Combining data mining and evolutionary computation for multi-criteria optimization of earthworks

Earthworks tasks aim at levelling the ground surface at a target construction area and precede any kind of structural construction (e.g., road and railway construction). It is comprised of sequential tasks, such as excavation, transportation, spreading and compaction, and it is strongly based on heavy mechanical equipment and repetitive processes. Under this context, it is essential to optimize the usage of all available resources under two key criteria: the costs and duration of earthwork projects. In this paper, we present an integrated system that uses two artificial intelligence based techniques: data mining and evolutionary multi-objective optimization. The former is used to build data-driven models capable of providing realistic estimates of resource productivity, while the latter is used to optimize resource allocation considering the two main earthwork objectives (duration and cost). Experiments held using real-world data, from a construction site, have shown that the proposed system is competitive when compared with current manual earthwork design.

Modern optimization in earthwork construction

Earthworks tasks are often regarded in transportation projects as some of the most demanding processes. In fact, sequential tasks such as excavation, transportation, spreading and compaction are strongly based on heavy mechanical equipment and repetitive processes, thus becoming as economically demanding as they are time-consuming. Moreover, actual construction requirements originate higher demands for productivity and safety in earthwork constructions. Given the percentual weight of costs and duration of earthworks in infrastructure construction, the optimal usage of every resource in these tasks is paramount. Considering the characteristics of an earthwork construction, it can be looked at as a production line based on resources (mechanical equipment) and dependency relations between sequential tasks, hence being susceptible to optimization. Up to the present, the steady development of Information Technology areas, such as databases, artificial intelligence and operations research, has resulted in the emergence of several technologies with potential application bearing that purpose in mind. Among these, modern optimization methods (also known as metaheuristics), such as evolutionary computation, have the potential to find high quality optimal solutions with a reasonable use of computational resources. In this context, this work describes an optimization algorithm for earthworks equipment allocation based on a modern optimization approach, which takes advantage of the concept that an earthwork construction can be regarded as a production line.

Development of an intelligent earthwork optimization system

Tese de Doutoramento em Engenharia Civil.

Hankinnan tietojärjestelmäintegraatiot raskaassa konepajateollisuudessa

Tässä diplomityössä tarkastellaan sähköisen liiketoiminnan mukanaan tuomia mahdollisuuksia yrityksen hankintatoimen prosessien tehostamiseksi. Työ keskittyy erityisesti raskaassa konepajateollisuudessa toimivan yrityksen, Metso Paperin, hankinnan tietojärjestelmien integroimiseen. Pääasiallinen tutkimusmenetelmä on kirjallisuustutkimus, jota lisäksi täydennetään empiirisesti tutkittujen case-tapauksien avulla, joissa tarkastellaan sähköisen hankintatoimen käytännön toteutusta Metso Paperin ja sen alihankkijan, Toijala Worksin välillä. Diplomityön tavoitteena on esittää yrityksen hankintaverkoston ja siihen kuuluvien alihankkijoiden toiminnan uudelleen organisoiminen ja hallitseminen, minkä lisäksi työssä käsitellään myös hankintastrategian merkitystä yrityksen liiketoiminnan kannalta. Työn tietotekninen osuus keskittyy sähköisen liiketoiminnan edellyttämän tietojärjestelmän suunnittelemiseen, mutta ei sen käytännön toteuttamiseen. Työn tärkein tulos on sähköisenliiketoiminnan aloittamisen mahdollistava kaksivaiheinen tiedonsiirtomalli, jonka ensimmäinen vaihe perustuu jo olemassa olevien tietojärjestelmien, eli Extranet- ja Notes -työpöytien, hyödyntämiseen uudella, aiempaa tehokkaammalla tavalla. Mallin toinen vaihe jakautuu yrityksen sisäisen ja ulkoisen tiedonsiirtoon. Toisen vaiheen keskeinen tulos on ratkaisuehdotus sisäisten ja ulkoisten tietojärjestelmien toimintojen ja tietojen saumattomaksi integroimiseksi toisiinsa, eli tutkimuskohteena olevan yrityksen hankintaverkostoon ja sen erityispiirteisiin sopiva sähköisen kaupankäynnin sovellutus.

Teleskooppimaston sähkökäyttöjen suunnittelu ja kehittäminen

Työssä kehitettiin kahdesta sähkökäytöstä ja erillisistä vinsseistä koostuva teleskooppimaston putkien nostamiseen ja laskemiseen tarkoitettu vinssijärjestelmä. Järjestelmällä voidaan korvata mekaanisesti monimutkainen ja painava yhdellä sähkökäytöllä toteutettu vinssijärjestelmä. Järjestelmän sähkökäytöt käyttävät vinssien välityksellä mastoon kiinnitettyjä hihnoja. Toinen sähkökäytöistä on säätämätön ja toinen vääntömomenttisäädetty. Säätämätön sähkökäyttö määrää maston nosto- ja laskunopeuden. Vääntömomenttisäädetty sähkökäyttö pitää mastoa käyttävät hihnat sopivalla kireydellä, jolloinmaston nostaminen ja laskeminen voivat tapahtua hallitusti.

Effects of silicon content and cooling rate on mechanical properties of heavy section ductile cast iron

The effects of Si and cooling rate are investigated for their effect on the mechanical properties and microstructure. Three alloys were chosen with varying C and Si contents and an attempt to keep the remainder of the elements present constant. Within each heat, three test blocks were poured. Two blocks had chills – one with a fluid flowing through it to cool it (active chill) and one without the fluid (passive) – and the third block did not have a chill. Cooling curves were gathered and analyzed. The mechanical properties of the castings were correlated to the microstructure, cooling rate and Si content of each block. It was found that an increase in Si content increased the yield stress, tensile strength and hardness but decreased the impact toughness, elongation and Young’s modulus. The fast cooling rates produced by the chills caused a high nodule count in the castings along with a fine ferrite grain size and a high degree of nodularity. The fine microstructures, in turn, increased the strength and ductile to brittle transition temperature (DBTT) of the castings. The fast cooling rate was not adequate to overcome the dramatic increase in DBTT that is caused by the addition of Si.

Mechanical effects on the skeleton: Are there clinical implications?

The basic morphology of the skeleton is determined genetically, but its final mass and architecture are modulated by adaptive mechanisms sensitive to mechanical factors. When subjected to loading, the ability of bones to resist fracture depends on their mass, material properties, geometry and tissue quality. The contribution of altered bone geometry to fracture risk is unappreciated by clinical assessment using absorptiometry because it fails to distinguish geometry and density. For example, for the same bone area and density, small increases in the diaphyseal radius effect a disproportionate influence on torsional strength of bone. Mechanical factors are clinically relevant because of their ability to influence growth, modeling and remodeling activities that can maximize, or maintain, the determinants of fracture resistance. Mechanical loads, greater than those habitually encountered by the skeleton, effect adaptations in cortical and cancellous bone, reduce the rate of bone turnover, and activate new bone formation on cortical and trabecular surfaces. In doing so, they increase bone strength by beneficial adaptations in the geometric dimensions and material properties of the tissue. There is no direct evidence to demonstrate anti-fracture efficacy for mechanical loading, but the geometric alterations engendered undoubtedly increase the structural properties of bone as an organ, increasing the resistance to fracture. Like all interventions, issues of safety also arise. Physical activities involving high strain rates, heavy lifting or impact loading may be detrimental to the joints, leading to osteoarthritis; may stimulate fatigue damage leading with some to stress fractures; or may interact pharmaceutical interventions to increase the rate of microdamage within cortical or trabecular bone.

Mechanical properties of rat cardiac skinned fibers are altered by chronic growth hormone hypersecretion.

Chronic growth hormone (GH) hypersecretion in rats leads to increased isometric force without affecting the unloaded shortening velocity of isolated cardiac papillary muscles, despite a marked isomyosin shift toward V3. To determine if alterations occurred at the level of the contractile proteins in rats bearing a GH-secreting tumor (GH rats), we examined the mechanical properties of skinned fibers to eliminate the early steps of the excitation-contraction coupling mechanism. We found that maximal active tension and stiffness at saturating calcium concentrations (pCa 4.5) were markedly higher in GH rats than in control rats (tension, 52.9 +/- 5.2 versus 38.1 +/- 4.6 mN.mm-2, p < 0.05; stiffness, 1,105 +/- 120 versus 685 +/- 88 mN.mm-2.microns-1, p < 0.01), whereas values at low calcium concentrations (pCa 9) were unchanged. In addition, the calcium sensitivity of the contractile proteins was slightly but significantly higher in GH rats than in control rats (delta pCa 0.04, p < 0.001). The crossbridge cycling rate, reflected by the response to quick length changes, was lower in GH rats than in control rats (62.0 +/- 2.6 versus 77.4 +/- 6.6 sec-1, p < 0.05), in good agreement with a decrease in the proportion of alpha-myosin heavy chains in the corresponding papillary muscles (45.5 +/- 2.0% versus 94.6 +/- 2.4%, p < 0.001). The changes in myosin heavy chain protein phenotype were paralleled by similar changes of the corresponding mRNAs, indicating that the latter occurred mainly at a pretranslational level. These results demonstrate that during chronic GH hypersecretion in rats, alterations at the myofibrillar level contribute to the increase in myocardial contractility observed in intact muscle.

Performance of a reciprocal shaker in mechanical dispersion of soil samples for particle-size analysis

The dispersion of the samples in soil particle-size analysis is a fundamental step, which is commonly achieved with a combination of chemical agents and mechanical agitation. The purpose of this study was to evaluate the efficiency of a low-speed reciprocal shaker for the mechanical dispersion of soil samples of different textural classes. The particle size of 61 soil samples was analyzed in four replications, using the pipette method to determine the clay fraction and sieving to determine coarse, fine and total sand fractions. The silt content was obtained by difference. To evaluate the performance, the results of the reciprocal shaker (RSh) were compared with data of the same soil samples available in reports of the Proficiency testing for Soil Analysis Laboratories of the Agronomic Institute of Campinas (Prolab/IAC). The accuracy was analyzed based on the maximum and minimum values defining the confidence intervals for the particle-size fractions of each soil sample. Graphical indicators were also used for data comparison, based on dispersion and linear adjustment. The descriptive statistics indicated predominantly low variability in more than 90 % of the results for sand, medium-textured and clay samples, and for 68 % of the results for heavy clay samples, indicating satisfactory repeatability of measurements with the RSh. Medium variability was frequently associated with silt, followed by the fine sand fraction. The sensitivity analyses indicated an accuracy of 100 % for the three main separates (total sand, silt and clay), in all 52 samples of the textural classes heavy clay, clay and medium. For the nine sand soil samples, the average accuracy was 85.2 %; highest deviations were observed for the silt fraction. In relation to the linear adjustments, the correlation coefficients of 0.93 (silt) or > 0.93 (total sand and clay), as well as the differences between the angular coefficients and the unit < 0.16, indicated a high correlation between the reference data (Prolab/IAC) and results obtained with the RSh. In conclusion, the mechanical dispersion by the reciprocal shaker of soil samples of different textural classes was satisfactory. The results allowed recommending the use of the equipment at low agitation for particle size- analysis. The advantages of this Brazilian apparatus are its low cost, the possibility to simultaneously analyze a great number of samples using ordinary, easily replaceable glass or plastic bottles.

Studies on grain refinement and alloying additions on the microstructure and mechanical properties of Mg-8Zn-4Al alloy

MAGNESIUM ALLOYS have strong potential for weight reduction in a wide range of technical applications because of their low density compared to other structural metallic materials. Therefore, an extensive growth of magnesium alloys usage in the automobile sector is expected in the coming years to enhance the fuel efficiency through mass reduction. The drawback associated with the use of commercially cheaper Mg-Al based alloys, such as AZ91, AM60 and AM50 are their inferior creep properties above 100ºC due to the presence of discontinuous Mg17A112 phases at the grain boundaries. Although rare earth-based magnesium alloys show better mechanical properties, it is not economically viable to use these alloys in auto industries. Recently, many new Mg-Al based alloy systems have been developed for high temperature applications, which do not contain the Mg17Al12 phase. It has been proved that the addition of a high percentage of zinc (which depends upon the percentage of Al) to binary Mg-Al alloys also ensures the complete removal of the Mg17Al12 phase and hence exhibits superior high temperature properties.ZA84 alloy is one such system, which has 8%Zn in it (Mg-8Zn-4Al-0.2Mn, all are in wt %) and shows superior creep resistance compared to AZ and AM series alloys. These alloys are mostly used in die casting industries. However, there are certain large and heavy components, made up of this alloy by sand castings that show lower mechanical properties because of their coarse microstructure. Moreover, further improvement in their high temperature behaviour through microstructural modification is also an essential task to make this alloy suitable for the replacement of high strength aluminium alloys used in automobile industry. Grain refinement is an effective way to improve the tensile behaviour of engineering alloys. In fact, grain refinement of Mg-Al based alloys is well documented in literature. However, there is no grain refiner commercially available in the market for Mg-Al alloys. It is also reported in the literature that the microstructure of AZ91 alloy is modified through the minor elemental additions such as Sb, Si, Sr, Ca, etc., which enhance its high temperature properties because of the formation of new stable intermetallics. The same strategy can be used with the ZA84 alloy system to improve its high temperature properties further without sacrificing the other properties. The primary objective of the present research work, “Studies on grain refinement and alloying additions on the microstructure and mechanical properties of Mg-8Zn-4Al alloy” is twofold: 1. To investigate the role of individual and combined additions of Sb and Ca on the microstructure and mechanical properties of ZA84 alloy. 2. To synthesis a novel Mg-1wt%Al4C3 master alloy for grain refinement of ZA84 alloy and investigate its effects on mechanical properties.

Tailoring Magnetic Properties of Co-Fe Thin Films by Topographical Modifications Using Thermal Annealing and Swift Heavy Ion Irradiation and Fabrication of Magnetoelectric Multilayers for Device Applications

Magnetism and magnetic materials have been playing a lead role in improving the quality of life. They are increasingly being used in a wide variety of applications ranging from compasses to modern technological devices. Metallic glasses occupy an important position among magnetic materials. They assume importance both from a scientific and an application point of view since they represent an amorphous form of condensed matter with significant deviation from thermodynamic equilibrium. Metallic glasses having good soft magnetic properties are widely used in tape recorder heads, cores of high-power transformers and metallic shields. Superconducting metallic glasses are being used to produce high magnetic fields and magnetic levitation effect. Upon heat treatment, they undergo structural relaxation leading to subtle rearrangements of constituent atoms. This leads to densification of amorphous phase and subsequent nanocrystallisation. The short-range structural relaxation phenomenon gives rise to significant variations in physical, mechanical and magnetic properties. Magnetic amorphous alloys of Co-Fe exhibit excellent soft magnetic properties which make them promising candidates for applications as transformer cores, sensors, and actuators. With the advent of microminiaturization and nanotechnology, thin film forms of these alloys are sought after for soft under layers for perpendicular recording media. The thin film forms of these alloys can also be used for fabrication of magnetic micro electro mechanical systems (magnetic MEMS). In bulk, they are drawn in the form of ribbons, often by melt spinning. The main constituents of these alloys are Co, Fe, Ni, Si, Mo and B. Mo acts as the grain growth inhibitor and Si and B facilitate the amorphous nature in the alloy structure. The ferromagnetic phases such as Co-Fe and Fe-Ni in the alloy composition determine the soft magnetic properties. The grain correlation length, a measure of the grain size, often determines the soft magnetic properties of these alloys. Amorphous alloys could be restructured in to their nanocrystalline counterparts by different techniques. The structure of nanocrystalline material consists of nanosized ferromagnetic crystallites embedded in an amorphous matrix. When the amorphous phase is ferromagnetic, they facilitate exchange coupling between nanocrystallites. This exchange coupling results in the vanishing of magnetocrystalline anisotropy which improves the soft magnetic properties. From a fundamental perspective, exchange correlation length and grain size are the deciding factors that determine the magnetic properties of these nanocrystalline materials. In thin films, surfaces and interfaces predominantly decides the bulk property and hence tailoring the surface roughness and morphology of the film could result in modified magnetic properties. Surface modifications can be achieved by thermal annealing at various temperatures. Ion irradiation is an alternative tool to modify the surface/structural properties. The surface evolution of a thin film under swift heavy ion (SHI) irradiation is an outcome of different competing mechanism. It could be sputtering induced by SHI followed by surface roughening process and the material transport induced smoothening process. The impingement of ions with different fluence on the alloy is bound to produce systematic microstructural changes and this could effectively be used for tailoring magnetic parameters namely coercivity, saturation magnetization, magnetic permeability and remanence of these materials. Swift heavy ion irradiation is a novel and an ingenious tool for surface modification which eventually will lead to changes in the bulk as well as surface magnetic property. SHI has been widely used as a method for the creation of latent tracks in thin films. The bombardment of SHI modifies the surfaces or interfaces or creates defects, which induces strain in the film. These changes will have profound influence on the magnetic anisotropy and the magnetisation of the specimen. Thus inducing structural and morphological changes by thermal annealing and swift heavy ion irradiation, which in turn induce changes in the magnetic properties of these alloys, is one of the motivation of this study. Multiferroic and magneto-electrics is a class of functional materials with wide application potential and are of great interest to material scientists and engineers. Magnetoelectric materials combine both magnetic as well as ferroelectric properties in a single specimen. The dielectric properties of such materials can be controlled by the application of an external magnetic field and the magnetic properties by an electric field. Composites with magnetic and piezo/ferroelectric individual phases are found to have strong magnetoelectric (ME) response at room temperature and hence are preferred to single phasic multiferroic materials. Currently research in this class of materials is towards optimization of the ME coupling by tailoring the piezoelectric and magnetostrictive properties of the two individual components of ME composites. The magnetoelectric coupling constant (MECC) (_ ME) is the parameter that decides the extent of interdependence of magnetic and electric response of the composite structure. Extensive investigates have been carried out in bulk composites possessing on giant ME coupling. These materials are fabricated by either gluing the individual components to each other or mixing the magnetic material to a piezoelectric matrix. The most extensively investigated material combinations are Lead Zirconate Titanate (PZT) or Lead Magnesium Niobate-Lead Titanate (PMNPT) as the piezoelectric, and Terfenol-D as the magnetostrictive phase and the coupling is measured in different configurations like transverse, longitudinal and inplane longitudinal. Fabrication of a lead free multiferroic composite with a strong ME response is the need of the hour from a device application point of view. The multilayer structure is expected to be far superior to bulk composites in terms of ME coupling since the piezoelectric (PE) layer can easily be poled electrically to enhance the piezoelectricity and hence the ME effect. The giant magnetostriction reported in the Co-Fe thin films makes it an ideal candidate for the ferromagnetic component and BaTiO3 which is a well known ferroelectric material with improved piezoelectric properties as the ferroelectric component. The multilayer structure of BaTiO3- CoFe- BaTiO3 is an ideal system to understand the underlying fundamental physics behind the ME coupling mechanism. Giant magnetoelectric coupling coefficient is anticipated for these multilayer structures of BaTiO3-CoFe-BaTiO3. This makes it an ideal candidate for cantilever applications in magnetic MEMS/NEMS devices. SrTiO3 is an incipient ferroelectric material which is paraelectric up to 0K in its pure unstressed form. Recently few studies showed that ferroelectricity can be induced by application of stress or by chemical / isotopic substitution. The search for room temperature magnetoelectric coupling in SrTiO3-CoFe-SrTiO3 multilayer structures is of fundamental interest. Yet another motivation of the present work is to fabricate multilayer structures consisting of CoFe/ BaTiO3 and CoFe/ SrTiO3 for possible giant ME coupling coefficient (MECC) values. These are lead free and hence promising candidates for MEMS applications. The elucidation of mechanism for the giant MECC also will be the part of the objective of this investigation.

Mechanical analysis of infant carrying in hominoids

In all higher nonhuman primates, species survival depends upon safe carrying of infants clinging to body hair of adults. In this work, measurements of mechanical properties of ape hair (gibbon, orangutan, and gorilla) are presented, focusing on constraints for safe infant carrying. Results of hair tensile properties are shown to be species-dependent. Analysis of the mechanics of the mounting position, typical of heavier infant carrying among African apes, shows that both clinging and friction are necessary to carry heavy infants. As a consequence, a required relationship between infant weight, hair-hair friction coefficient, and body angle exists. The hair-hair friction coefficient is measured using natural ape skin samples, and dependence on load and humidity is analyzed. Numerical evaluation of the equilibrium constraint is in agreement with the knuckle-walking quadruped position of African apes. Bipedality is clearly incompatible with the usual clinging and mounting pattern of infant carrying, requiring a revision of models of hominization in relation to the divergence between apes and hominins. These results suggest that safe carrying of heavy infants justify the emergence of biped form of locomotion. Ways to test this possibility are foreseen here.

Determination of the oxygen and nitrogen interstitial diffusion coeficient in niobium by mechanical spectroscopy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of heavy interstitials on anelastic properties of Nb-1.0 wt% Zr alloys

The mechanical properties of metals with bcc structure, such as niobium and its alloys, have changed significantly with the introduction of heavy interstitial elements. These interstitial elements (nitrogen, for example), present in the alloy, occupy octahedral sites and constitute an elastic dipole of tetragonal symmetry and might produce anelastic relaxation. This article presents the effect of nitrogen on the anelastic properties of Nb-1.0 wt% Zr alloys, measured by means of mechanical spectroscopy using a torsion pendulum. The results showed complex anelastic relaxation structures, which were resolved into their constituent peaks, representing each relaxation process. These processes are due to stress-induced ordering of the interstitial elements around the niobium and zirconium of the alloy.

Performance of a reciprocal shaker in mechanical dispersion of soil samples for particle-size analysis

A dispersão da amostra de solo é uma etapa fundamental da análise granulométrica, sendo realizada mediante o uso de dispersantes químicos e agitação mecânica. O objetivo deste trabalho foi avaliar a eficiência de mesa agitadora reciprocante de baixa rotação na dispersão mecânica de amostras de solos de diferentes classes texturais. Foram realizadas análises granulométricas em 61 amostras com quatro repetições, empregando o método da pipeta para determinação da fração argila e tamisagem para determinação das frações areia grossa, areia fina e areia total, sendo o silte determinado por diferença. Na avaliação de desempenho, os resultados obtidos com uso da mesa agitadora reciprocante (MAR) foram comparados com dados disponíveis para as mesmas amostras oriundos de relatórios do Ensaio de Proficiência IAC para Laboratórios de Análises de Solos - Prolab/IAC. Análises de acurácia foram realizadas com base nos valores dos intervalos de confiança definidos para cada fração granulométrica componente de cada amostra ensaiada. Indicadores gráficos também foram utilizados na comparação de dados, por meio de dispersão e ajuste linear. A estatística descritiva indicou preponderância de baixa variabilidade em mais de 90 % dos resultados obtidos para as amostras de texturas arenosa, média e argilosa e em 68 % dos obtidos para as amostras de textura muito argilosa, indicando boa repetibilidade dos resultados obtidos com a MAR. Média variabilidade foi mais frequentemente associada à fração silte, seguida da fração areia fina. Os resultados das análises de sensibilidade indicam acurácia de 100 % nas três frações granulométricas - areia total, silte e argila - para todas as amostras analisadas pertencentes às classes texturais muito argilosa, argilosa e média. Para as nove amostras de textura arenosa, a acurácia média foi de 85,2 %, e os maiores desvios ocorreram em relação à fração silte. Nas aproximações lineares, coeficientes de correlação igual (silte) ou superiores (areia total e argila) a 0,93, bem como diferenças menores do que 0,16 entre os coeficientes angulares das retas e o valor unitário, indicam alta correlação entre os resultados de referência (Prolab/IAC) e os obtidos nos ensaios com a MAR. Conclui-se pelo desempenho satisfatório da mesa agitadora reciprocante de baixa rotação para dispersão mecânica de amostras de solo de diferentes classes texturais para fins de análise granulométrica, permitindo recomendar o uso alternativo do equipamento quando se emprega agitação lenta. As vantagens do uso do equipamento nacional incluem o baixo custo, a possibilidade de análise simultânea de grande número de amostras e o uso de frascos comuns, de vidro ou de plástico, baratos e de fácil reposição.