Background and objectives: While alkaline nixtamalization has historically been used for corn, this process may have application in other cereals. Drawbacks to wider use include the lengthy steep time, as well as the volume of alkaline wastewater produced. This study evaluated a novel, waste-effluent-free nixtamalization process for oat (Avena sativa) masa, and compared properties of oat masa and tortillas prepared with 1, 1.5 and 2% lime, with and without steeping. Findings: A minimal water-addition, 45-min, simmering process, without steeping, was effluent-free, and produced oat tortillas comparable to those produced using a traditional overnight steep. The pH increased significantly with increasing lime content (r=0.982). Consumer overall-liking scores did not significantly differ across treatments, though appearance scores were significantly higher for 2% lime samples (p<0.05), which were significantly darker and more yellow, based on L* and b* values. Masa adhesiveness means ranged from 1.49-1.52 N, with no significant differences between the no-steep treatments. Higher lime addition (1.5-2%) in the no-steep process significantly improved tortilla flexibility, based on extensibility and rollability scores, though tortilla rupture force did not vary significantly across treatments. Tortilla rollability scores at 3-days were lowest (x=1.1 + 0.31, indicating less cracking) for the 1.5-2% lime no-steep treatments, which were significantly better than the steeped treatment (x=3.7 + 0.48). Consumers rated the steeped sample as significantly less flexible. B-vitamins were negatively impacted by increasing lime, while calcium increased significantly with lime addition. Conclusions: The no-steep, effluent-free nixtamalization process produced oat tortillas with good masa and tortilla texture, which were not significantly different in consumer liking to tortillas produced via a traditional process. Significance and novelty: This research suggests nixtamalization can be applied to other grains in a shorter, environmentally-friendly process, with broader commercial applicability.

Dry Pea or field pea (Pisum sativum L.) is an important cool season legume crop grown in the United States. Field peas are vulnerable to many diseases of which, soil borne diseases including wilt and root rot are of major economic importance and can cause significant reduction in yield. There is a dearth of satisfactory methods for control of root rot and no varieties with complete resistance to Fusarium root rot are currently available. Root rot disease was found to be prevalent in all the major pea growing counties of North Dakota surveyed in 2004, 2005, 2010 and 2011. Fusarium species were the most frequently isolated fungal species from the infected pea roots of which, F. oxysporum and F. avenaceum were the most common. 21 Field pea varieties were screened for resistance against F. avenaceum and F. solani f. sp. pisi, the Fusarium species traditionally associated with root rots of field pea in growth chamber experiments and field trials. Low levels of resistance were detected in a few cultivars but no variety was found to be completely resistant to any of the pathogens tested. Efficiency of precipitated calcium carbonate (PCC) in controlling Fusarium species most commonly associated with root rots was evaluated under in vitro and field conditions. Significant reduction in spore production, spore germination, and dry mycelial weight of Fusarium spp. were detected on PCC amended media in laboratory studies. In greenhouse and field experiments significant reduction in root rot disease severity was observed with PCC application compared to control. Fungal gene expression in artificially infected field pea roots and F. graminearum grown in culture was assessed using the Illumina mRNA-Seq technology. A total of 613 F. graminearum genes were found to be differentially expressed in planta on pea. Functional classes associated with amino acid metabolism, nitrogen metabolism, extracellular polysaccharide degradation, detoxification by degradation and defense related proteins were found to be significantly enriched in the up-regulated gene set as determined using FunCatDB. Expression of four up-regulated genes was confirmed by RT-PCR to validate the inferences from the sequencing results.

Natural pozzolanic materials played an important role in Ancient architecture. In the last decades and nowadays it is artifical pozzolan which especially finds its use as an additive to mortar and concrete to improve some, especially the mechanical properties. This master thesis deals with study of pozzolan type of fine brick powder which is a by-product of the production of calibrated bricks. Along with studying pozzolanic activity of brick powder, lime mortar with different proportions of brick powder as an additive or replacement of lime dust are investigated. What is observed is its impact on the consistency of these mortar, water absorption, strength in time or fracture-mechanical parameters of mortar. The results may indicate the possible potential use of this source of pozzolanic admixture in lime mortar and plaster which are nowadays mainly used for the restoration of facades of historic buildings.

Ground improvement by deep mixing (DM) is a generic term used for a number of methods in which a binding agent, often lime and/or cement, is mechanically mixed with the soil to increase its engineering properties. The inherent variability with respect to the engineering properties of the improved soil is high due to the variations in geology and the complex mixing process. High variability introduces uncertainty in estimating improved soil properties and the performance of the structure. Current design methodology deals with soil properties deterministically and the uncertainties involved are incorporated in a single value represented by a total factor of safety (FS). The chosen FS is highly dependent on the engineer’s judgment and past experience, in which both of these factors vary between different geotechnical designers. Therefore, current design methodology used in practice for DM does not deal with uncertainties in a rational way. In order to design a geotechnical system with the desired level of confidence, the uncertainties involved must be integrated in the DM design. This can be achieved by using reliability-based design (RBD) methods. The research work in this thesis is presented as a collection of three papers. In the first paper, a comprehensive statistical analysis of cone penetration test (CPT) data is described. The objective was to make a contribution to empirical knowledge by evaluating the strength variability of lime-cement columns within the group of tested columns. In the second paper, the effect of the spatial variability and statistical uncertainty with regard to the embankment’s reliability was investigated within the framework of RBD. The study in the third paper investigated the strength variability in lime-cement columns based on two test methods, namely CPT and column penetration test (KPS). In this study, the effect of different test methods on the evaluation of the design value was addressed. The main conclusions from this study can be summarized as follows. First, the probability distribution function (PDF) for the undrained shear strength of lime-cement columns can be modeled in RBD as normal or log-normal distributions. However, the use of log-normal distribution is recommended for RBD analyses. Second, the evaluated scales of fluctuation indicate ranges of 2 to 4 m and 0.2 to 0.8 m in the horizontal and the vertical directions respectively. This means that in order to fulfill the requirements of independent/uncorrelated samples for assessment of the design value, the spacing between samples must exceed the horizontal scale of fluctuation. It is therefore proposed that the spacing between individual samples should be at least 4 meters. Third, the design values evaluated using CPT and KPS were approximately the same. However, the inherent variability evaluated differs due to the larger volume tested with the KPS probe than with the CPT probe. However, this difference was not significant between the two tests. Fourthly, due to the limitation in the deterministic design in terms of dealing with uncertainties, it is recommended that RBD design should be used in parallel with the deterministic design of lime-cement column. / <p>QC 20120110</p>

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Mining in Peru has existed for several decades, and for several years, there has been no proper environmental management of the impact of this activity on the environment and society in general, whether it be gas emissions, the presence of acidic water, or the generation of mining tailings. One of the most prominent examples involve mine tailings; these are by-products of mining processing plants and are stored in a dam known as a tailings dam. Like any extraction activity, mining generates large amounts of waste material that could become potential risks to the environment and society. Using hydraulic fills, the mine tailings contained in tailings dams could be reused. These fills seek to decrease the volume of stored tailings to prevent any future dam collapses, as observed in Brazil with the Vale mining company, where its tailings dam collapsed and caused more than 200 deaths.

Clay soils can be stabilized by the chemical reaction between the clay particles and lime to produce calcium aluminate and calcium silicate minerals. This cementation effect on clay particles result in increasing the strength of lime-treated clay soils. The mechanical strengths (compressive, tensile and shear strengths) of clay soils are improved from soft to stiff behavior by treating with lime and evolve along the curing time.An extensive experimental investigation has been carried out using laboratory reconstituted (compacted) expansive soils, covering a range of plasticity indices. Four selected soils with different fundamental physical and mechanical behaviors have been used to stabilize with lime. In addition to basic geomechanical characterization tests (modified proctor compaction, uniaxial compression strength, indirect tensile strength, oedometric compression, direct shear tests), a special focus was put on triaxial compression and extension tests upon drained and undrained conditions. Also, the development of swelling pressure upon wetting was also carefully investigated.The shear behavior of compacted clay soils is experimentally investigated by using both direct shear test and triaxial shear tests. These tests were conducted on saturated specimens for four selected soils. It is observed that the shear strength of both tests is evolving with addition of lime and with the plasticity index. In addition to the strength parameters, triaxial shear test was also used to determine the Young modulus of treated soils. It was noticed that the lime treatment increases the elastic modulus of selected clay soils.The triaxial compression system was modified to a triaxial extension system in order to evaluate the triaxial tensile strength of one of the tested soils (N1, from Quenast, Belgium). The pure tensile strength of soils can be determined from triaxial extension test at low confining pressures while high confining pressures induces shear failure.The failure criteria of lime-treated soils were studied in different stress planes to evaluate the shear and tensile strength obtained from triaxial extension test and triaxial compression test. A combined rupture criterion of original and modified Griffith criteria was applied. The results obtained from experimental testing have shown that at low confining pressures, the failure stress of extension test followed the Original Griffith Criterion started from pure tension, and at the higher confining pressures the failure stress followed the Modified Griffith (equivalent to Mohr-Coulomb, in this case).In application of this combined equation, the result of four selected soils obtained from triaxial tension test, direct shear test and triaxial compression test was plotted in the (sigma,to) in order to verify this equation. These experimental results match with the combined equation.This analysis revealed the strong interest of extension triaxial tests, with respect to more conventional indirect tension tests (also called splitting tests). Extension triaxial tests allow to control the drainage conditions and performed a full effective stress analysis of the stress-strain responses, including pre-failure behavior and ultimate strength criterion. Also, it provides a smooth transition between shear strength and tensile strength criterion, depending on the confining pressure of the test.At the end of this work, experimental results are analyzed and correlated with several parameters. Shear strength, compression index and swelling pressure were found to depend primarily on plasticity index for both treated and untreated materials. Many approaches in literature have also expressed these mechanical properties of soils in function of plasticity index. However, there are a few equations matching closely to testing results. For the development of swelling pressure upon wetting, a modified equation was proposed for experimental data for non-treated soils and lime-treated soils. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

Byggbranschen står för ca 20 % av Sveriges totala utsläpp av koldioxidekvivalenter och Sverige har som mål att inte ha några nettoutsläpp av växthusgaser år 2045. Det behöver därför göras något för att minska utsläppen. Olika material genererar olika mycket utsläpp av växthusgaser under sin livscykel och ett sätt att minska utsläppen är därför att välja material med låga utsläpp. Syftet med studien är att med hjälp av livscykelmetodik jämföra bidrag till klimatpåverkan från en bullerskärm med träullsskivor och en med lime hempcrete-panel. Förhoppningen är att denna studie kan få beställare av bullerskärmar att välja en skärm som bidrar till ett mindre utsläpp av växthusgaser. De metoder som valts för att kunna besvara studiens frågeställningar är litteratursökning, intervju, livscykelmetodik och ett beräkningsverktyg, förenklade klimatåtgärdsverktyget. Studien pekar på att den bästa bullerskärmen för miljön är den av lime hempcrete, dock har även bullerskärmen av träullit liten klimatpåverkan då även den är gjord av biobaserade material som binder koldioxid. För att minimera utsläppen för båda bullerskärmarna ytterligare finns det olika metoder, byta drivmedel för arbetsmaskinerna, minimera transportsträckor och att använda återvunnet stål & metall. Det finns inga direkt jämförbara eller opartiskt granskade värden för koldioxidbindning vilket kan anses påverkar validiteten för studien. Då emissionsvärdena för koldioxidbindning har hämtats genom litteraturstudier har variationen bidragit till att två extremvärden har valts för beräkningarna. Detta kan tyckas ge en mer representativ bild av materialen då hela spannet tydliggörs. En standardiserad metod för om/hur beräkning med koldioxidbindning ska göras hade skapat en transparens vid beräkning av livscykelanalyser för biobaserade material. / The construction industry accounts for about 20% of Sweden's total emissions of carbon dioxide equivalents and because Sweden aims to have no net greenhouse gas emissions by 2045, something must be done to minimize emissions. Materials generate different emissions during their life cycle and one way of reducing emissions could be to choose materials with low emissions. The purpose of the study is to compare contributions to the climate impact between a noise screen with wood wool boards and one with lime hempcrete panel, using life cycle methodology. The methods chosen for the study are literature search, document analysis, interview, life cycle methodology and a calculation tool, förenklade klimatåtgärdsverktyget.The study indicates that the best noise screen for the environment is that of lime hempcrete, however the noise screen of wood wool also have little climate impact, since it is also made of bio-based materials that bind carbon dioxide. To minimize emissions for both noise screens further, there are different methods, changing fuel for the working machines, minimizing transport distances and using recycled steel & metal.There are no directly comparable or partially examined values for carbon dioxide binding which can be considered to affect the validity of the study. As the emission values for carbon dioxide binding have been obtained through literature studies, the variation has contributed to the selection of two extreme values for the calculations. This may seem to give a more representative view of the materials as the entire span is clarified. A standardized method for how calculation with carbon sequestration should be done would create a transparency in the calculation of life cycles for bio-based materials.

Chlorosis of plants from a lack of available iron is one of the most common plant nutrient problems of the calcareous soils of the west. The disease is characterized by a yellowing of the plant leaves and is accompanied, in severe cases, by a partial root death and premature defoliation (3). In addition to reducing growth, the disease greatly reduces the quality and yield of plants. Many types of plants are affected by iron chlorosis. In Hawaii and Porto Rico rice, sugar cane and pineapple are susceptible, while in California and Arizona, citrus trees are seriously affected. In Utah apples, peaches, plums, prunes, apricots, pears, grapes, raspberries and many ornamental plants are affected (27). The problem of iron chlorosis, therefore, is of great importance to agriculture in the west. Chlorosis has been studied for more than one hundred and fifty years, but until recently, little progress has been made toward finding the solution to the problem. Although these past studies have not solved the problem of iron chlorosis, they have shown many factors to be closely related to the occurrence of the disease. These factors include an unbalanced ratio of available manganese to iron in the growth medium (9, 23, 29); chlorotic leaves are high in potassium, nitrogen in the form of ammonia (21), and in ferric iron and are low in total calcium and ferrous iron in comparison with green leaves (12, 13, 14, 17, 25, 26). The climatic factors of light, soil temperature and soil moisture also appear to be of fundamental importance in chlorosis. It is a common observation that fruit trees are more chlorotic during the early spring when the temperature of the soil is low and the moisture level high. Many investigators have noted that chlorosis tends to be most severe in the poorly drained portions of fruit orchards when water tends to accumulate. However, the work on the affect of climatic conditions on chlorosis has been limited largely to observations. The purpose of this investigation was to study, under controlled conditions, the effect of light, soil temperature and soil moisture on a lime-induced chlorosis.

Chlorosis, the yellowing of plant leaves, results from reduced synthesis of chlorophyll. It is caused by a deficiency or an unbalance of essential nutrient elements. The amount and pattern of yellowing varies with the cause and severity of the disturbance. Chlorosis results in reduced vigor of the affected plants and a corresponding loss in quantity and quality of the product grown. In severe cases chlorosis may lead to the eventual death of the plant. Lime-induced chlorosis refers to a chlorosis occurring on high lime soils. It affects principally horticultural plants. The disease is found in about 23 percent of Utah orchards. Lime-induced chlorosis is characteristically accompanied by high potasseium in the affected leaves. The hypothesis had been offered that this high potassium is a cause of lime-induced chlorosis. The object of this study is to investigate the validity of this hypothesis.

Construction of pavements requires the subgrades - which are the foundation of the structure, to be capable of supporting traffic loads that would be applied onto them. In the case that the subgrades are unable to support the structure, failure would occur. The subgrade being in-situ soil can be of poor quality if not properly constructed or improved if necessary. In Canada, the eastern region precisely Ontario and Quebec, is dominated by sensitive marine clays which when disturbed lose their strength drastically making them a geotechnical hazard. The soil's high sensitivity causes this behavior it poses. Therefore, to construct pavements in this type of soil, improvement techniques are required. One such is lime stabilization which improves the engineering properties of the soil. Research on the stabilization of sensitive marine clay in Canada has been conducted to a certain extent showing the effectiveness of the process in improving the soil's poor engineering properties. However, during the process of stabilization, the thermal (T), hydraulic (H), mechanical (M) and chemical (C) processes and interactions that occur influence the behavior of the stabilized clay. Environmental stresses such as moisture and temperature are also known to affect the coupled processes that occur. However, these coupled processes and their impact on the stabilized clay are not well known and understood. The goal of the research was to therefore, conduct various column experiments and monitoring to determine the evolution of the coupled THMC processes under normal curing and when daily thermal cycles were applied to the treated and untreated clay. Various columns were prepared in the laboratory to accommodate the compacted treated and untreated sensitive marine clay for monitoring over 28 days. In addition, columns from which samples for extensive geotechnical testing were collected, were prepared. The soils' strength and hydraulic conductivity were determined through testing while the suction, electrical conductivity and temperature evolution were determined by use of sensors placed within the columns. The developed mechanical properties of the soil were significantly improved by use of lime. This development of mechanical properties was further enhanced when the daily thermal cycles were applied to the soil due to increased curing temperature stimulated. In addition, to temperature and chemical reactions, it was observed that the hydraulic properties also contributed to the developed soil strength. The strongly coupled THMC processes were thus, observed during the treatment of the clay with lime. The results obtained will therefore, contribute to a better understanding of the coupled THMC processes that occur when sensitive marine clay is treated with lime. It will further contribute to cost effectively designing pavements in regions with sensitive marine clays or similar.