Morley, S. A. (1998). Environmental and parental influences on the size of herring larvae. Ph.D. thesis submitted to the University of Liverpool for the degree of Doctor of Philosophy Investigations were carried out into the effects of mean egg dry weight and incubation temperature on the size of larvae from four N.E. Atlantic herring stocks (Buchan, Manx, Clyde and Celtic Sea). Hatching characterisitics (length, weight and yolk volume) of Buchan, Manx and Clyde herring were investigated. The time of hatching was inversely related to incubation temperature, although there was some variation between experiments in the date of peak hatching. The total length of larvae increased through the hatching period. In all experiments mean egg dry weight per female was strongly related to the average length, weight and yolk volume of larvae at hatching. The same regression model could be applied to all stocks. There were, however, stock-specific responses of hatching characteristics to incubation temperature although a reduction in length at hatching at higher temperatures was the most consistent response. Development at low temperature resulted in a modification of the length-weight relationship; larvae of the same weight were longer at lower temperatures. Both the increase in length of larvae during the hatching period and the variation in the timing of peak hatching have implications for the comparison of larvae hatching at different temperatures. The otoliths of Manx herring larvae [from "large" (> 0.33mg mean dry weight) and "small" «0.2Smg mean dry weight) eggs] were marked with either alizarin complexone or calcein so that larvae from pairs of large and small egg batches could be reared under identical conditions (at both 10 and I3.S0C) and relative growth monitored. Within each rearing tank large eggs generally produced larger larvae at hatch (length and weight) with higher growth rates (both weight and length specific). There were significant differences both between eggs from different females and between rearing tanks that confounded the comparisons between rearing temperatures. Fultons Condition factor is not thought to be a good measure of nutritional condition of herring larvae smaller than ISmm total length but may be used as a relative measure of body reserves (ReF) and give an indication of ability to withstand periods of poor feeding. This is indicated by a period of high mortality of larvae hatched from small eggs at 10°C, which corresponded with the time period when these larvae had the lowest body reserves. Video recording of the foraging behaviour of laboratory reared herring larvae was used to investigate differences between the feeding strategies of groups of larvae of the same size but different ages, i.e. fast and slow growers. Slow growing larvae searched larger areas, thus expending more energy, than fast growing larvae, but there was no difference in food acquisition. The difference in behaviour tended to increase through development A simple energetics calculation suggested that approximately 50% of the difference in growth rate could be explained by the extra swimming costs of slower growing larvae. The size of Celtic Sea and Manx herring eggs were experimentally reduced in order to investigate if the volume of yolk in each egg determines the size of hatching larvae. Length at hatch was determined by the volume of yolk in each egg but body weight was not. The development and chemical composition of embryos and larvae needs to be investigated in a further series of experiments. All results are discussed in terms of the influence of larval size on survival.

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The elemental composition within structured insect populations was tested by creating a new method to analyze how variables (survival, growth and fecundity) within a population matrix could potentially affect the stoichiometric regime of a structured population at steady state. This was done by focusing on if the growth rate hypothesis, which states that there is a linear relationship between an individual growth rate and the percent of phosphorus within the individual, works at a population level. This was analyzed by creating and combining two matrices: the matrix-population containing the variables and a matrix containing the element phosphorus and dry weight. Data from a beetle species, Chrysomela tremulae F., was used as a guideline to create eight stoichiometric generic populations, where survival, growth and fecundity were tested in each of the eight generic populations. The results showed deviations from the growth rate hypothesis, suggesting that the hypothesis does not always work within structured populations. However, more research is needed to predict exactly how this hypothesis works in populations. Overall, this new method for analyzing stoichiometry within structured populations is a useful analytical tool, but there is a need for analyzing the results from these models in a more efficient way.

Lactose is the major carbohydrate in milk. The presence of lactose in whey constitutes a significant pollution problem for dairy factories. At the same time, there is an increasing market for high quality crystalline lactose. The main problem of lactose crystallisation, compared to sucrose, which is also a disaccharide, is that it is very slow, unpredictable and cannot easily be controlled. Compared to sucrose crystallisation, which has been extensively studied, lactose crystallisation lacks the fundamental research to identify the mechanisms of growth and effect of additives. An important difference from most other crystal growth systems is that ([alpha]-lactose hydrate crystals never grow from a pure environment; their growth environment always contains beta lactose. [alpha]-lactose monohydrate crystallises much more slowly because of the presence of [beta]- lactose in all solutions. Although there have been some studies on growth rates and the effect of additives, there has not been any reported work on the fundamentals of lactose crystallisation and the mechanisms that operate on the molecular level. The aim of this thesis is to gain a greater understanding at the fundamental processes, which occur at the molecular level during the crystallisation of lactose, in order to improve control at a macroscopic level. / The growth rates of the dominant crystallographic faces have been measured in situ, at three temperatures and over a wide range of supersaturation. The mean growth rates of faces were proportional to the power of between 2.5-3.1 of the relative supersaturation. The rate constants and the activation energies were calculated for four faces. The [alpha]-lactose monohydrate crystals grown in aqueous solutions exhibited growth rate dispersion. Crystals of similar size displayed almost 10 fold difference in the growth rate grown under identical conditions for all the faces. Growth rate dispersion increases with increasing growth rate and supersaturation for all the faces. The variance in the GRD for the (0 10) face is twice the variance of the GRD of the (110) and (100) faces and ten times higher than the (0 11) face at different supersaturations and temperatures. The influence of [beta]-lactose on the morphology of [alpha]-lactose monohydrate crystals has been investigated by crystallising [alpha]-lactose monohydrate from supersaturated DMSO ethanol solutions. The slowness of mutarotation in DMSO allowed preparation of saturated solutions with a fixed, chosen [beta]-lactose content. It was found that [beta]-lactose significantly influences the morphology of [alpha]- lactose monohydrate crystals grown from DMSO solution. At low concentrations of [beta]-lactose, the fastest growing face is the (011) face resulting in long thin prismatic crystals. At higher [beta]-lactose concentrations, the main growth occurs in the b direction and the (020) face becomes the fastest growing face (since the (011) face is blocked by [beta]-lactose), producing pyramid and tomahawk shaped crystals. / Molecular modeling was used to calculate morphologies of lactose crystals, thereby defining the surface energies of specific faces, and to calculate the energies of interactions between these faces and [beta]-lactose molecules. It was found that as the replacement energy of [beta]-lactose increased, the likelihood of [beta]-lactose to dock onto faces decreased and therefore the growth rate increased. The attachment energy of a new layer of [alpha]-lactose monohydrate to the faces containing [beta]-lactose was calculated for the (010) and (011) faces. For the (0 10) face, the attachment energy of a new layer was found to be lower than the attachment energy onto a pure lactose surface, meaning slower growth rates when [beta]-lactose was incorporated into the surface. For the (011) face, attachment energy calculations failed to predict the slower growth rates of this face in the presence of [beta]-lactose. AFM investigation of [alpha]-lactose monohydrate crystals produced very useful information about the surface characteristics of the different faces of the [alpha]-lactose monohydrate crystal. The growth of the (010) face of the crystal occurs by the lateral addition of growth layers. Steps are 2 nm high (unit cell height in the b direction) and emanate from double spirals, which usually occurred at the centre of the face. Double spirals rotate clockwise on the (010) face, while the direction of spirals is counterclockwise on the (010) face. A polygonised double spiral, showing anisotropy in the velocity of stepswas observed at the centre of the prism-shaped a-lactose monohydrate crystals grown in the presence of 5 and 10 % [beta]-lactose. / The mean spacing of the steps parallel to the (011) face is larger than those parallel to the (100) face, indicating higher growth rates of the (011 )face. The edge free energy of the (011) face is 6.6 times larger than the (100) face in the presence of 5% [beta]-lactose. Increase of [beta]-lactose content from 5% to 10 % decreases the edge free energy of the growth unit on a step parallel to the (011) face by 10 %. Tomahawk-shaped [alpha]-lactose monohydrate crystals produced from aqueous solutions where the [beta]-lactose content of the growth solution is about 60 % have shown clockwise double spirals as the source of unit cell high steps on the (010) face of the crystal. However , the spirals are more circular than polygonised, unlike the prism shaped crystals and the mean step spacing of the (011) face is less than the steps parallel to the (110) face, indicating the growth rate reducing effect of [beta]-lactose on the (011) face. The (100) face of the [alpha]-lactose monohydrate crystal grows by step advancement in relative supersaturations of up to 3.1. Steps are 0.8 nm high and parallel to the c rection. Above this supersaturation, rectangular shaped two-dimensional nuclei, 10 nm high, were observed. The (011) face of the crystal grown at low supersaturations (s= 2.1) displayed a very rough surface with no steps, covered by 4-10nm high and 100-200[micro]m wide formations. Triangular shaped macrosteps were observed when the crystal was grown in solutions with s=3.1. In situ AFM investigation of the (010) face (T = 20[degree]C and s = 1.18) has shown that growth occurs by lateral addition of growth units into steps emanated by double spirals. / The growth rate of the (010) face from in situ AFM growth experiments was calculated to be 1.25 gm/min. The growth rate of crystals grown in the in situ optical growth cell under identical conditions was 0.69 pm/min. The difference in growth rates can be attributed to the size difference of seed c stals used. The (010) face of a [alpha]-lactosemonohydrate crystal grown at 22.4 C and s=1.31 displayed triangular-shaped growth fronts parallel to the (011) face. The steps parallel to the (O11) face grow in a triangular shape, and spaces between triangles are filled by growth units until the end of the macrosteps is reached. No such formations were observed on steps parallel to the (110) face. Formation of macrosteps, 4-6 nm high, emanating from another spiral present on the surface was also observed on the (010) face of a crystal grown under these conditions.

A small amount of poly(trimethylene succinate) (PTSu) were copolymerized or blended with poly(butylenes succinate) (PBSu) in this study. The range of intrinsic viscosity for PBSu and PBSu-enriched copolymers are between 1.62 and 0.97 dL/g; number-average molecular weights are in the range of 2.5x104 and 11.9x104 g/mol with polydispersity indices ranging from 1.52 to 3.94. Copolymer composition is calculated from 1H and 13C NMR spectra, and the distribution of BS and TS units in these copolymers are supported to be random from the evidence of a single glass transition temperature (Tg) and a randomness value close to 1.0. Tg of PBSu is -40.8 ¢XC. The Tg values of copolymers and blends increased with TS contents. The melting temperature (Tm) and the exothermic heat of crystallization of blends were not strongly affected by blending with PTSu. The values of Avrami exponent (n) for PBSu, copolymers and blends ranging from 2.3 to 3.1 indicate that heterogeneous nucleation with three-dimensional growth and homogeneous nucleation with two-dimensional growth might happen during the crystallization process. Multiple melting behavior was observed for PBSu, PBSu- enriched copolyesters and blends. Their peak temperatures are denoted as Tm1, Tm2 and Tm3 in order of increasing temperature. Tm1 corresponds to the melting temperature of the so-called annealing peak which might be resulted from the competition between continuous melting and re-crystallization. In contrast the peak at Tm2 is attributed to the melting of the primary crystals formed during isothermal crystallization. The peak at Tm3 may arise from the melting of re-crystallized primary crystals. Equilibrium melting temperatures were determined by the Hoffman-Weeks linear extrapolations which yield of 127.4 ¢XC for PBS, 125.7 ¢XC for PBTSA95/05, 120.6 ¢XC for PBTSu90/10, 128.6 ¢XC for PBSu/PTSu 98/02, 127.0 ¢XC for PBSu/PTSu 95/05 and 125.5 ¢XC for PBSu/PTSu 90/10. The thickness coefficient ( ) is located between 0.77 and 0.80. Three characteristics temperatures of thermal degradation, defined as temperature of thermal degradation at begining (Tstart), weight losses of 2% (Tloss2%) and maximum degradation rate (Tmax), were employed to characterize the thermal stability of polyesters and blends. The Tloss2% and Tstart values of PBTSu90/10 are higher than the values of the others because of its unusually high molecular weight. Wide-angle x-ray diffraction patterns were obtained after complete isothermal crystallization. Diffraction peaks are in the same positions, and these peaks become sharper and increase in intensity as the crystallization temperature increases. This indicates that during the heating process, only one crystal form appears and both of the crystallite size and perfect degree increase. The isothermal growth rate of PBSu spherulite increases from 0.01 £gm/sec at 103 ¢XC to 3.33 £gm/sec at 75 ¢XC. When the TS units increase, the spherulitic growth rates of PBTSu95/05 and PBTSu90/10 copolyesters decline dramatically. One of the reasons is that the incorporation of TS units into PBSu significantly inhibits the crystallization behavior of PBSu. Growth rates data were treated with Lauritzen-Hoffman secondary nucleation theory to find the regime transition. Using the Williams-Landel-Ferry (WLF) values, regime II to III transition is found at 95.1 ¢XC for PBSu, 84.4 ¢XC PBTSu95/05, and 77.1 ¢XC for PBTSu 90/10. All melt-crystallized specimens formed two dimensional axial-like spherulites with negative birefringence. Extinction bands were observed when PBSu, PBSu- enriched copolymers and blends specimens were crystallized at large undercooling.

Minor amounts of monomers or homopolymer of poly(butylene succinate) (PBS) were copolymerized or blended with monomers or homopolymer of poly(ethylene succinate) (PES). PEBSA 95/05 represents a copolymer synthesized from a feed ratio of 95 mol% ethylene glycol and 5 mol% 1,4-butanediol with 100 mol% succinic acid. Copolymers PEBSA 90/10 and 50/50 were also synthesized. Blends of PES and PBS were prepared in solution with ratios of PES/PBS: 98/02, 95/05 and 90/10. Molecular weights of homopolymers and copolymers were measured using capillary viscometer and gel permeation chromatography. The results indicate that polyesters used in this study have high molecular weights. The chemical composition and the sequence distribution of co-monomers in copolyesters were determined using 1H NMR and 13C NMR. The distribution of ES and BS units in these copolyesters was found to be random from the evidence of a single Tg and a randomness value close to 1.0 for a random copolymer. Thermal properties of polyesters and blends were characterized using differential scanning calorimeter (DSC), temperature-modulated DSC (TMDSC) and thermogravimeter. For copolymers, melting point of PES significantly decreases from 100.9 to 94.5 to 89.8 oC with an increasing in BS units from 0 to 5 to 10 mol%. Blends keep the intrinsic melting points of PES and PBS homopolymers. There is no significant difference or no trend about the thermal stability of these polyesters and blends. Wide-angle X-ray diffractograms (WAXD) were obtained for specimens after complete isothermal crystallization. Diffraction peaks indicate that the crystal structure of PES is dominated in PES-enriched copolymers. However, PEBSA 50/50 displays weak diffraction peaks of the characteristic peaks of PBS homopolymer. Isothermal crystallization of copolyesters and blends were performed using DSC. Their crystallization kinetics and melting behavior after complete crystallization were analyzed. The n1 values of the Avrami exponent for copolyesters increased from 2.54 to 2.84 as the isothermal temperature (Tc) increased. The Hoffman-Weeks linear plots yielded an equilibrium melting temperature of 111.1 and 107.0 oC, respectively, for PEBSA 95/05 and 90/10. Homopolymer PES has an equilibrium melting temperature of 112.7 oC. For blends, the n1 value has a minimum at Tc of 40 oC then it increases with an increase in Tc or in PBS. At the same Tc, n1 increases slightly and the rate constant (k1) decreases when the ratio of PBS in blends increases. All of these blends gave an equilibrium melting temperature of 113.1 oC. Multiple melting behavior involves melting-recrystallization-remelting and various lamellar crystals. As Tc or BS unit in copolymer increases, the contribution of recrystallization slowly declines. Acetophenone was used a diluent for PES homopolymer. Five concentrations were used to estimate the melting point depression, and the heat of fusion of PES was obtained to have a value of 163.3 J/g according to Flory equation. Spherulitic growth rates of copolymers were measured at Tc between 30 and 80 oC using polarized light microscope (PLM). Maximum growth rates occurred at Tc around 50 oC. It is found that the growth rate of copolymer decreases significantly after randomly incorporating BS units into PES. Non-isothermal method at a cooling rate of 2, 4 or 6 oC/min was used to calculate the isothermal growth rates of copolymers. These continuous data fit very well with the data points measured isothermally. Growth rates data are separately analyzed using the Hoffman-Lauritzen equation. A regime II-III transition is found at 59.4 and 52.4 oC, respectively, for copolyesters PEBSA 95/05 and PEBSA 90/10. The results of DSC and PLM indicate that blend PES/PBS 98/02 not only retains the melting point and the crystallinity of PES homopolymer, but also increases the nucleation rate of this blend. The effect of blending 2 mol% PBS with PES on the biodegradability of PES is deserved to be investigated furthermore.

The topics of this study are as follows: (a) Poly(butylene succinate) (PBSu) rich random copolymers containing ~20% and ~50% trimethylene succinate (TS), PBTSu 80/20 and PBTSu 50/50 that were synthesized from 1,4-butanediol, 1,3-propanediol and succinic acid: The influence of minor TS units on the thermal properties and crystallization rate of PBSu was investigated. (b) Random copolymer of ~90% PBSu and ~10% poly(1,4-cyclohexanedimethylene succinate), PBCHDMSu 90/10, that was synthesized from 1,4-butanediol, 1,4-cyclohexanedimethanol and succinic acid: The influence of cyclohexene unit on the thermal properties and crystallization rate of PBSu was investigated. (c) Blends of PBSu and poly(trimethylene succinate) (PTSu) or poly(ethylene succinate) (PESu): The weight ratio PBSu and PTSu (or PESu ) were 1:1. The crystallization and morphology of blends (PBSu/PTSu 50/50 and PBSu/PESu 50/50) were investigated and compared with PBTSu 50 and PBESu 50/50. The chemical composition and the sequence distribution of co-monomers in copolyesters were determined using NMR. Thermal properties of polyesters and blends were characterized using differential scanning calorimeter (DSC) and temperature-modulated DSC (TMDSC). The crystallization kinetics and equilibrium melting temperature were analyzed with Avrami equation and Hoffman-Weeks linear extrapolation. The thermal stability of polyesters was analyzed by thermogravimeter (TGA) and polarized light microscope (PLM) under nitrogen. Wide-angle X-ray diffractograms (WAXD) were obtained for specimens after complete isothermal crystallization. The growth rates, regime transition temperature, morphology and phase separation were studied using polarized light microscope (PLM) with isothermal method or nonisothermal method. The morphology of specimens after chemical etching were investigated using atomic force microscope (AFM) and scanning electron microscope (SEM). The distribution of butylene succinate (BS) and TS units in PBTSu 80/20 was found to be random from the evidence of a single Tg and a randomness value close to 1.0 for a random copolymer. With the increasing of minor amounts of comonomers, the sequence length of butylene succinate decreases, and the crystallization rate and the degree of crystallinity drop. DSC heating curves of isothermal crystallized PBTSu 80/20 and PBCHDMSu 90/10 showed triple melting peaks. Multiple melting behaviors indicate that the upper melting peaks are associated with the primary and the recrystallized crystals, or the crystals with different lamellar thickness. As the Tc increases, the contribution of recrystallization slowly decreases and finally disappears. Hoffman-Weeks linear plots gave an equilibrium melting temperature of 113.5