Dissertations / Theses on the topic 'Partial replacement of cement'

The work in this thesis examines the suitability of utilising ground waste brick as a cement replacement material. The brick types investigated were obtained from the UK,Denmark, Lithuania and Poland. Cement was partially replaced by various quantities and types of ground brick in mortar and concrete. Compressive strength, pore size distribution and sorptivity of mortar generally all benefit from the presence of ground brick and the greatest effect can be seen after water curing for one year. Compressive strength of concrete is also shown to increase as the fineness of ground brick increases although the optimum particle size for ground brick in concrete is still to be determined. The ground bricks investigated have a significant effect on the performance of ground brick mortar when exposed to sodium sulphate solution and synthetic seawater. It is seen that depending on the chemical and phase composition, the effect of ground brick can increase substantially the rate of deterioration of mortar or can reduce significantly the expansion observed. No definite mechanism was identified as being responsible for the observed deterioration of mortar exposed to sodium sulphate solution although it seems likely that water intake due to ettringite formation and adsorption of water by the resultant colloidal product are the primary causes of expansion. Sulphate content, glass content and oxide chemistry of brick are key factors as to its performance when used as a cement replacement material in mortar. Bricks with a high proportion of low calcium glass make very effective pozzolans. Bricks with high calcium glass or a low proportion of glass should not be used as pozzolans. Small amounts of sulphate in ground brick do not have any serious deleterious effects on ground brick mortars and can be beneficial. It is established that it is technically feasible to partially replace cement with ground brick in mortar and concrete, depending on its chemical and phase composition to produce a more durable, cost effective and (due to the lower cement content) a less environmentally damaging material than that produced without cement replacement.

Utilization of fly ash as a supplementary cementitious material adds sustainability to concrete by reducing the green house gas emission associated with cement production. Fly ash is a by-product of coal fired power stations. The properties of fly ash depend on the type of coal and its burning process. Due to the variation in composition, different fly ash affects the properties of concrete differently. Research data on the performance of concrete containing the Western Australian fly ash is scarce in literature. In this study, mechanical and durability properties of high strength concrete using Class F fly ash from Western Australia were investigated. The ACI 211.4R-08 guidelines were followed to design two series of concretes, each having one control concrete and two fly ash concretes using 30% and 40% fly ash as cement replacement. Fly ash concretes of series A were designed by adjusting the water to binder (w/b) ratio and total binder content to achieve the same strength grade of control concrete. In series B, w/b ratio and total binder content were kept constant in all the three mixtures. Samples were water cured for 7 and 28 days; and were tested at different ages. The mechanical properties were tested by compressive strength, tensile strength and flexural strength test. The investigated durability properties were drying shrinkage, volume of permeable voids, water and air permeability, carbonation and chloride ion penetrability.The 28-day compressive strength of the concrete mixtures varied from 65 to 85 MPa. The fly ash concretes showed lower drying shrinkage than control concrete when designed with adjusted w/b ratio and the total binder content. Inclusion of fly ash reduced sorptivity and water permeability significantly at 28 days. Fly ash showed no adverse affect on air permeability of concrete. Fly ash concretes showed similar carbonation and had less chloride ion penetration as compared to the similar grade control concrete. In general, incorporation of fly ash as partial replacement of cement improved the durability properties of concrete at early age when w/b ratio was adjusted to achieve similar 28-day strength of the control concrete. The durability properties improved with the increase of fly ash content from 30% to 40% of the binder and with the increase of age. Fly ash concretes of series A achieved similar service life of control concrete in carbonation and resulted in higher service life than that of the control concrete, when chloride diffusion was considered as the dominant form of attack.

Concrete is an integral material in modern infrastructural requirements worldwide. The production of Portland cement is however expensive, energy intensive, and results in globally significant greenhouse gas emissions. Natural pozzolans such as pumice can be used as a partial replacement for Portland cement in concrete, which can reduce production costs and greenhouse gas emissions, and improve concrete performance. A fluvial pumice deposit which may be suited for use as a natural pozzolan has been identified on the floodplains of the Waikato River. A sample was milled in Germany, and returned to New Zealand in two subsamples. These were tested in concrete, with tests divided into four rounds. The first two rounds established baseline concrete strengths at water/binder (w/b) ratios of 0.6 and 0.5, with pumice replacing cement at 5, 10, 15 and 30%. Round Three assessed the use of high pH mix water (pH=12.9), and Round Four assessed the use of a polycarboxylate superplasticiser, both with 10% pumice. Pumice is known to retard early concrete strength, however through optimisation of mix design, improvements in concrete strength and durability can be made. Indeed, all 28 day concrete strengths in this research were below Ultracem, however half of these achieved or exceeded Ultracem strengths at 91 days. The use of superplasticiser achieved the best 28 day concrete strengths, and dosage optimisation is expected to yield further improvements. Concrete durability was tested at w/b=0.5, with 10% and 30% pumice. After prolonged curing (231 days), composite concrete showed substantial improvements in electrical resistivity and resistance to chloride attack, most notably with 30% pumice. Concrete porosity was essentially unaffected. This pumice has shown significant promise as a partial cement replacement. Further mix optimisation is likely to yield greater improvements in concrete strength and durability, and will provide a more economically and environmentally sustainable product for the New Zealand concrete market.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 73-76).<br>Cement is a very valuable commodity as it can be used to construct structurally sound buildings and infrastructure. However, in many developing countries cement is expensive due to the unavailability of local resources to produce enough cement in-country to meet the demand for this material, and therefore it has to be imported. In rice-producing countries rice husk ash-a material naturally high in silica-can be used as a supplementary cementitious material and can substitute a portion of Portland cement in concrete without sacrificing the compressive strength. This study investigates the use of Cambodian rice husk ash in 10, 20 and 30% replacements of Portland cement by mass in mortar, without optimization of the ash by controlled burning. Five ashes collected from different sources in Cambodia were assessed for their suitability for use in rural Cambodian construction via compression strength testing of 2" (50 mm) mortar cubes. A 20% replacement of unprocessed Cambodian rice husk ash was deemed appropriate for use in small-scale, rural structural applications. Low-tech methods of grinding the ash were also investigated and were found to drastically increase the compressive strength of RHA-cement mortars in comparison to mortars made with unground RHA.<br>by Dorothy Kamilah Brown.<br>S.M.

The use of asbestos fibres in construction products has been banned in European countries for about two decades due to its effect on human health. At present, many developing countries use asbestos cement board as one of the most important construction products for roofing, cladding and partition walls. The Hatschek process is the most commonly used method to produce asbestos Fibre Cement Board (FCB). There are two major problems for the asbestos FCB manufacturers in replacing their products with non-asbestos FCB. The first one is finding materials and fibres that are available and competitive in price compared to asbestos fibres, and the second is providing inexpensive machines and equipment to produce non-asbestos FCB. In this research, an effort has been made to solve these two major problems. After the initial laboratory investigations on several natural and synthetic fibres some of the fibres with potential use in FCB were chosen for the further investigations. A slurry vacuum dewatering process was then designed and made for the laboratory use. The performance of material selections and mix designs selected from the laboratory studies were subsequently verified with factory Hatschek process in a factory site trial. Many specimens with natural and synthetic fibres incorporating silica fume and limestone powder were made and tested in the laboratory. Silica fume and limestone powder were used for enhancing flexural strength and suppression of alkalinity to reduce breakdown of the cellulose fibres. The results of mechanical, physical and II durability tests were analysed. The microstructure of the fibres and composites was also studied by SEM (Scanning Electron Microscopy). At some stages, mix design optimization was carried out to gain the highest flexural strength. The most suitable mixes were chosen for the factory site trials. A number of full-scale non-asbestos trial boards were made successfully in an asbestos FCB factory and tested in accordance with the current national and international standards. The results indicated that the trial boards fulfilled the requirements of the relevant standards. Based on the outcome of this research, a combination of acrylic fibres and waste cardboard in a mix incorporating silica fume and limestone powder in addition to Portland cement can be used to replace asbestos fibres. Although broadly compatible with the asbestos cement production process, this formulation change will necessitate some changes to the existing production lines in asbestos cement factories to produce non-asbestos FCB.

Cement replacement materials are by-products used to produce high performance concrete. Published data on the effects of combinations of mineral admixtures in concrete on the microstructural and performance-related properties under different curing regimes are comparatively little. Further the correlation of strength of concrete to its permeability and pore structure is also not clear. The main objective of this research is to study the performance of various combinations of fly ash/silica fume and slag/silica fume concretes under three different curing regimes, viz. continuous moist curing, no moist curing after demolding and air drying after 7-days of initial moist curing. Six different concrete mixes were prepared with ordinary portland cement and a blend of portland cement and combinations of fly ash+silica fume and slag+silica fume The water-to-cementitious materials ratio of all the concrete mixtures was kept constant at 0.45. The properties investigated included workability of the fresh concrete, engineering properties such as cube and modified cube compressive strength, flexural strength, dynamic modulus of elasticity, pulse velocity, shrinkage and swelling, permeability and microstructural properties such as porosity and pore size distribution. The results show that prolonged dry curing results in lower strengths, higher porosity, coarser pore structure and more permeable concretes. It was found that the loss in early age compressive strength due to incorporation of fly ash or slag can be compensated for by the addition of small amounts of silica fume. The engineering and microstructural properties and permeability of concretes containing fly ash or slag appear to be more sensitive to poor curing than the control concrete, with the sensitivity increasing with increasing amounts of fly ash or slag in the mixtures. The incorporation of high volumes of slag in the concrete mixtures refined the pore structure and produced concretes with very low porosity and threshold diameters. The results emphasize that a minimum 7-day wet curing is needed for concrete with mineral admixtures to develop the full potential, and that continued exposure to a drying environment can have adverse effects on the long-term durability of inadequately cured slag or fly ash concretes. The results also confirm that compressive strength alone is not an adequate index to judge the performance of concrete, and the knowledge of the strength, pore structure and permeability are required for this purpose. Slag/silica fume concrete mixtures showed better performance than fly ash/silica fume concrete mixtures as regards the development of engineering and microstructural properties.

Concrete has the largest production of all man-made materials. Compared with other construction materials, it possesses many advantages including low cost, general availability of raw materials, low energy requirement and utilization under different environmental conditions. Therefore, concrete will continue to be the dominant construction material in the foreseeable future. However, durability of concrete and reinfored concrete structures are still of worldwide concern, so producing a good quality concrete which impedes the ingress of harmful substances into it is of paramount importance. Cement replacement materials have been introduced into concrete mixtures for the purpose of improving the durability performance. Hence, the aim of the present investigation is to study the durability of concrete with and without cement replacement materials under various initial curing conditions. In this thesis various concrete mixes with and without cement replacement materials were considered. The cement replacement materials were, pulverised fuel ash, condensed silica fume, and ground granulated blast furnace slag. Superplasticiser was added to the majority of the mixes considered and air entraining agent to some of the mixes. Various curing regimes were employed which comprised hot dry curing to simulate concrete in the hot arid areas in the world and curing at normal temperature. Curing involved air curing, membrane curing and moist curing for fourteen days followed by air curing. A number of tests were conducted at either one particular age or at various ages. These included tests on porosity and pore structure of pastes obtained by mercury intrusion porosimetry technique, water absorption which covers the water absorption of concrete obtained by shallow immersion and the water absorbed by capillary action when the concrete surface is in contact with water, sulphate resistance of concrete which is performed by immersing the concrete specimens in sulphate solution, and monitoring the change in length at various periods of immersion, chloride penetration profiles of concrete at various ages of exposure. In addition to these tests on durability related properties, tests on compressive strength were also performed. Throughout the study a correlation between pore structure and durability related properties is investigated. A comprehensive compilation of chloride penetration data is made and an empirical expression is derived for the prediction of long term diffusion coefficients. At the end of the investigation, limitations of the present study, conclusions and suggestions for future research are made.

Concrete is probably the most widely used construction material in the world. In the Arabian Gulf region, deterioration of concrete due to the aggressive environment is recognized to be the main factor affecting their structural integrity. The durability of concrete structures can be preserved by various protection methods; however, using cement replacement materials is one of the most effective and economic methods of maintaining their stability as well as extending their service life. The aim of this project is to study four interrelated aspects, namely, (1) the effect of hot environment on the properties of fresh concrete incorporating mineral admixtures, (2), the influence of exposure environment on the engineering properties of hardened concrete, under various curing conditions, without and with mineral admixture, (3), the differences in porosity and pore structure of the same set of mixes, and, (4) the effect of outdoor exposure on the durability-related properties of concrete. To achieve the above aims, the experimental programme involved the study of five different mixes of combinations of silica fume/slag and silica fume. The effects of real exposure to the Arabian Gulf environment of these mixes subjected to four curing regimes, namely, continuous water curing, no water curing after demolding, and air drying after 3 and 7 days of initial water curing were investigated. The properties investigated include (1) consistency and setting times of cement pastes, workability and workability loss with time, (2) engineering properties such as compressive strength, dynamic modulus of elasticity, pulse velocity, shrinkage, expansion and thermal expansion, (3) microstructural properties such as porosity and pore size distribution, (4) durability-related properties such as permeability, water absorption and carbonation depth. The results show that exposure to hot environment results in rapid setting times, faster loss of slump, higher porosity, coarser pore structure and more permeable concretes. It was found that part cement replacement by silica fume and slag improves the quality of concrete mixtures, refined the pore structure and produced concretes with very low porosity and continuous pore diameter in both indoor and outdoor environment. The properties of concrete containing mineral admixture appear to be more sensitive to poor curing than the plain concrete, with the sensitivity increasing with increasing amount of slag in the mixture.

Thèse Ecole polytechnique fédérale de Lausanne EPFL, no 4302 (2009), Faculté des sciences et techniques de l'ingénieur STI, Programme doctoral Sciences et Génie des matériaux, Institut des matériaux IMX (Laboratoire des matériaux de construction LMC). Dir.: Karen Scrivener.

Loosening of the cemented acetabular component of a total hip replacement is 2-3 times more common than femora stem failure. Cement keyholes drilled into the acetabulum have been recommended to improve this fixation but little is known of the optimum sizes and locations of these holes. This study investigated the diameter, depth and number of keyholes to be drilled to maximise the failure torque in a model system. A two-pronged approach was used; mechanical testing and finite element (FE) analysis. A Taguchi experimental design was used to identify the most significant factors and to predict the best configuration of keyholes within the constraints of the acetabular dimensions. One hole at each of the pubic, iliac and ischial sites, of 12 mm diameter and 6 mm depth, was found to be the optimum configuration. The failure torque was most strongly dependent on the hole diameter in the pubic region, decreased with increasing hole depth and was not sensitive to the number of holes. Both two dimensional and three dimensional FE analyses of a single cement keyhole showed that the lowest von Mises stress and the best distribution of shear stress was for the hole of 12 mm diameter and 6 mm depth. The results of the two approaches used here are in excellent agreement. The final stage of this study investigated the optimisation of the keyhole shape and the design of a suitable drill bit for surgical use.

Master of Agribusiness<br>Department of Agricultural Economics<br>Dustin L. Pendell<br>Sachse Family Angus is both a commercial and registered Angus cow-calf operation in Northeast Kansas and has been in operation since 1935. The end goal in mind is to provide quality female breeding seedstock to other beef producers with the hopes of improving their herds. Successful selection and development of beef replacement heifers have major long term effects on stayability in any herd and can even have a positive impact on the whole herd. The objective of this study is to create a decision tool to determine best heifer selection strategies. Specifically, taking a look at the cost of heifer development under a range of scenarios as it applies to more traditional heifer development. The depth of literature addressing the issue of buying or raising replacement heifers is vast, providing various degrees of analysis to help a producer make the best informed decision. Some economists would argue that no single aspect of beef production management is as complicated, or has such an economic impact as cow culling and replacement heifer decisions (Melton, 1980). Procedures and methods were created to analyze whether a producer should raise or develop their own replacement heifers. One method used in creating a decision tool is an enterprise budget. Enterprise budgeting is the systematic determination and listing of expected outputs, revenues, and costs due to the production processes required to produce one unit of an enterprise for a specified time period. To take this one step further, it is assumed a producer makes choices with respect to the combinations of productive factors and products. Partial budgets include an analysis of net returns from small changes or refinement to a ranch. It focuses on parts that change while building upon an enterprise budget. In essence, it fine tunes current operations while holding all else constant. The benefits of partial budgeting take a look at what will be the new or added revenue if a change is implemented on the ranch and what costs will be reduced or eliminated if taken place. What will be the new or added costs and what revenues will be reduced if a change takes place are also things to keep in mind. Therefore, the result will show a producer the net benefit of the change. In turn, Sachse Family Angus will use this information to build their registered and commercial replacement heifers either by developing their own or purchasing from other breeders. Overtime, this decision will be critical as it will impact their herd for years to come. In conclusion, maintaining a good sound, high functioning beef cow herd means selecting and developing quality replacement heifers to retain in the herd each year. An estimated 20% of heifers born each year at Sachse Family Angus are kept as replacement heifers. When managing home raised heifers or purchased heifers, maintaining costs and keeping them in check is crucial because they represent a large up-front investment. The bottom line of this research is to give the managers at Sachse Family Angus and other operations across the country a decision tool that can be used to analyze their current resources and the resources it will take to develop their own heifers successfully and in the most cost effective way or help them analyze if purchasing their heifers makes the most financial sense.

Continuous forest inventory (CFI) with partial replacement of sampling units (SPR) has been established as an efficient inventory technique. Previous CFI with SPR theory was based on equal probability sampling which might not be as efficient as the unequal probability sampling that is now widely used in forest inventories. In this study, the general theory of multistage sampling combined with CFI using unequal probabilities in a SPR structure on two occasions is discussed. Estimators of the current means and the change in means for both one-stage and two-stage cases are given, along with the estimators for the overall variances. The estimators derived for estimating the current means take the same form as those developed by other researchers. However, the estimators proposed for predicting the change in means take simpler forms than those presented in the literature. This might result in greater simplicity when used in data processing. The application of CFI with SPR using multistage unequal probability sampling to a Chinese national forest inventory is presented for illustrative purposes. Some particular points are addressed regarding specific situations in China. Although no precise theoretical demonstration of the gains from using this method is given, the combination of highly efficient sampling with unequal probabilities and the very practical multistage sampling in CFI with SPR inventories can certainly provide an efficient alternative to traditional Chinese inventory systems.<br>Forestry, Faculty of<br>Graduate

The lasting integrity of the bond between bone cement and bone defines the long-term stability of cemented acetabular replacements. Although several studies have been carried out on bone-cement interface at continuum level, micromechanics of the interface has been studied only recently for tensile and shear loading cases. Furthermore, the mechanical and microstructural behaviour of this interface is complex due to the variation in morphology and properties that can arise from a range of factors. In this work in vitro studies of the bone-cement interfacial behaviour under selected loading conditions were carried out using a range of experimental techniques. Damage development in cemented acetabular reconstructs was studied under a combined physiological loading block representative of routine activities in a saline environment. A custom-made environmental chamber was developed to allow testing of acetabular reconstructs in a wet condition for the first time and damage was monitored and detected by scanning at selected loading intervals using micro-focus computed tomography (μCT). Preliminary results showed that, as in dry cases, debonding at the bone-cement interface defined the failure of the cement fixation. However, the combination of mechanical loading and saline environment seems to affect the damage initiation site, drastically reducing the survival lives of the reconstructs. Interfacial behaviour of the bone-cement interface was studied under tensile, shear and mixed-mode loading conditions. Bone-cement coupons were first mechanically tested and then μCT imaged. The influence of the loading angle, the extent of the cement penetration and the failure mechanisms with regard to the loading mode on the interfacial behaviour were examined. Both mechanical testing and post failure morphologies seem to suggest an effect of the loading angle on the failure mechanism of the interface. The micromechanical performance of bone-cement interface under compression was also examined. The samples were tested in step-wise compression using a custom-made micromechanical loading stage within the μCT chamber, and the damage evolution with load was monitored. Results showed that load transfer in bone-cement interface occurred mainly in the bone-cement contact region, resulting in progressively developed deformation due to trabeculae bending and buckling. Compressive and fatigue behaviour of bovine cancellous bone and selected open-cell metallic foams were studied also, and their suitability as bone analogous materials for cemented biomechanical testing was investigated. Whilst the morphological parameters of the foams and the bone appear to be closer, the mechanical properties vary significantly between the foams and the bone. However, despite the apparent differences in their respective properties, the general deformation behaviour is similar across the bone and the foams. Multi-step fatigue tests were carried out to study the deformation behaviour under increasing compressive cyclic stresses. Optical and scanning electron microscopy (SEM) were used to characterise the microstructure of foams and bone prior to and post mechanical testing. The results showed that residual strain accumulation is the predominant driving force leading to failure of foams and bones. Although foams and bone fail by the same mechanism of cyclic creep, the deformation behaviour at the transient region of each step was different for both materials. Preliminary results of foam-cement interface performance under mixed-mode loading conditions are also presented.

Cement production produces a significant portion of CO₂ emission caused by human activity. The replacing of cement with alternative binders is one way to reduce the CO₂ emission from cement industry and to save natural resources. In Finland, approximately 500 000 tons of biomass fly ash is created annually. Part of this ash could potentially be utilized as a cement replacement material if current concrete standards are modified to allow the use of biomass fly ash as a raw material of structural grade concrete, but even under current legislation biomass fly ash could be already utilized in low value concrete and mortar products or applications. In this study, the suitability of two biomass fly ash, from bubbling fluidized bed combustion, to partially replace cement in concrete was investigated. Cement was replaced also by milled sand to identify the effects of fine inert material. Replacement levels of 10%, 20% and 40% were used. Research methods included a grinding of materials, the preparation of mortar samples, evaluation of fresh mortar paste, strength measurements, calorimetry, electron microscopy, X-ray powder diffraction analysis and chemical analysis. Results of the study demonstrated, that replacement of cement by biomass fly ashes or milled sand had a clear impact on the properties of fresh and hardened mortar. Both fly ashes involved the hydration of cement instead of acting just as a filler material. The chemical composition and performance of two studied fly ash differed greatly from each other and indicated that at least part of biomass fly ashes could be very potential alternatives to replace significant amounts of cement in concrete. On the other hand, some biomass fly ashes can also cause detrimental expansion when used in concrete<br>Sementin tuotanto on vastuussa merkittävästä osasta ihmiskunnan aiheuttamista CO₂ päästöistä. Sementin korvaaminen vaihtoehtoisilla sideaineilla on yksi keino pienentää sementtiteollisuuden CO₂ päästöjä sekä säästää luonnonvaroja. Suomessa syntyy vuosittain noin 500 000 tonnia lentotuhkaa biomassan poltosta. Osa tästä lentotuhkasta voitaisiin mahdollisesti hyödyntää sementtiä korvaavana raaka-aineena, mikäli nykyisiä betonistandardeja muutetaan tulevaisuudessa sallimaan myös biomassan poltosta syntyvät lentotuhkat betonin raaka-aineina. Nykyisessäkin tilanteessa biomassan lentotuhkaa voitaisiin hyödyntää matala arvoisissa betonituotteissa ja sovelluksissa. Työssä tutkittiin sementin osittaista korvaamista kahdella leijupoltosta peräisin olevalla biotuhkalla. Sementtiä korvattiin myös jauhetulla hiekalla eri vaikutusmekanismien selvittämiseksi. Tutkimuksessa käytettiin 10, 20 ja 40 % korvausasteita. Tutkimus metodit käsittivät materiaalien jauhamisen, kemiallisen koostumuksen analysoinnin, laastinäytteiden valmistamisen, tuoreen laastin ominaisuuksien arvioimisen, lujuusmittaukset, kalorimetrian, elektronimikroskopian sekä hydrataatiossa syntyneiden faasien määrityksen. Tutkimuksen tulokset osoittivat, että sementin osittainen korvaaminen biomassan lentotuhkalla tai jauhetulla hiekalla vaikuttaa selvästi tuoreen sekä lujittuneen laastin ominaisuuksiin. Molemmat tuhkat vaikuttivat sementin hydrataatioon sen sijaan, että ne olisivat toimineet ainoastaan hienona täyteaineena. Tuhkien kemiallinen koostumus sekä vaikutukset valmistettujen näytekappaleiden ominaisuuksiin poikkesivat toisistaan huomattavasti. Tutkimuksen perusteella ainakin osa biomassa lentotuhkista voisivat korvata huomattavia osia betonissa käytettävästä sementistä. Jotkut lentotuhkista voivat puolestaan aiheuttaa betonin haitallista paisumista mikäli niitä käytetään sementtiä korvaavana ainesosana

With time, the rate of symptomatic acetabular component loosening accelerates and overtakes that of the femoral component as the principal reason for the revision of total hip replacement. In the femur extensive study has shown that cement pressurisation and good preparation of the bone bed improves the survival rate, but acetabular fixation requires further investigation. Production of cement pressure in the acetabulum is anatomically difficult. Pressurisation with conventional and novel designs of cement pressurisers has been compared to manual techniques and component insertion. The pressurisers increased peak and mean pressures and pressure duration. Finite element modethng of cup insertion showed that flanges and higher insertion rates increased cement penetration into cancellous bone. Per-operatively, one design of pressuriser produced cement pressures comparable to those found in the laboratory. Structural finite element modelling of the natural hip indicated that the subehondral plate and the relatively dense cancellous bone supporting it distribute the joint contact force into the medial and lateral pelvic cortices. A perfectly bonded cemented polyethylene cup stiffened the acetabulum so that more load was transferred directly to the cortices at the acetabular rim, with consequent interface stress concentrations. However, complimentary experimental studies using a dynamic joint simulator and a servo-hydraulic materials testing machine suggested that perfect fixation between cement and bone at the rim was not possible, even under laboratory conditions. Debonding of the cement bone interface at the rim, where dense bone prevents cement interdigitation, allowed micromotion. Since the clinical mechanism of failure of the acetabular component appears to be progressive debonding, from rim to apex, of the cement-bone interface, these studies support the initiation of the failure mechanism by mechanical factors, which may then allow the ingress of wear debris. The experimental studies suggested that the use of pressurisers reduces the amount of micromotion and thus may improve the long term stability of the interface.

This thesis presents a study of the bond strength between corroded and uncorroded steel reinforcement and the surrounding concrete within steel reinforced structures. The work is based on concretes manufactured with different types of cement replacement materials, and investigates the influence of the corrosion rate of steel as predicted by concrete permeability. The cement replacement binders included CEM II, blended cements of fly ash (PFA), ground granulated blast-furnace slag (GGBS), metakaolin (MK) and silica fume (SF). The experimental work was conducted by placing 200mm cube test specimens in a saline solution (3.5% NaCl) for different exposure times (3, 7, 10, 14 and 20 days) with an applied external current of 10 mA between the reinforcing steel and a stainless steel counter electrode. Pull-out tests were conducted to evaluate the bond strength between the concrete and the steel reinforcement. The permeability coefficients of concretes were investigated using a relative gas permeability test. The specimens used for determining permeability were cylindrical 100mm diameter and 100mm length, which were oven dried at 105 ºC. The experimental results indicated that the bond strength was governed by concrete properties. Furthermore, the bond strength of the corroded specimens was found to depend on the corrosion levels and varied across all concrete types, depending on the concrete microstructure. Moreover, when the corrosion level exceeded 1.74%, the bond strength began to decline. Thereafter, the bond strength continued to reduce as the corrosion time of the reinforced concrete increased. The relationship between the compressive strength and gas permeability of concretes was inconclusive but the latter does depends on the cement replacement levels. The PFA concretes had the lowest permeability compared to the other two types of concrete (CEM II and GGBS). The permeability of concretes and corrosion rates with different types and levels of cement replacement materials significantly decreased as the age of concretes increased. The improvements in gas permeability and corrosion rate were observed when 40% of cement weight was replaced with PFA. The ABAQUS program was used to model the bond-slip behaviour of different concrete mixes, in addition to a plastic damage model. A cohesive zone element was employed for the steel-concrete interface. During analysis, the numerical model was validated against the results obtained from the experimental tests. The numerical results showed good agreement with the experimental results for CEM II, GGBS and SF concrete specimens, but in the case of PFA concrete where the numerical result of bond strength was overestimated by to the experimental ones.

Concrete plants consume 10 billion tons of natural aggregates annually from quarries and gravel plants for produce concrete, this demand requires exploiting natural resources from mountains and rivers producing an ecological imbalance. One solution is to use Palm Oil Clinker (POC), which is eliminated in large quantities in the dumps and rivers without taking advantage of its puzolanic, binding and resistance properties as an aggregate in the concrete; another alternative is to apply rubber from abandoned and discarded tires as waste in landfills or burned, without taking advantage of its performance of improvement in concrete, increasing its resistance to impact and fatigue. Unable to find joint POC and rubber information, this research studies its influence replacing 2.5% rubber (grained and crushed) with 10%, 12.5% and 15% POC in the fine aggregate on traditional concrete; results indicate that with 12.5% of POC as the ideal percentage, the compressive strength, tensile strength and flexural strength rise between 2.16 - 9.54%, so the concrete obtained has a cost of less than 4.09% and has 3.65% less CO2 emission.

Reinforcement corrosion has been identified as the predominant deterioration mechanism for reinforced concrete structures (fib, 2006), and is usually caused by carbonation or chloride attack. Chloride- induced corrosion is triggered by an increasing concentration of chloride ions in the pore solution. Corrosion seriously affects the serviceability and safety of concrete structures, and can cause major maintenance costs. Therefore, precise information and understanding of chloride ingress and chloride binding may enable better prediction of service life of concrete structures. The aim of this study is to gather information on chloride binding capacity of supplementary cementitious materials and its effect on chloride profiles. The use of fly ash and ground granulated blast furnace slag are known to increase the binding capacity thus lowering the free chloride content available for corrosion initiation. This can most likely be linked to a high alumina content in which chemical binding capacity increases. Additionally, blast furnace slag and fly ash can increase the formation of C-S-H which enhance the physical binding capacity. The effect of chloride binding on chloride ingress was investigated in addition to the binding capacity of fly ash cement and blast furnace slag cement. Chloride binding isotherms and chloride profiles were determined for mortars with w/c= 0.4 and 6% silica fume addition. Ground granulated blast furnace slag (50%) and fly ash (30%) were included as partial replacement for Portland cement. A variant of the equilibrium method was used to determine the chloride binding isotherms. Hydrated samples were grounded and exposed to solutions of CaCl2 and NaCl of varying concentrations at 20&#176;C. The determined binding isotherms were used to calculate bound and free chloride profiles for mortars exposed to NaCl for 6 months. The obtained results agree with much of the present literature. Small standard deviations and clear trends indicate reliable experimental data. One of the findings of the study is that various cementitious materials exhibit different binding capacities. Of the three tested mortars, the mortar with blast furnace slag resulted in the highest binding capacity followed by the fly ash blended cement. Ordinary Portland cement (OPC) had the lowest binding capacity. A non- linear relationship between free and bound chlorides were found, in which the Freundlich and Langmuir isotherm provided a good fit. Due to varying binding capacities, it follows that binding should be included when comparing chloride ingress in various binders. Chloride profiles were produced in order to evaluate the effect of binding on chloride profiles. The high binding capacity of the ground granulated blast furnace slag cement resulted in a lower amount of free chlorides in the pore solution. It appears as the binding isotherm determined by CaCl2 gives a better reflection of the binding behavior compared to the NaCl binding isotherm. Generally, the apparent diffusion coefficient is determined by fitting of total chloride profiles to the solution of Fick&#146;s 2nd law of diffusion. The approach is questionable as it rests on number of simplifying assumptions that rarely are met in a real structure. It seems more appropriate to base the fitting on free chlorides, as only the free chlorides are influenced by diffusion. Therefore, the apparent diffusion coefficient and the surface concentration were determined by fitting of both total and free chloride profiles. The results proved that the coefficient is reduced by 28 - 35 % if binding is included.

Prior to the implementation of the European Union Urban Waste Water Treatment Directive (91/271/EEC) in 31 Dec 1998, around a quarter of the sewage sludge produced in the UK was either discharged to surface waters via pipes or disposed from ships at sea. Discontinuing this route together with the quality requirements of the European Waste Water Directive, led to the generation of significant quantities of sewage sludge. It has therefore become required to treat this waste effectively before it can be sent back to the environment. Consequently, this added greater challenges for the environmental agencies, as well as local authorities. The treatment process comprises costly and energy consuming applications including physical, chemical, biological and thermal. In addition to the sewage sludge, the power generation industry produces massive quantities of fly ash from burning coal. In the UK, there is about 5,300,000 tonnes of fly ash that are generated annually, which require to be processed and classified in order to meet the standard requirements before it can be used in the construction applications. The classifying process also involves a series of costly and energy consuming mechanical and physical applications. This research programme has introduced an innovative alternative to the traditional re-use and disposal routes of Raw Sewage Sludge (RSS) and unprocessed fly ash. It has suggested the utilisation of RSS and unprocessed fly ash as raw ingredients for the production of sustainable construction materials. This research programme has therefore examined the performance of cement-based materials containing Raw Sewage Sludge (RSS) as a water replacement and unprocessed fly ash as cement replacement. Mortar and concrete mixes incorporating these materials were tested for their flowability/workability, density, Total Water Absorption (TWA), Ultrasonic Pulse Velocity (UPV), compressive strength, flexural strength, drying shrinkage, sulphate attack and leaching properties. Three series of cement-based materials were studied including mortar mixes with RSS and unprocessed fly ash (Series 1), mortar mixes with RSS and large proportions of unprocessed fly ash (Series 2), and concrete mixes with RSS and unprocessed fly ash (Series 3). The outcomes of the investigation were encouraging in that cement-based materials containing RSS and unprocessed fly ash that were produced demonstrated relatively good engineering, durability and environmental properties in comparison to the control mixes. The inclusion of unprocessed fly ash significantly reduced flowability/workability; however it improved long-term compressive strength for both mixes with RSS and water. The best compressive strength results were recorded when cement was replaced with 10-20% unprocessed fly ash by weight of total binder. The results also showed that sulphate attack resistance improved when fly ash was included. Moreover, safe concentration levels of heavy metals and free ions were detected when leaching test was performed. However, it must be kept in mind that more environmental tests must be performed before any large scale use is undertaken.

The bricks are one of the primary materials required for construction of homes that no used completely when executes all the walls due, the excess purchase, the cutting to be settle, the breaking for their transfer and its fixed dimensions; this situation requires monitoring on work site the order, cleanliness and accidents. A common practice is these bricks and/or waste are included in the clearing construction before being deposited or eliminated in dumps or sanitary landfills, with their early clogging and shortening them to ther design lifespan. An important alternative to reduce this waste, is to recycle them and reuse them as a concrete component material, due to their high absorption percentage that allows them to keep the water inside of them and then use it in the cement hydration process as internal curing of the concrete. In the present investigation, the effect of crushed clay brick as a replacement for coarse aggregate in concrete processing is studied. The results indicate that with 21 % replacement brick, the plastic contraction decreases, and the compressive strength and flexural strength increase.

Thesis (MScEng)--Stellenbosch University, 2013.<br>ENGLISH ABSTRACT: The aim of this research is to investigate the potential use of coarse recycled concrete aggregate (RCA) as a material in structural concrete. The lack of knowledge and specifications in South Africa are the main reasons for this research of RCA. By increasing the database of research of RCA in South Africa the possibility of specifications for this alternative building material can be initiated. The implications of such specifications would lead to RCA acceptance in concrete design and therefore reducing the amount of construction and demolition (C&D) waste accumulating at landfill sites and decreasing the extraction of depleting natural aggregates. The objectives that are achieved through this research project are firstly, what is the percentage replacement of RCA to a concrete blend that will produce a material that achieves similar or better results than a concrete blend containing natural aggregates. Secondly, what aggregate properties and limits should be defined in the specification of RCA for it to be accepted as a material in concrete mixtures. The objectives were assessed through examining the geometrical, physical and chemical properties of the aggregate as a material and the fresh and hardened concrete properties of concrete which contains RCA as a constituent. RCA which was processed by a commercial recycling facility which produces concrete masonry units was collected at three different instances. This material was reprocessed in the laboratory to control the grading and amount of fine material not guaranteed by the recycling process. The RCA is then combined with natural aggregate (NA) at the replacement percentages: 0, 15, 30, 50 and 100% which is then used to examine the aggregate properties. It was determined that the physical properties of RCA were dependent on the geometrical properties, while taking into consideration that the geometrical properties are dependent on the source and method of recycling of the original C&D waste. The chemical properties were established as dependent on the physical properties of the RCA. The RCA is then mixed with NA at the same replacement percentages together with other concrete constituents to produce the concrete used to examine fresh and hardened concrete properties. The fresh concrete properties investigated were: slump, slump loss, air content and fresh compacted density. The hardened concrete properties studied were: compressive strength, tensile splitting strength, oxygen permeability, water sorptivity, chloride conductivity, modulus of elasticity, shrinkage and creep. The concrete properties were not significantly influenced by the inclusion of RCA. According to the aggregate and concrete properties examined in this investigation, the full replacement of NA in structural concrete is possible and will improve the sustainable development of the construction industry.<br>AFRIKAANSE OPSOMMING: Die doel van hierdie navorsing is om ondersoek in te stel na die potensiele gebruik van growwe herwonne betonaggregaat (RCA) as ‘n materiaal in betonstruktuurontwerp. Die gebrek aan kennis en spesifikasies in Suid Afrika is die vernaamste rede vir hierdie navorsing van RCA. Deur die vermeerdering van die databasis van hierdie navorsing van RCA in Suid-Afrika kan die moontlikheid van spesifikasies vir hierdie alternatiewe boumateriaal geïnisieer word. Die implikasie van sodanige spesifikasies sou lei tot RCA aanvaarding in betonontwerp en dus die vermindering van die hoeveelhede konstruksie en sloping (C&D) van afvalversameling by stortterreine en om die ontginning van natuurlike aggregate te verminder. Die doelwitte wat deur hierdie navorsingsprojek bereik word is eerstens, wat is die vervangings persentasie van RCA in 'n betonmengsel wat produseer word wat dieselfde of beter resultate sal lewer as 'n betonmengsel wat uit natuurlike aggregate bestaan. Tweedens, watter aggregaat eienskappe en beperkings moet gedefinieer word in die spesifikasie van RCA sodat dit aanvaarbaar is as ‘n materiaal in betonstruktuur ontwerp. Die doelwitte word geassesseer deur die ondersoek van die geometriese, fisiese en chemiese eienskappe van die aggregaat as ‘n wesenlike materiaal en die vars en verharde betoneienskappe van RCA as ‘n bestanddeel in struktuurbetonontwerp. RCA monsters was geneem by ‘n kommersiele herwinningsfasiliteit wat RCA gebruik om betonsteen eenhede te vervaardig, is op drie verskillende tydperke ingesamel. Hierdie materiaal is herverwerk in die laboratorium om die gradering en die hoeveelheid van fyn materiaal wat nie deur die herwinningsproses beheer is nie. Die RCA was dan gekombineer met NA teen vervangingspersentasies van: 0, 15, 30, 50 en 100 % wat dan gebruik was om die eienskappe van die aggregaat te ondersoek. Daar is vasgestel dat die fisiese eienskappe van die RCA afhanklik van die geometriese eienskappe, met inagneming dat die geometriese eienskappe afhanklik is van die bron en metode van die herwinning van die oorspronklike C&D afval. Dit is gestig dat die chemise eienskappe is afhanklik van die fisiese eienskappe van die RCA. Die RCA is toe gemeng met NA teen dieselfde vervangingspersentasies saam met ander beton bestanddele om beton te produseer wat dan vergelyk kan word met vars en verharde beton eienskappe. Die volgende vars betoneienskappe is ondersoek: insinking, insinking verlies, luginhoud en vars gekompakteerde digtheid. Die volgende verharde betoneienskappe is bestudeer: druksterkte, trek die splintsing van krag, suurstofpermeabiliteit, water sorptiwiteit, chloride geleidingsvermoё, modulus van elastisiteit, krimp en kruip. Die beton eienskappe was nie beduidend beïnvloed deur die insluiting van RCA nie. Volgens die aggregate en beton eienskappe wat in hierdie navorsing ondersoek is, blyk dit dat die volle vervangingswaarde van NA in strukturele beton moontlik is en die volhoubare ontwikkeling van die konstruksiebedryf sal verbeter.

Hip resurfacing arthroplasty has changed the treatment of end stage arthritis without severe deformity for young, active adults. Presently, there are varying clinical approaches to implant design selection and cementation techniques. The purpose of this project is to determine what amount of reamer-femoral component offset allows for the best cement penetration into the femoral head. Rapid prototyped femoral component models were produced with reamer femoral component offsets of 0.0 mm, 0.5 mm, and 1.0 mm. After implantation onto models of reamed femoral heads made from high-density open-cell reticulated carbon foam, cement penetration was assessed from cross-sections of the foam-implant unit. Increased offset was found to decrease the extent of cement over penetration from the dome and chamfer. Increased offset also yielded optimal cement penetration as measured from the walls. Finally, increased offset was found to increase the height of cement mantle formation while maintaining complete seating of all implants.

The performance of a maltodextrin gel as a replacement (25, 50, 75, and 100%) for shortening along with high-fructose corn syrup-90 (HFCS-90), adjusted for sweetness in each treatment, were evaluated in a high-ratio white-layer cake formulation. Two controls were used to compare to fat-replaced cakes: control A (100% fat with 100% sucrose) and control B (100% fat with 50% sucrose/50% HFCS-90), which closely matched the sugar system of the fat-replaced cakes. Objective tests indicated that treatments D (50%), E (75%), and F (100%) had significantly higher (P<0.05) batter specific gravity values compared to both controls. Batter specific gravity, however, only significantly decreased (P<0.05) the volume of treatment F. Crust and crumb L and b values, indicated that control B produced a dark crust (P<0.05) with a light crumb (P<0.05), while treatment E produced a light crust (P<0.05) and treatment F a darker crumb (P<0.05). Treatment F produced a firm cake (P<0.05) with significantly (P<0.05) high percent moisture. Overall, no significant differences (Pâ⠰¥0.05) in water activity were found among treatments over time; in contrast, degree of staling significantly increased (P<0.05) over time for all treatments. Sensory results indicated that treatment F produced a significantly (P<0.05) moister, shorter, less adhesive and cohesive cake. Tenderness and sweetness scores indicated that treatments E and F were significantly (P<0.05) tougher and less sweet, respectively, when compared to the other treatments. Results from physical and sensory tests indicated that the combination of a maltodextrin gel and HFCS-90, up to 75% shortening replacement, resulted in satisfactory cakes.<br>Master of Science

This work is focused on a solving of problems regarding a total hip replacement with a fractured femur. The fracture is located in the distal end of the total joint replacement stem and the fracture is spreading in the proximal direction on the boundary of the bone and cement. A proximal part of femur is reinforced by fixing tape. There is also briefly described how computer models were carried out. Furthermore a stress - strain analysis of solved system has been performed in this work. The solution was realized using the finite element method in computational program ANSYS Workbench. Different variants with change of a fracture range and number of fixing tapes were considered during the solving. Stress - strain analysis shows that due a application of fourth fixing tape occurs lowering of main stresses values in the femur in fracture region. Simultaneously occurs a reduction of Equivalent stress values on a distal part of stem.

Stockholm Vatten has decided to close down the Bromma waste water treatment plantand manage the waste water from Bromma together with the waste water from the formerEolshällsverket to Henriksdal’s waste water treatment plant. Henriksdals wastewater treatment plant will be expanded for higher purification requirements and loads,estimated to be finished until 2040. This entails extensive renovations and additionsto the existing treatment plant in and on Henriksdalsberget, as well as a major expansionof the Sickla plant.The purpose of the study is to investigate an environmentally friendly alternative tothe standard concrete that will be used for the expansion of the Sickla plant. The largestenvironmental villain in concrete is the cement. The aim of this study has beento replace the cement with environmentally friendly additives in the largest possibleamount, thus reducing the negative impact of the cement on the environment.In the present study, a review was made of obtained data with exposure classes, then aliterature study was performed to gain knowledge in the area. With help from experts,two fictitious recipes for each exposure class have been calculated for the standardconcrete and the green concrete. In this way, a careful comparison between the concretetypes was made of the cement’s impact on global warming. Thereafter, a study wascarried out on existing EPDs, which were incorporated into the One Click LCA (2015)software. An LCA in the mentioned software was carried out, which enabled data to becompiled and a comparison of the climate impact between the four different fictitiousrecipes has been done.Compiled and compared data from LCA and analysis of EPDs show that 70% of thestructure with exposure class XD2 gets a 47% reduction in global warming when usinggreen concrete instead of standard concrete. Furthermore, the results show that theremaining 30% of the structure with exposure class XF3/XC4 gets a 20% reductionwhen using green concrete instead of standard concrete. The total reduction in globalwarming when using green concrete instead of standard concrete for the expansion ofSickla treatment plant was calculated to be 40%.<br>Stockholm Vatten har beslutat att lägga ned Bromma reningsverk och leda avloppsvattnetfrån Bromma tillsammans med avloppsvattnet från det forna Eolshällsverkettill Henriksdals reningsverk. Henriksdals reningsverk ska byggas ut för högre reningskravoch belastningar beräknade till år 2040. Detta medför omfattande om- och tillbyggnationeri det befintliga reningsverket i och på Henriksdalsberget samt en storutbyggnad av Sicklaanläggningen.Syftet med detta arbete är att undersöka ett miljövänligare alternativ till standardbetongensom ska användas vid utbyggnaden av Sicklaanläggningen. Då den främsta”miljöboven” i betongen är cementet har målet med denna studie varit att ersätta cementetmed miljövänliga tillsatsmaterial i största möjliga mängd, i syfte att minskacementets negativa inverkan på miljön.I föreliggande arbete har en genomgång utförts på erhållna data med exponeringsklasser,därefter påbörjades en litteraturstudie i syfte att inhämta kunskaper inomområdet. Med hjälp av experter har två fiktiva recept för respektive exponeringsklassräknats fram för standardbetongen och den gröna betongen. Med denna metod genomfördesen noggrann jämförelse mellan de olika recepten avseende cementets inverkanpå den globala uppvärmningen. Därefter undersöktes existerande EPD:er, vilka infogadesin i programvaran One Click LCA (2015). En LCA i den nämnda programvaranutfördes, vilket möjliggjorde att data kunde sammanställas och en jämförelse av klimatpåverkanmellan de fyra olika fiktiva recepten kunde genomföras.Sammanställd och jämförd data från LCA och analys av EPD:er visar att 70% av konstruktionenmed exponeringsklass XD2 får en reducering på 47% på den globala uppvärmningenvid användning av grön betong istället för standardbetong. Vidare visarresultatet att resterande 30% av konstruktionen med exponeringsklass XF3/XC4 fåren reduktion på 20% vid användning av grön betong istället för standardbetong. Dentotala reduktionen på den globala uppvärmningen vid användning av grön betongistället för standardbetong för utbyggnaden av Sickla reningsverk beräknades till 40%.

When hollow concrete masonry is used for construction in high seismic regions, structural designs typically require fully grouted walls. The grouting process is labor-intensive, time-consuming and has a high energy demand due to requirements of consolidation in each and subsequent grout lifts. Self-consolidating grout with admixtures has been successfully used without segregation in walls of up to 12.67 ft. in height. Investigation of self-consolidating grout mixes without admixtures has potential for sustainability improvement. This thesis reports on the compression strength and consolidation observations of self-consolidating characteristics of no vibration/no admixture grout made by substituting various proportions of Portland cement with Type F fly ash and/or ground granulated blast furnace slag (GGBFS). The percentages of Portland cement replacement evaluated were 0%, 50%, 60%, and 70% for Type F fly ash. The percentages of Portland cement replacement evaluated were 0%, 60%, 70% and 80% for Type F fly ash and GGBFS. Grout compressive strengths were evaluated from individually filled grout specimens constructed in concrete masonry hollow core units, dry cured, and tested after 7, 14, 28, 42, 56, and 130 days. Also, hollow concrete masonry walls were built 12.67 ft. tall and grouted. The relative performance was assessed by comparing to conventional grouted masonry and evaluating consolidation characteristics around mortar fins and reinforcement; compressive strength tests after 130 days of curing, and rebar pull-out tests were taken from various wall heights. All experimental grouts had acceptable consolidation characteristics but fly ash replacement grouts did not meet the compressive strength requirements.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.<br>Includes bibliographical references (p. 24).<br>The existing windows of the 90-year-old buildings on the main MIT campus are not energy efficient and compromise comfort levels. The single panes of glass allow too much heat transfer and solar heat gain. In addition, the steel framework has warped due to oxidation and decay of the glazing compound, resulting in air and water infiltration. This thesis explored a feasible solution of a partial window replacement that would not compromise the historical significance of the existing windows. The design and prototype demonstrated the replacement's functionality and preservation of aesthetic quality. The analysis showed an expected decrease in energy consumption of more than 70% and cost savings of nearly $2 million a year. The analysis also showed that comfort levels are higher throughout the year.<br>by YunJa Chen.<br>S.B.

The purpose of this study was twofold: 1) to identify commercially available feeds that could serve as suitable replacements for newly hatched Artemia in the diets of L. vannamei from Z3/M1 to PL10 without significantly affecting survival, final length and weight, and quality of the larvae and 2) to identify an ideal substitution rate between live Artemia and a replacement feed that maximizes feed and labor costs savings, survival, and PL quality. In Experiment 1, two commercially available Artemia replacement feeds, Zeigler EZ Artemia and Bernaqua Vitellus, were administered according to manufacturer’s guidelines in order to identify which feed served as a more suitable replacement diet. In Experiment 2, the more successful feed from Experiment 1 was administered in three different co-feeding strategies, in which the inert feed replaced a certain percentage of live Artemia. Mean percent survival was not significantly different between the Control, EZ Artemia, and Vitellus treatment groups in Experiment 1 (P<0.05). Both the EZ Artemia and Vitellus treatments yielded significantly different final mean lengths (mm) and weights (mg) from the Control group. The Vitellus feed results for all performance factors (mean percent survival, final length (mm), final weight (mg), and percent stress test mortality) were not significantly different than those of the EZ Artemia treatment, despite receiving no Artemia during the culture period, while the EZ Artemia treatment received 75% Artemia from PL5-PL10. For these reasons, the Vitellus feed was selected as the more successful feed in Experiment 1. In Experiment 2, there was no significant difference between the four treatment groups (Control, V50, V100/50, and V100/75) for mean percent survival and percent stress test mortality (P<0.05). The V100/50 and V100/75 treatments’ mean final lengths (mm) and weights (mg) were significantly different than those of the Control treatment. There were no significant differences between the V50, V100/50, and V100/75 treatments for any of the observed performance factors. These results indicate that the maximum substitution rate of Vitellus for Artemia in this experiment (the V100/75 treatment) was successful in replacing 84.33% of newly hatched Artemia in the larval culture of L. vannamei from Z3/M1-PL10 without resulting in significantly different survival and stress test mortalities compared to the Control group. Feeding schedules such as V100/75 treatment help streamline production efforts in commercial operations and result in increased production cost savings when compared to other replacement feeding schedules that begin in the early mysis stages. The V100/75 feeding schedule influences variable feed and labor costs the greatest because farmers are able to delay the culturing of Artemia an additional 7 days (until PL5) from what is typically performed in larviculture facilities.

As well as reducing the level of protein in feeds, the strategy of replacing fishmeal with alternative protein sources may be an effective approach towards reducing costs and offering more sustainable feeds for aquaculture. Within the framework of this study, four trials were conducted to evaluate the nutritional potential of selected animal by-products, namely: Poultry Meat Meal (PMM), steam Hydrolysed Feather Meal (HFM), Enzyme treated Feather Meal (EFM) and Spray Dried Haemoglobin (SDH), as pat1ial substitutes for fishmeal in the diet of gilthead sea bream. The research strategy employed followed a two phase scheme which consisted of determining ingredient restrictions in the first place and validating subsequent formulations on the biological performances of the fish in the second place. Ingredient restrictions were related to nutrient specification, digestibility and palatability, whereas biological performances of the fish were assessed in terms of growth response, feed utilization, nutrient assimilation, tissue integrity and composition as well as basic health status. Using a classical experimental design for the dete1mination of apparent digestibility coefficients (ADCs), 8 diets (made with the individual ingredients plus 3 blends) were tested in trial I. This trial demonstrated that protein and energy of PMM and SDH were highly digested by gilthead sea bream (80%) whilst protein ADC. for the feather meals were much lower (22-23%). It was moreover observed that processing feather meal with an enzymatic treatment did not yield any significant benefit over the standard steam hydrolysed method, and that combining feather meals with blood meal was clearly not advantageous. This preliminary investigation also yielded valuable numerical ADC for essential amino acids (EAA), revealing In some cases significant discrepancies with regard to the overall protein digestibility (e.g. isoleucine: 54%, and methionine: 60% in SDH). In the second trial, six iso-energetic/iso-nitrogenous diets were formulated on a protein digestibility basis to test various inclusion rates of PMM, SDH and EFM over a period of 9 weeks. In comparison to the fishmeal reference diet, results indicated that diet with a 25% replacement of fishmeal by PMM was effective in supporting the growth of gilthead sea bream (SGR: 1.78%) and conve1iing feed into body weight (FCR: 1.33) (P&lt;0.05). Higher inclusion rates of PMM resulted in lower performance, but moderate inclusions of SDH and EFM were equally shown to be feasible without impairing fish productive values. These findings were further supported by histological and haematological assessments which provided evidence that such inclusions did not disrupt gut integrity, create anaemia conditions (P&lt;0.05) or affect the physiological function of the liver. On the basis of trial 3 it was apparent that palatability of PMM could represent one of the main factors limiting the inclusion of this commodity in the diet for gilt head sea bream (daily feed intake/unit of time measured at 3.3g/min tor fishmeal and 2.6g/min for PMM). Finally, in accordance with the measurements of lipid inclusion in hepatocytes (trial 2) and the fatty acid analysis of the carcass (trial 4), it is believed that the high lipid content of PMM could represent further argument toward the limitation or dietary PMM incorporation as long as a high quality product is desired. From this study it is concluded that practical diets li)r gilthead sea bream would greatly benefit in terms of both nutrition and economics from adequate inclusions (considering specific ingredient restrictions) of animal by-products.

The purpose of this research was to incorporate a potato product into bread as a partial replacement for wheat flour and to describe a collaborative process for the development of bread products in three Soviet communities. Six potato flake breads and six cooked-mashed potato breads, with and without added gluten, were evaluated in a pilot study. Consumer acceptance scores indicated no significant differences among the twelve bread products. Four bread products, 29% and 45% cooked-mashed potato breads without added gluten, 15% potato flake bread with added gluten, and a 100% wheat flour bread, were selected for objective measurements, descriptive sensory evaluation, and central location acceptance testing. The four breads were not significantly different in the objective measurements of standing height, percent protein and amino acid content The three potato breads had the highest moisture percent loss on day 1. Texture analysis indicated the 45% bread had the highest texture measurements from the day of baking through day 4. The control "rapid" bread had the lowest analysis of freshness measurements. Staling, as measured by differential scanning calorimetry, indicated the potato breads had significantly reduced staling rates when compared to 100% wheat flour bread. Eleven trained panelists judged ten characteristics of the control and potato breads. The panelists perceived the potato breads to be more moist than the control. The other sensory characteristics of the control and potato breads were judged as similar. Central location acceptance testing in Alaska and the Soviet Far East indicated that the potato breads were acceptable and consumers indicated they would buy the breads if they were available. Across all locations the locally purchased control bread was liked significantly less than the potato breads. A collaborative process was designed for development of food products in Soviet and Alaskan communities.<br>Ph. D.

The food industry has responded to the American Heart Association's overwhelming concerns about the complications of obesity with an array of fat reduced products that maintain the functionality of fat in given systems. In baked products, it appears that no one single ingredient effectively mimics these functions. The present study investigated the effect of liquid or dry honey as a partial replacement for sugar on the baking and keeping qualities of fat reduced muffins. The fat reduced muffins also utilized a hydrocolloid fat replacer, bacterial and fungal amylases, and an emulsifier (DATEM). Results showed that both liquid and dry honey significantly (p<0.05) increased crust and crumb color at all replacement levels, however the use of 25% liquid honey was shown to favorably increase the crust color of fat reduced muffins. Volume was not significantly (p>0.05) affected but appeared to decrease with the addition of honey due to either premature starch gelatinization or a decrease in batter pH. The addition of honey increased moisture content, and decreased water activity, but did not decrease firmness or staling rates especially after prolonged frozen storage. Sensory panelists noted that the addition of liquid or dry honey increased the cohesive forces and decreased tenderness. The addition of moisture to the fat reduced system did not appear to improve the perceived moistness of the product.<br>Master of Science

Organic soils present a difficult challenge for roadway designers and construction due to the high compressibility of the soil structure, the often associated high water table, and the high moisture content. For other soft or loose soils (inorganic soils), stabilization via cement or similar binders (a method called soil mixing) has proven to be an effective solution. To this end, the Federal Highway Administration has published a comprehensive design manual for these techniques. Organic soils, however, are not addressed therein to a level of confidence for design, as organic soils do not follow the trends of inorganic soils. This has been attributed to the high porosity, high water content, and high levels of humic acids common to organic soils. This thesis presents the findings from a literature search, laboratory bench tests, large scale laboratory tests, and concludes with recommendations for design involving soil mixing applications in highly organic soils. Laboratory tests (bench tests) were performed to assess the effect of cementitious binder type, binder content, mixing method, organic content, and curing time on strength gain. This phase involved over 500 test where in all cases, specimens with organic content higher than approximately 10% required disproportionally more cement for the same strength gain when compared to inorganic or low organic content samples. Using the findings of the bench tests, a 1/10th scale test bed was built in which soil containing approximately 44% organics was placed and conditioned with rain water. The dimensions of the bed accommodated three side-by-side tests wherein dry and wet soil mixing were performed each on one third of the bed. The remaining third of the bed was left untreated. Load tests were then performed on the three portions of the bed where the load for a simulated roadway was placed. These loads were left in place for several weeks and monitored for movement. Results showed improvement for the treated portions relative to the untreatment with virtually identical response coming from both dry and wet methods (both used identical amounts of cement per volume). The findings of this thesis suggest that the adverse effects of organic soils can be combatted where more cement content is required to bring the water / cement ratio down to acceptable levels and even more cement is required to offset the acidity. While this has been a recurring observation of past researchers, a cement factor threshold was defined by experimental data below which no strength gain was achieved. This threshold was then defined as a cement factor offset above which the measured strengths matched well with other soil types. As a result, a recommended approach for designing soil mixing applications in organic soils was developed.

Soft soils are deposited globally, especially in estuarine or coastal areas. In recent years, the land resource has lessened due to rapid urbanisation and population growth around the globe. It is crucial to develop land on poor ground conditions to solve the issue of land shortage due to urbanisation. South East Queensland is a particular region where soft soils are widely deposited. More construction is expected to be carried out on its soft soil deposits as the urbanisation continues. However, the existence of soft soils can cause construction complications because of the following reasons: having high compressibility and water content, accompanied by low shear strength and permeability. Therefore, the study of the mechanical behaviour of reconstituted and stabilised soft soils is significant in geotechnical engineering practice. There are limitations in previous research regarding the properties of soft soils. For example, the common particles in soft soils are clay, silt, and sand particles. The behaviour of clay and sand particles are unique and easy to identify. However, the behaviour of silt particles lies in between the behaviours of clay and sand. It is important that some previous studies found that the behaviour of silt is not in accordance with the critical-state framework adopted for clay and sand. It is suggested that the behaviour of silts is a transitional form between clay and sand. Some silts exhibit sand-like behaviour, while some exhibit clay-like behaviour. Consequently, it is important to understand silt’s physical, mineralogical, strength and microstructural behaviour, as it is presently recognised that gaps in understanding its fundamental behaviour exist. In addition, soft soils need to be stabilised by suitable ground improvement techniques before any structure can be safely constructed on it. It is widely known that in-situ soil mixing or stabilisation (e.g., mass mixing or deep soil mixing) has been proven to be an effective ground improvement technique in improving the engineering properties of soft soils. Cement is one of the commonly used cementitious materials which can be used to treat soft soil in the application of in-situ soil mixing. It can increase the soil mix strength and decrease the water content by triggering the hydration of cement and pozzolanic reactions. The use of cement to stabilise soft soils and the behaviour of cement-stabilised soils has been extensively investigated in many previous studies. However, the use of cement can cause environmental issues as the production of cement results in high emissions of carbon dioxide (CO2). Hence, it is essential also to consider other suitable types of stabilisation additives to reduce the amount of cement used in the stabilisation of soft soil. Fly ash and a commercially available additive DuraCrete, were investigated in this study as partial replacements of cement. The behaviour of specimens stabilised by cement, fly ash-blended cement, and DuraCreteblended cement under both unconfined compressive (UC) and consolidated isotropic undrained (CIU) conditions were investigated in this study. The experimental results proved that fly ash and DuraCrete can be used as partial replacements of cement to achieve more remarkable improvement results than just cement alone in stabilising soft soils. DuraCrete is more effective compared to fly ash because the addition of DuraCrete can reduce the amount of cement needed for the stabilisation while also improving the strength of stabilised specimens. This project seeks to investigate a) the mechanical behaviour of South East Queensland soft soil stabilised by cement with different cement content; b) the effect of the presence of silt particles on the mechanical behaviour of soft soils, such as evaluating the behaviour of silty soils within the critical-state framework; c) the effect of the presence of silt particles on the mechanical and microstructural of soft soils after stabilised by cement; and d) the use of fly ash and DuraCrete as partial replacements of cement in soft soil stabilisation. A series of laboratory tests consisting of consolidated isotropic undrained (CIU) triaxial tests, unconfined compressive strength (UCS) tests, and scanning electron microscope (SEM) tests were conducted in this study to achieve these objectives. South East Queensland soft soil was collected and stabilised by cement with varying initial soil water content and cement content. The mechanical and microstructural behaviour of natural and cement-stabilised South East Queensland soft soil was investigated. Some empirical equations were derived to estimate the strength of South East Queensland soft soil specimens with different cement content. The microstructure of cement-stabilised soil specimens was also analysed and interpreted. A series of triaxial compressive tests were conducted in this study on five types of soft soils with varying clay and silt contents, and therefore the effect of silt contents on the strength and critical state behaviours of soft soils were investigated. The empirical equations were proposed to evaluate the effect of silt content on the stress paths of reconstituted soft soils under consolidated isotropic undrained triaxial tests and the critical state parameters. Based on the observations from the CIU triaxial compression tests, it can be concluded that 1. For silty soils which have a plasticity index above 29%, even the soils are classified as silt by Atterberg limit testing results, but the soils show clay-like behaviour in the critical state framework, evidenced by the corresponding normally consolidated line (NCL) and critical state line (CSL) are parallel. 2. For silty soils, which have a plasticity index between 19% and 29%, the soils show a transitional behaviour between the clay-like and sand-like behaviour, as the corresponding normally consolidated line (NCL) and critical state line (CSL) are becoming non-parallel. 3. For silty soils, which have a plasticity index lower than 19%, it shows typical sand-like behaviour. These types of soft soils were then stabilised by cement with varying cement content. A further series of unconfined compression tests were conducted for each group of cement-stabilised soil specimens. As the silt content might exhibit a different influence on the strength of cement-stabilised samples, a varying dosage of cement content was considered in this study. The experimental results indicate that silt content plays a different role in soil stabilisation under different cement contents. The effect of cement content and silt content on the microstructure development of stabilised soils were also analysed by utilising the Scanning Electron Microscope (SEM) images. With the increase of cement dosage, the number of cementitious products, such as reticulated CSH and needle-shaped ettringite, was notably increased, resulting in a denser structure. This can be attributed to the hydration of cement and the pozzolanic reactions. As for the effect of silt content, since particle size plays a significant role in microstructure development, both cement and silt contents can dramatically affect the pore size distribution. When the cement content is lower than 10%, clay platelets can fill the pore spaces and the cementitious products can enhance the inter-cluster bond strength by aggregating clay and silt platelets together to form larger and denser aggregates responsible for the strength improvement. When the cement content is between 10% and 20%, the stabilised soil strengths increase with the increase of silt content and then decrease when silt contents are higher than 50%. This is because the strength gained from cementitious product enhancement was partially countered by the increment of pore size caused by the excessive cement and silt contents. When the cement content is higher than 20%, the strength shows a negative correlation with silt content, which can be attributed to the incomplete reaction of cement due to the reduction of clay content. Regarding the partial replacement of cement by adopting fly ash and DuraCrete, the UCS and CIU testing results show that both fly ash and DuraCrete are very effective as partial replacements of cement to reduce the cement content and CO2 emission. Fly ash can the provide the highest reduction in the cement replacement content, and it can also provide the highest reduction in CO2 emission. However, at the same mixture content (e.g., 25%), the UCS of the specimens stabilised by fly ash-blended cement is lower than that stabilised by cement only. Thus, more material is needed when using fly ash to partially replace cement to maintain the same UCS. Even though, the CO2 footprint can still be reduced because the CO2 emission rate of fly ash is much lesser than that of pure cement. Therefore, fly ash is effective as a partial replacement of cement to reduce the use of cement and CO2 emission. Compared to fly ash, DuraCrete is more effective as a partial replacement of cement in some circumstances. For example, the total mixture content is reduced to achieve a target strength of 500 kPa when using DuraCrete-blended cement instead of pure cement only. The reduction in total mixture content is an essential advantage by using DuraCrete compared to using fly ash. Comparing the proportional quantities of fly ash and DuraCrete required, the quantity of fly ash required is between 6.1 times and 9.7 times the proportional quantity of DuraCrete required. Even though the use of DuraCrete can reduce the amount of cement used and reduce the total mixture content, it cannot provide as much reduction in cement as fly ash does. This is because there is a ‘saturation point’ with the DuraCrete replacement ratio. If this saturation point is exceeded, DuraCrete will not be as effective anymore, being mainly a magnesiumbased additive. Therefore, when the maximum reduction in cement is the only factor under consideration, fly ash is more suitable than DuraCrete, as it facilitates a greater reduction in cement. However, suppose both reduction in cement and the total mixture content are considered. In that case, DuraCrete might be more appropriate, as it not only reduces the use of cement but also reduces the total mixture content required. Most importantly, unlike cement and fly ash, the production of DuraCrete is not carbon-intensive. The production of DuraCrete does not produce carbon emission as it does not require a furnace, nor is it a by-product of a carbon emitting process. These critical outcomes can help engineers reliably customise the soil stabilisation design to achieve optimal strength, environmental friendliness, and cost-saving. As such, engineers can have more design options to meet the strength requirement while having the opportunity to minimise the negative impact on the environment by reducing the use of cement. They can also achieve a balance between the reduction in cement and the budget, hence the important contribution of this study.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Eng & Built Env<br>Science, Environment, Engineering and Technology<br>Full Text

.<br>Introduction: The present study aimed to take advantage of residues such as the Persea Americana (avocado) peel to obtain flour used in the preparation of a food of high consumption in the Peruvian population, noodles. Objectives: To evaluate the nutritional composition of the production of noodles by partially substituting wheat flour for Persea Americana shell flour. Methods: Laboratory study carried out in the laboratories of the Peruvian University of Applied Sciences (UPC) and Certificaciones Del Perú CERPER. Results: Titratable acidity (1.0), ash (2.85), fiber (50.08) and moisture (6.89) were determined in avocado peel flour. Wheat flour was substituted for avocado peel flour at 0, 10, 15 and 20%, being F0, F1, F2 and F3 respectively. In F0, ash (0.56), moisture (32.7), proteins (10.13), fats (3), fiber (0.85) and carbohydrates (53.49) were determined. In F1 ashes (0.76), moisture (35.60), proteins (9.68), fats (3.20), fiber (3.44) and carbohydrates (50.76). F2 ashes (0.85), moisture (37.25), proteins (9.23), fats (3.11), fiber (5.18) and carbohydrates (49.56). Finally, F3 ashes (0.94), moisture (41.21), proteins (7.71), fats (2.66), fiber (9.88) and carbohydrates (47.48).  Conclusions: Flour and noodles met the characteristics stipulated by Peruvian Technical Standards (NTP 205.053:1987 y NTS 071-2008 DIGESA - MINSA) and CODEX (Codex Stan 152-1985). The fiber in the final product was highlighted and the microbiological parameters requested by DIGESA - MINSA were met.<br>Introducción: El presente estudio tuvo como finalidad aprovechar residuos como la cáscara de Persea Americana (palta) para la obtención de harina usada en la elaboración de un alimento de alto consumo en la población peruana, fideos. Objetivo general: Evaluar la composición nutricional de la elaboración de fideos mediante sustitución parcial de harina de trigo por harina de cáscara de Persea Americana. Métodos: Estudio de laboratorio realizado en los laboratorios de la Universidad Peruana de Ciencias Aplicadas (UPC) y Certificaciones Del Perú CERPER. Resultados: En la harina de cáscara de palta se determinó acidez titulable (1.0), cenizas (2.85), fibra (50.08) y humedad (6.89). Se realizaron sustituciones de harina de trigo por harina de cáscara de palta al 0, 10, 15 y 20%, siendo F0, F1, F2 y F3 respectivamente. En F0 se determinó cenizas (0.56), humedad (32.7), proteínas (10.13), grasas (3), fibra (0.85) y carbohidratos (53.49). En F1 cenizas (0.76), humedad (35.60), proteínas (9.68), grasas (3.20), fibra (3.44) y carbohidratos (50.76). F2 cenizas (0.85), humedad (37.25), proteínas (9.23), grasas (3.11), fibra (5.18) y carbohidratos (49.56). Finalmente, F3 cenizas (0.94), humedad (41.21), proteínas (7.71), grasas (2.66), fibra (9.88) y carbohidratos (47.48). Conclusiones: Harina y fideos cumplieron con características estipuladas por Normas Técnicas Peruanas (NTP 205.053:1987 y NTS 071-2008 DIGESA - MINSA) y las normas CODEX (Codex Stan 152-1985). Se destacó la fibra en el producto final y se cumplió con los parámetros microbiológicos solicitados por DIGESA - MINSA.<br>Tesis

The issue of lead exposure through drinking water was re-examined in light of modern public health goals, recent high-profile cases of elevated lead in water, and emerging concerns regarding the efficacy of legally mandated remedial strategies. A critical literature review revealed that serious lead-in-water hazards are present at many US schools and homes, and that the threat to individuals is not eliminated by existing regulations. Health studies have provided strong links between lead in water and lead in blood of exposed populations, even at relatively low levels of exposure compared to reported lead occurrence in US tap water samples. As efforts shift from addressing pervasive lead sources that once elevated the blood lead of large percentages of the population, to more isolated individual cases requiring exceptional attention, the importance of carefully considering lead in water as a potential source for elevated blood lead increases. Consistent with decades of prior research linking elevated water lead to elevated blood lead (EBL), lead-contaminated water in the high-profile case of Washington DC markedly increased the incidence of EBL for very young children. Specifically, incidence of EBL for children aged ≤ 1.3 years increased more than 4 times during 2001-2003 when lead in water was high, compared to 2000 when lead in water was low. The incidence of EBL for children aged ≤ 1.3 years was highly correlated (R² = 0.81) to 90th percentile lead-in-water levels from 2000-2007, and the risk of exposure to high water lead levels varied markedly in different neighborhoods of the city. Analysis conducted herein focused on identifying "worst-case" neighborhoods and populations. Specifically, this was the first study of the Washington DC case to focus on infants who are most vulnerable to harm from lead in water, and to perform smaller area analysis at the neighborhood (i.e., zip code) level in order to capture pockets of high risk among local communities. Prior biokinetic modeling efforts, examining the potential adverse impacts of lead-in-water exposure, were re-examined to explicitly consider new public health goals. This included impacts on the most sensitive population groups (e.g., young children and particularly formula-fed infants), the potential variability in blood lead levels (BLLs) amongst exposed individuals within those groups (e.g., most sensitive children at the upper tail of the BLL distribution), more conservative BLL thresholds reflecting low-level adverse effects (e.g., 5, 2 and 1 µg/dL versus 10 µg/dL), and the possibility of acute health impacts. This re-evaluation creates a paradigm shift, in that levels of lead in water that were previously considered inconsequential are demonstrated to be of concern in specific circumstances. The replacement of lead service lines in front of consumers' homes is a costly, federally mandated remedial action if a water utility exceeds the US EPA lead action level. Because utilities do not own the entire lead service line, they often only replace the portion of the service line up to the property line, typically with copper pipe. Experiences in Washington DC, as revealed by Freedom of Information Act requests, indicated that partial pipe replacements were not decreasing lead in water, and were actually associated with relatively high incidence of childhood lead poisoning. This prompted the first comprehensive investigation of potential long-term problems arising from galvanic corrosion between the remaining lead pipe and the newly installed copper pipe. Bench-scale experiments demonstrated that galvanic connections between lead pipe (new or aged) and copper pipe increased lead release into the water by 1.1-16 times, when compared to a full length of lead pipe alone. The small area of lead pipe adjacent to the copper joint (<0.5 ft) was gravely affected by galvanic corrosion, and accumulated a thick lead-rust layer (1 inch wide) that constituted a reservoir for semi-random particulate lead detachment into the water. The work on simulated partial pipe replacements revealed that under worst-case scenarios of highly contaminated water samples, most of the lead was not quantified if water samples were not mixed thoroughly after standard preservation (i.e., after addition of 0.15% v/v HNO₃), or if water samples were transferred from one bottle to another prior to preservation. While there is no reason to believe that sample handling and pre-treatment dramatically skew regulatory compliance with the US EPA lead action level, slight variations from one approved protocol to another may cause lead-in-water health risks to be dramatically underestimated. This is of special concern in unusual situations of "worst-case" individual exposures to highly contaminated water, associated with childhood lead poisoning. This work provides the water industry and health agencies with important new insights and perspectives on an old problem. Results can improve strategies to detect and mitigate lead-in-water hazards for individuals or populations, and inform future revisions to the US EPA Lead and Copper Rule.<br>Ph. D.