Chip and scrub seal treatments are one of the most common pavement preservation practices, however, no performance specifications exist in Mississippi. Review of literature has shown the treatment of cores being successful in reducing the viscosity of aged asphalt pavements. The purpose of this thesis is to provide a basis for performance based specifications for surface treatments in Mississippi. This thesis provides information pertaining to viscosity, moisture loss, and frosted marble analysis of emulsions and the effects of rejuvenation after application of emulsions to aged asphalt pavements which are vital to the performance of the surface treatment. The objectives to this thesis are to determine and evaluate the effects of rejuvenation, frosted marble test, and moisture loss of emulsion applied to aged asphalt pavements. Results from these analysis’ are favorable for developing or providing a basis for performance based specifications for surface treatments applied in Mississippi.

The major objective of the research was to improve lychee postharvest management, through a greater understanding of mechanical injury and moisture loss. Mechanical injury is a known cause of postharvest loss in lychee, but previously published information has been limited to broad observations. In this study, the symptoms of mechanical damage in lychee were defined, including quantitative measurement of colour changes. Impact injury caused protuberance tip darkening, cracking of the pericarp and significant changes in skin colour. Compression also typically caused tip darkening, and severe loads were capable of puncture, shape distortion and skin cracking. Abrasion and vibration injuries were characterised by strong yellowing of pericarp colour, possibly due to the leakage of cell contents onto the fruit surface. Vibration also caused significant darkening and loss of colour saturation. Vibration has not previously been mentioned as an issue in lychee postharvest management, but appeared to be as important a problem as desiccation browning at the wholesale level, both in incidence and severity. Mechanically damaged fruit consistently showed increased ethylene and carbon dioxide synthesis, and moisture loss was increased by up to 30%. Some significant changes in skin biochemistry and cuticle properties were also detected. The study of damaged tissue by SEM revealed distinctive patterns of surface tissue disruption. Open pericarp cracking was a particularly detrimental injury, causing significantly increased electrolyte leakage and rapid pathogen development. The effects of load characteristics, such as magnitude, method of application, site, repetition and cushioning, on the extent of damage were defined. Fruit characteristics such as cultivar, gross morphology, temperature, hydration and surface wetness were shown to significantly affect damage levels. Small seed size was correlated with increased cracking susceptibility. Fruit surface wetness exacerbated vibration or abrasion damage. Turgid fruit were less susceptible to vibration and abrasion damage, but showed increased susceptibility to impact cracking. Previously neglected aspects of desiccation browning research were studied, including cultivar and maturity effects, sites of moisture loss and the role of air currents. Cultivar effects on moisture loss were obscured by pre-harvest factors, but consistent cultivar differences were detected in desiccation browning, possibly related to skin thickness. In contrast, maturity levels over a marketable range had little effect on weight loss or browning. Moisture was lost fairly evenly over the fruit surface, but poor postharvest handling appeared to massively increase loss from the protuberance tips. Moisture loss was shown to substantially increase ethylene synthesis. The crucial role of air currents in exacerbating lychee moisture loss was emphasised, and the relationship between air speed and weight loss was defined. The research contributed to a greater understanding of the processes of mechanical damage and moisture loss in lychee, leading to improved protocols for the postharvest management of the fruit. Improved management of mechanical damage and moisture loss will ultimately improve fruit quality and reduce postharvest losses, hence increasing returns to industry.

The major objective of the research was to improve lychee postharvest management, through a greater understanding of mechanical injury and moisture loss. Mechanical injury is a known cause of postharvest loss in lychee, but previously published information has been limited to broad observations. In this study, the symptoms of mechanical damage in lychee were defined, including quantitative measurement of colour changes. Impact injury caused protuberance tip darkening, cracking of the pericarp and significant changes in skin colour. Compression also typically caused tip darkening, and severe loads were capable of puncture, shape distortion and skin cracking. Abrasion and vibration injuries were characterised by strong yellowing of pericarp colour, possibly due to the leakage of cell contents onto the fruit surface. Vibration also caused significant darkening and loss of colour saturation. Vibration has not previously been mentioned as an issue in lychee postharvest management, but appeared to be as important a problem as desiccation browning at the wholesale level, both in incidence and severity. Mechanically damaged fruit consistently showed increased ethylene and carbon dioxide synthesis, and moisture loss was increased by up to 30%. Some significant changes in skin biochemistry and cuticle properties were also detected. The study of damaged tissue by SEM revealed distinctive patterns of surface tissue disruption. Open pericarp cracking was a particularly detrimental injury, causing significantly increased electrolyte leakage and rapid pathogen development. The effects of load characteristics, such as magnitude, method of application, site, repetition and cushioning, on the extent of damage were defined. Fruit characteristics such as cultivar, gross morphology, temperature, hydration and surface wetness were shown to significantly affect damage levels. Small seed size was correlated with increased cracking susceptibility. Fruit surface wetness exacerbated vibration or abrasion damage. Turgid fruit were less susceptible to vibration and abrasion damage, but showed increased susceptibility to impact cracking. Previously neglected aspects of desiccation browning research were studied, including cultivar and maturity effects, sites of moisture loss and the role of air currents. Cultivar effects on moisture loss were obscured by pre-harvest factors, but consistent cultivar differences were detected in desiccation browning, possibly related to skin thickness. In contrast, maturity levels over a marketable range had little effect on weight loss or browning. Moisture was lost fairly evenly over the fruit surface, but poor postharvest handling appeared to massively increase loss from the protuberance tips. Moisture loss was shown to substantially increase ethylene synthesis. The crucial role of air currents in exacerbating lychee moisture loss was emphasised, and the relationship between air speed and weight loss was defined. The research contributed to a greater understanding of the processes of mechanical damage and moisture loss in lychee, leading to improved protocols for the postharvest management of the fruit. Improved management of mechanical damage and moisture loss will ultimately improve fruit quality and reduce postharvest losses, hence increasing returns to industry.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The export of Japanese plums from South Africa is challenging. Exporting late season plums require fruit to last as long as 8 weeks in cold-storage. Prolonged storage periods can cause some cultivars to develop a shrivelled appearance due to moisture loss. Moisture loss from perishable commodities manifests mainly as shrivelling due to a loss in the turgidity of the surface cells of the fruit, or weight loss. ‘African DelightTM’ (highly susceptible to shrivel), ‘Laetitia’ (shrivel susceptible), ‘Sapphire’ (shrivel susceptible) and ‘Songold’ (not shrivel susceptible) plums were investigated by means of fluorescent microscopy for cracks and openings in the fruit peel. Only ‘African DelightTM’ had open hairline cracks in its peel, and fruit with wider cracks were associated with higher water vapour permeabilities. Open lenticels were found in the peels of ‘African DelightTM’, ‘Laetitia’ and ‘Sapphire’ plums. For ‘Songold’ no peel cracking or open lenticels were observed. The fact that the cuticle of this cultivar is mostly intact may be the reason why it is not susceptible to postharvest shrivel manifestation. The water vapour permeance of the fruit peel determines how easily fruit lose moisture. In this study it was determined to what extent fruit, trees, orchards, harvest date and cultivar contribute to the total variation in plum peel water vapour permeability. The permeabilities of ‘African DelightTM’, ‘Laetitia’, and ‘Songold’ were determined weekly from 4 weeks before harvest until post optimum maturity. Fruit to fruit variation made the largest contribution towards the total variation (> 45%), followed by harvest date (> 20%) and orchard (> 15%) effects. The permeability across all cultivars increased two-fold as fruit became over mature. The contribution of cultivar differences to fruit peel permeability varied greatly between seasons (42% in 2013/2014 and 5% in 2014/2015). Differences between cultivars may include cuticle thickness and composition, micro cracks in the peel and/or open lenticels. Current handling protocols suggest that fruit should be cooled as soon as possible after harvest, but this is not always possible. ‘African DelightTM’ plums were exposed to various handling scenarios in order to determine the handling protocol with the least risk of moisture loss. The control consisted of packaging and cooling the fruit within 6 h of harvest. Fruit quality was comparable or even better than the control when the fruit were pre-cooled to 0 °C and 15 °C for up to 72 h. High vapour pressure deficits caused fruit to lose more moisture, especially when fruit were exposed to ambient temperatures for 48 h and 72 h. It is recommended that handling protocols for plums should be followed stringently in order to reduce mass loss and shrivel manifestation. Since other studies found that silicate (Si) has positive effects on fruit quality, we applied potassium silicate preharvest to ‘African DelightTM’ trees. However, we did not find significant differences between treatments regarding crack width or crack incidence in the fruit peel, shrivel, decay, internal browning, gel breakdown or aerated tissue levels. Currently preharvest potassium silicate applications are not recommended to improve plum quality. / AFRIKAANSE OPSOMMING: Die uitvoer van die Japanese pruime uit Suid-Afrika is 'n uitdaging, omrede daar verwag word dat laatseisoen kultivars tot 8 weke in koelopberging moet bly. Lang opbergingsperiodes veroorsaak dat sommige kultivars 'n verrimpelde voorkoms ontwikkel a.g.v. vogverlies. Vogverlies uit vars produkte manifesteer hoofsaaklik as verrimpeling a.g.v. 'n verlies in die turgiditeit van die selle in en onder die vrugskil, en as massaverlies. ‘African DelightTM’ (hoogs vatbaar vir verrimpeling), ‘Laetitia’ (vatbaar vir verrimpeling), ‘Sapphire’ (vatbaar vir verrimpeling) en ‘Songold’ (nie vatbaar vir verrimpeling) pruime is ondersoek deur middel van fluoressensie mikroskopie vir krake en openinge in die vrugskil. Slegs ‘African DelightTM’ het oop haarlyn krake in sy skil gehad en vrugte met wyer krake het ʼn hoër waterdamp deurlaatbaarheid gehad. Oop lentiselle is gevind in die skille van ‘African DelightTM’, ‘Laetitia’ en ‘Sapphire’ pruime. ‘Songold’ het geen krake of oop lentiselle getoon nie. Die feit dat ‘Songold’ se kutikula meestal ongeskonde was, mag die rede wees waarom hierdie kultivar nie vatbaar vir verrimpeling is nie. Die waterdamp deurlaatbaarheid van 'n vrugskil bepaal hoe maklik vrugte vog verloor. In hierdie studie is bepaal tot watter mate vrugte, bome, boorde, oesdatum en kultivar bydra tot die totale variasie in die pruimskil se waterdamp deurlaatbaarheid. Die deurlaatbaarheid van ‘African DelightTM’, ‘Laetitia’, en ‘Songold’ is weekliks bepaal vanaf 4 weke voor die verwagte oesdatum tot die vrugte oorryp was. Vrug tot vrug variasie het die grootste bydrae tot die totale variasie gemaak (> 45%), gevolg deur oesdatum (> 20%) en boord (> 15%). Die skildeurlaatbaarheid van al die kultivars het verdubbel in die tyd van net voor oes tot die vrugte oorryp was. Die kultivar se bydrae tot die deurlaatbaarheid van die vrugskil het baie gewissel tussen seisoene (42% in 2013/2014 en 5% in 2014/2015). Verskille in skil-deurlaatbaarheid tussen kultivars kan kutikula-dikte en -samestelling, mikro-krake in die skil en/of oop lentiselle insluit. Huidige hanteringsprotokolle stel voor dat vrugte so spoedig moontlik afgekoel word na oes, maar dit is nie altyd moontlik nie. In hierdie studie is 'African DelightTM' pruime is blootgestel aan verskeie hantering scenario's om die hanteringsprotokol met die laagste risiko vir vogverlies te bepaal. Die kontrole vrugte is gepak en onder geforseerde verkoeling geplaas binne 6 ure na oes. Vrugkwaliteit was vergelykbaar of selfs beter in vergelyking met die kontrole wanneer die vrugte voorverkoel is tot 0 °C en 15 °C vir tot 72 uur. Hoë dampdrukverskille het veroorsaak dat vrugte meer vog verloor, veral wanneer vrugte aan kamertemperatuur blootgestel was vir 48 h en 72 h na oes. Dit word aanbeveel dat hanteringsprotokolle vir pruime streng gevolg moet word om massaverlies en verrimpeling te beperk. Aangesien ander studies gevind het dat silikaat (Si) ‘n positiewe uitwerking op vrugkwaliteit het, het ons kaliumsilikaat vooroes aan ‘African DelightTM’ bome toegedien. Daar was egter geen beduidende verskille tussen behandelings met betrekking tot kraakbreedte of kraakvoorkoms in die vrugskil of t.o.v. gehalte eienskappe soos die voorkoms van verrimpeling, bederf, interne verbruining, gelverval of deurlugte weefsel nie. Tans word voor-oes kaliumsilikaat spuite nie aanbeveel om pruimkwaliteit te verbeter nie.

Made available in DSpace on 2017-07-10T17:37:17Z (GMT). No. of bitstreams: 1 Elcio_Friske.pdf: 2134254 bytes, checksum: a68baa9abb11f51692fe7500a517561f (MD5) Previous issue date: 2016-02-29 / Fundação Araucária / The aim of this work was to evaluate the genetic diversity and map genomic regions associated with grains maturation in common corn lineages. The phenotypic attributes of 81 elite inbred lines of corn were assessed in field experiment implanted in square lattice design with three repetitions. The variance and multivariate analysis were carried out considering complete randomized blocks due to its equivalence with the estimation for the lattice efficiency. For the mapping by linkage disequilibrium, 72 elite inbred lines have been genotyped for SNP markers at platform 650K (Affymetrix®) and associated with the genotypic values of the traits related to maturation: number of days for the male flowering (DFM) and female (DFF), and the grain moisture loss, determined by the area below the moisture curve (AACUM). The results of the variance analysis pointed out the existence of genetic diversity in the germplasm for all the assessed traits, detecting a wide variability for DFM, DFF and AACUM. Weak genetic correlations between yield and maturation components indicated the possibility of selection for earliness without compromising the grain yield. The genetic diversity quantified by the distances of Mahalanobis enabled the suggestion of hybrid combinations of higher heterotic effect for earliness and grain yield. There were similarities in the Tocher and UPGMA grouping, which were efficient to classify the genetic variability. By the mixed linear model (MLM) it was possible to detect associations among days for male and female flourishing with SNP markers in all chromosomes, with predominance of chromosomes 1 and 3 and for the loss of moisture in the chromosomes 5 and 6. With of multiple regression analysis of stepwise for DFM, DFF and AACUM, the complete models explained 79%, 93% and 56% of the variation for the genotypic values, respectively, being found predominantly significant markers in the chromosomes 1 and 3. The detection of similar and also different genomic regions for these traits, which are highly correlated, makes possible to raise the hypothesis of the importance of the genetic linkage and pleiotropy to explain the maturation of grains in corn inbred lines. The results obtained are promising and the genomic regions associated with DFM, DFF and AACUM, will be evaluated in validation experiments, which will be useful in selection programs of genotypes with the maturity sought by the breeder / O trabalho teve como objetivos avaliar a diversidade genética e mapear regiões genômicas associadas com maturação de grãos em linhagens de milho comum. Os atributos fenotípicos de 81 linhagens elites de milho foram avaliados em experimento de campo implantado em delineamento de látice quadrado com três repetições. Procedeu-se a análise de variância e multivariada considerando blocos completos casualizados devido a sua equivalência com a estimação para eficiência do látice. Para o mapeamento por desequilíbrio de ligação, 72 linhagens elites foram genotipadas para marcadores SNP na plataforma 650K (Affymetrix®) e associados aos valores genotípicos dos caracteres relacionados à maturação: número de dias para o florescimento masculino (DFM) e feminino (DFF), e perda de umidade dos grãos, determinada pela área abaixo da curva de umidade (AACUM). Os resultados da análise de variância indicaram a existência de diversidade genética no germoplasma para todos os caracteres avaliados, detectando-se ampla variabilidade para DFM, DFF e AACUM. Correlações genéticas fracas entre os componentes de rendimento e de maturação indicaram a possibilidade de seleção para precocidade sem comprometer a produtividade. A diversidade genética quantificada pelas distâncias de Mahalanobis permitiu sugerir combinações hibridas de maior efeito heterótico para precocidade e produtividade. Houve semelhanças no agrupamento de Tocher e UPGMA, que foram eficientes para classificar a variabilidade genética. Pelo modelo linear misto (MLM) foi possível detectar associações entre dias para o florescimento masculino e feminino com marcadores SNP em todos os cromossomos, com predominância nos cromossomos 1 e 3, e para perda de umidade nos cromossomos 5 e 6. Com a análise de regressão múltipla de stepwise para DFM, DFF e AACUM, os modelos completos explicaram 79%, 93% e 56% da variação para os valores genotípicos, respectivamente, encontrando-se predominantemente marcadores significativos nos cromossomos 1 e 3. A detecção de regiões genômicas semelhantes e também distintas para esses caracteres, que são altamente correlacionados, torna possível levantar a hipótese da importância de ligação gênica e de pleiotropia para explicar a maturação de grãos em linhagens de milho. Os resultados obtidos são promissores e as regiões genômicas associadas com DFM, DFF e AACUM, serão avaliadas em experimentos de validação, que poderão ser úteis em programa para seleção de genótipos com a maturidade buscada pelo melhorista

Chip seals are a commonly used surface treatment used to decrease the deterioration rate of pavement surfaces. Chip seals typically consist of an application of emulsion and cover aggregate. Failure can be driven by improper strength development and inadequate bonding over time. Additionally, chip seal service life varies and long term performance prediction models are not well established. This study has two primary goals. The first goal is to investigate aggregate retention characteristics of chip seal specimens, while investigating material compatibility by means of the Sweep-M test. The second goal is to begin developing a long term performance (LTP) test to represent cores obtained from full-scale chip seal projects. Conditioning and testing protocols for LTP specimens are evaluated for representative chip seal behavior over long periods. Results confirm material interaction and favor the incorporation of sweep testing for optimum performance. Future testing is recommended for in-depth, LTP test protocol evaluation.

Tyrimų tikslas – laboratorinėmis sąlygomis eksperimentiškai nustatyti džiovinimo vainikinio išlydžio elektriniame lauke efektyvumą ir palyginti jį su džiovinimu elektromechaniniu ventiliatoriumi. Darbe aptariami kviečių ir gražgarstės lapų džiovinimo vainikinio išlydžio lauku eksperimentinio tyrimo rezultatai naudojant elektrodų sistemą „lygiagrečių laidų tinklelis virš įžemintos plokštumos“. Darbe apžvelgtos technologijos pagrįstos vainikinio išlydžio lauko naudojimu Tyrimai atlikti Kauno technologijos universitete elektromagnetinių laukų įtaisų mokslinėje laboratorijoje, su įtaisu kurį sudaro aukštos įtampos šaltinis ir elektrodų sistema „lygiagrečių laidų tinklelis virš įžemintos plokštumos“. Atliktas joninio ir elektromechaninio ventiliatoriaus oro srautų palyginimas. / The aim of the research is to establish experimentally the effectiveness of drying affected by the corona field in comparison with the effectiveness of drying affected by the external airflow driven by electromechanical ventilator. Review of various techniques applying of corona field is given. Results of wheat drying by using the corona field of electrode system „ a set of parallel wires under the grounded plate“ are presented and discussed. Experimental study of drying is performed in Research laboratory of electromagnetic field devices of Kaunas university of technology. Test drying device consists of the high voltage source and the electrode system „a set of parallel wires under the grounded plate“. Comparison of corona field airflow and electromechanical ventilator airflow is given.