. Cochin estuary is the biggest in the state providing water front for the largest number of industries from the small retting grounds of Vaduthala to the huge fertilizer factories of Udyogamandal and receiving the highest quantity of town sewage and land drainage. The estuary contributes itself as nursery ground for shrimps and related fishery as well. Study of this estuary therefore contributes to a typical environment as regards to pollution problems in the tropics and hence the scope of the present investigation

Effect of Feeding Rate in Polymer Extrusion ”

Starve feeding of single screw extruder was described as an important means of improving the performance characteristics of the extruder. In addition to such improvement with versatility, the starve feeding technique also may affect the mechanical properties of the extrudate since the heat transfer an(l mixing characteristics in the starve fed and Hood fed extruders are not the same. Since the material is more loosely packed in the channels of the starve fed extruder, there may be greater bed mobility and uniformity. Further, the. thermal an(l shear induced degradation are also less since possibilities of developing local high temperatures are less compared to a densely compacted extruder bed. This study has been undertaken mainly to explore the effect of feeding rate on the mechanical properties of rubber and plastic extrudates since the effect of feeding rate has not been analysed from this angle so far.

Effect of thermal annealing on Fe40Ni38B18Mo4 thin films: modified Herzer model for magnetic evolution

Magnetic properties of nano-crystalline soft magnetic alloys have usually been correlated to structural evolution with heat treatment. However, literature reports pertaining to the study of nano-crystalline thin films are less abundant. Thin films of Fe40Ni38B18Mo4 were deposited on glass substrates under a high vacuum of ≈ 10−6 Torr by employing resistive heating. They were annealed at various temperatures ranging from 373 to 773K based on differential scanning calorimetric studies carried out on the ribbons. The magnetic characteristics were investigated using vibrating sample magnetometry. Morphological characterizations were carried out using atomic force microscopy (AFM), and magnetic force microscopy (MFM) imaging is used to study the domain characteristics. The variation of magnetic properties with thermal annealing is also investigated. From AFM and MFM images it can be inferred that the crystallization temperature of the as-prepared films are lower than their bulk counterparts. Also there is a progressive evolution of coercivity up to 573 K, which is an indication of the lowering of nano-crystallization temperature in thin films. The variation of coercivity with the structural evolution of the thin films with annealing is discussed and a plausible explanation is provided using the modified random anisotropy model

The Effect of Antimony Substitution on the Magnetic and Structural Properties of Fe0.75–xSi0.25Sbx Alloys

The results of the investigation of the magnetic and structural properties of the alloy system Fe0.75–xSi0.25Sbx, where x = 0, 0.05, 0.1, 0.15, 0.2, and 0.25 synthesized by mechanical alloying followed by heat treatment are described. The x-ray diffraction reveals that all samples crystallize in the DO3-type cubic phase structure. Substituting Fe by Sb led to a de-crease in the lattice constant and the unit cell volume. The magnetic properties are investigated by vibrating sample magnetometer and show that all the samples are ferromagnetically ordered at room temperature. The Curie temperature is found to decrease linearly from (850 ± 5) K for the parent alloy to (620 ± 5) K for the alloyith x = 0.25. The satura-tion magnetizations at room temperature and at 100 K are found to decrease with increasing the antimony concentration. The above results indicate that Sb dissolves in the cubic structure of this alloy system.