Obtenção de emulsões asfálticas convencionais e modificadas com argilas e nanoargilas

The increasing demand for asphalt leads to the development of techniques that can improve the quality of products and increase the useful working life of pavements. Consequently, there is a growing application of asphalt emulsions, which are produced from a mixture of petroleum asphalt cement (CAP) with an aqueous phase. The main advantage of asphalt emulsions is its cold application, reducing energy costs. Conventional emulsions are obtained using asphalt, water, solvent, and additives. The modified asphalt emulsion is developed by adding a modifying agent to conventional emulsions. These modifiers can be natural fibers, waste polymers, nanomaterials. In this work modified asphalt emulsion were obtained using organoclays. First, it was prepared a conventional asphalt emulsion with the following mass proportion: 50% of 50/70 penetration grade CAP, 0.6% of additives and 3% of emulsifier, 20% of solvent and 26.4% of water. It was used bentonite and vermiculite (1% and 4%) to obtain the modified asphalt emulsion. Bentonite and vermiculite were added in its raw state and as an organoclay form and as an organoclay-acid form, resulting in 26 experimental runs. The methodology described by Qian et al. (2011), with modifications, was used to obtain the organoclay and the organoclay-acid form. infrared spectroscopy (IR)) were used to characterize the clays and nanoclays. The emulsions were prepared in a colloidal mill, using 30 minutes and 1 hour as mixing time. After, the emulsions were characterized. The following tests were performed, in accordance with the Brazilian specifications (DNER- 369/97): sieve analysis, Saybolt Furol viscosity, pH determination, density, settlement and storage stability, residue by evaporation, and penetration of residue. Finally, it can be concluded that the use of nanoclays as asphalt modifiers represent a viable alternative to the road paving industry

Methanogenic potential and microbial community of anaerobic batch reactors at different ethylamine/sulfate ratios

Methylamine and sulfate are compounds commonly found in wastewaters. This study aimed to determine the methanogenic potential of anaerobic reactors containing these compounds and to correlate it with their microbial communities. Batch experiments were performed at different methylamine/sulfate ratios of 0.71, 1.26 and 2.18 (with respect to mass concentration). Control and experimental runs were inoculated with fragmented granular sludge. The maximum specific methane formation rates were approximately 2.3 mmol CH4 L-1 g TVS-1 day-1 for all conditions containing methylamine, regardless of sulfate addition. At the end of the experiment, total ammonium-N and methane formation were proportional to the initial concentrations of methylamine. In the presence of methylamine and sulfate, Firmicutes (46%), Deferribacteres (13%) and Proteobacteria (12%) were the predominant phyla of the Bacteria domain, while Spirochaetes (40%), Deferribacteres (17%) and Bacteroidetes (16%) predominated in the presence of methylamine only. There was no competition for methylamine between sulfate-reducing bacteria and methanogenic archaea.

Degradation of Acid Blue 40 dye solution and dye house wastewater from textile industry by photo-assisted electrochemical process

In this paper, electrochemical and photo-assisted electrochemical processes are used for color, total organic carbon (TOC) and chemical oxygen demand (COD) degradation of one of the most abundant and strongly colored industrial wastewaters, which results from the dyeing of fibers and fabrics in the textile industry. The experiments were carried out in an 18L pilot-scale tubular low reactor with 70% TiO2/30% RuO2 DSA. A synthetic acid blue 40 solution and real dye house wastewater, containing the same dye, were used for the experiments. By using current density of 80 mA cm(-2) electrochemical process has the capability to remove 80% of color, 46% of TOC and 69% of COD. When used the photochemical process with 4.6 mW cm(-2) of 254nm UV-C radiation to assist the electrolysis, has been obtained 90% of color, 64% of TOC and 60% of COD removal in 90 minutes of processing; furthermore, 70% of initial color was degraded within the first 15 minutes. Experimental runs using dye house wastewater resulted in 78% of color, 26% of TOC and 49% of COD in electrolysis at 80 mA cm(-2) and 90 min; additionally, when photo-assisted, electrolysis resulted in removals of 85% of color, 42% of TOC and 58% of COD. For the operational conditions used in this study, color, TOC and COD showed pseudo-first-order decaying profiles. Apparent rate constants for degradation of TOC and COD were improved by one order of magnitude when the photo-electrochemical process was used.

Structural behaviour of three-pile caps subjected to axial compressive loading

This work presents a comparative analysis about the behaviour of pile caps supported by 3 piles subjected to axial loading. Piles with 20 cm and 30 cm diameters were analysed. The main reinforcement was maintained in all the specimens, however, the arrangement of the secondary reinforcement varied. The main reinforcement consisted of steel bars connecting the piles. The secondary reinforcement was made up of: (a) bars going through the piles and through the projection of the column, (b) bars forming a network, and (c) vertical and horizontal stirrups. The main objective was the observation of the pile cap behaviour regarding the cracks and the modes of rupture. The real scale specimens were subjected to experimental tests until failure by rupture. Instruments were placed with the aim to obtain the displacement of the bases, the strains in the main and secondary reinforcement bars, in the compression struts, in the lower and upper nodal zones and in the sides of the caps. None of the caps reached failure by rupture with a load less than 1.12 times the theoretical load. The specimens ruptured due to the cracking of the compression strut and/or the yielding of the reinforcement bars in one direction.

Avaliação das condições de secagem no rendimento e na qualidade do óleo de linhaça (Linum usitatissimum L.)

De origem asiática, a semente de linhaça (Linum usitatissimum L.) pertence à família das Lináceas e é obtida a partir do linho. A semente da linhaça é ainda a maior fonte alimentar de lignanas, compostos fotoquímicos parecidos com o estrogênio, que podem desempenhar ação anticancerígena. Rica em fibras solúveis tem aproximadamente 40% do seu peso composto por óleos ricos em Ômega 3, entre os quais se destaca o α-linolênico. A secagem é a operação unitária segundo o qual ocorre eliminação da água por evaporação ou sublimação, presente em um material, mediante a aplicação de calor com condições controladas. Visando averiguar o comportamento das sementes de linhaça durante a operação de secagem, o presente trabalho teve como objetivo principal realizar o planejamento experimental e analisar estatísticamente os resultados empregados para quantificar a influência da temperatura do ar (T), tempo de secagem (t), velocidade do ar de fluidização (Uf) e carga de sólidos (Cs), sobre a razão de umidade (Xr), rendimento em óleo (Rend.) e os parâmetros oleoquimicos. A estimativa do ponto ótimo de operação foi determinada em função das variáveis de entrada aplicando o conceito de desejabilidade global. Dentre as condições estabelecidas neste trabalho, o valor ótimo da Função Desejabilidade é quando T é deslocada próximo ao nível alto (72 oC), t para o mínimo (3 h), Uf para o ponto próximo ao central (0,83 m/s) e a Cs para o nível alto (500g), obtendo-se assim: 0,126 para Xr; 36,92 % para Rend.; 4,51 mg KOH/g para IA; 22,52 meqO2/Kg IP e 0,31% para DC. Foram obtidas as isotermas de dessorção das sementes de linhaça nas temperaturas de 40, 60 e 80°C. Os dados experimentais foram avaliados usando seis modelos matemáticos. A entalpia e a entropia diferencial de dessorção foram estimadas por meio das relações de Clausius-Clapeyron e Gibbs-Helmholtz, respectivamente. Os modelos de GAB e Peleg ajustaram adequadamente os dados experimentais. A teoria da compensação entalpia-entropia foi aplicada com sucesso às isotermas de dessorção e indica que o mecanismo de dessorção de umidade das sementes de linhaça pode ser considerado como controlado pela entalpia. A secagem das sementes de linhaça previamente umidificadas foram avaliadas em um secador de leito fixo e fluidizado, as corridas experimentais foram realizadas nas temperaturas de 40, 60 e 80°C, dentre dos cinco modelos propostos, o modelo de Midilli et al, foi o melhor modelo que melhor ajustou aos dados experimentais. Foi observado que a difusividade efetiva para as sementes de linhaça aumentou com a elevação da temperatura do ar de secagem para a secagem em leito fixo e fluidizado. A dependência da difusividade em relação à temperatura foi descrita pela equação de Arrhenius, por meio da qual se estimou para ambos os processos de secagem.

Monitoramento da condição da ferramenta de dressagem usando sinais de vibração e modelos neurais

Pós-graduação em Engenharia Elétrica - FEB

Transient expression of rabies virus G-glycoprotein using BHK-21 cells cultured in suspension

Objective To assess the expression of rabies virus G-glycoprotein (RVGP) expression using Semliki Forest virus as a vector in combination with BHK-21 cells cultured in suspension. Results A multilevel factorial design was used to quantify effects of temperature (33–37 C), fresh medium addition after the viral adsorption step (100–200 % with respect to the initial cell suspension volume before infection) and harvest time (8–40 h) on RVGP production. Experimental runs were performed in 24-well cell culture plates at a multiplicity of infection (MOI) of 16. An additional experiment in spinner-flask was performed at MOI of 9, using the optimal conditions determined in cell culture plates. Values for temperature, fresh medium addition and harvest time of 33 C, 100 % and 16 h, respectively, ensured the optimal RVGP production in culture plates. The volumetric yield (239 ng ml-1 ) in these conditions was higher than that reported previously for adherent cell culture. In spinner-flasks, the volumetric yield was improved (559 ng ml-1 ). Conclusion These results establish the basis for designing bioprocess to produce RVGP.

Sviluppo di biosensori: modifiche di superfici elettrodiche e sistemi di immobilizzazione enzimatica

An amperometric glucose biosensor was developed using an anionic clay matrix (LDH) as enzyme support. The enzyme glucose oxidase (GOx) was immobilized on a layered double hydroxide Ni/Al-NO3 LDH during the electrosynthesis, which was followed by crosslinking with glutaraldehyde (GA) vapours or with GA and bovine serum albumin (GABSA) to avoid the enzyme release. The electrochemical reaction was carried out potentiostatically, at -0.9V vs. SCE, using a rotating disc Pt electrode to assure homogeneity of the electrodeposition suspension, containing GOx, Ni(NO3)2 and Al(NO3)3 in 0.3 M KNO3. The mechanism responsible of the LDH electrodeposition involves the precipitation of the LDH due to the increase of pH at the surface of the electrode, following the cathodic reduction of nitrates. The Pt surface modified with the Ni/Al-NO3 LDH shows a much reduced noise, giving rise to a better signal to noise ratio for the currents relative to H2O2 oxidation, and a linear range for H2O2 determination wider than the one observed for bare Pt electrodes. We pointed out the performances of the biosensor in terms of sensitivity to glucose, calculated from the slope of the linear part of the calibration curve for enzimatically produced H2O2; the sensitivity was dependent on parameters related to the electrodeposition in addition to working conditions. In order to optimise the glucose biosensor performances, with a reduced number of experimental runs, we applied an experimental design. A first screening was performed considering the following variables: deposition time (30 - 120 s), enzyme concentration (0.5 - 3.0 mg/mL), Ni/Al molar ratio (3:1 or 2:1) of the electrodeposition solution at a total metals concentration of 0.03 M and pH of the working buffer solution (5.5-7.0). On the basis of the results from this screening, a full factorial design was carried out, taking into account only enzyme concentration and Ni/Al molar ratio of the electrosynthesis solution. A full factorial design was performed to study linear interactions between factors and their quadratic effects and the optimal setup was evaluated by the isoresponse curves. The significant factors were: enzyme concentration (linear and quadratic terms) and the interaction between enzyme concentration and Ni/Al molar ratio. Since the major obstacle for application of amperometric glucose biosensors is the interference signal resulting from other electro-oxidizable species present in the real matrices, such as ascorbate (AA), the use of different permselective membranes on Pt-LDHGOx modified electrode was discussed with the aim of improving biosensor selectivity and stability. Conventional membranes obtained using Nafion, glutaraldehyde (GA) vapours, GA-BSA were tested together with more innovative materials like palladium hexacyanoferrate (PdHCF) and titania hydrogels. Particular attention has been devoted to hydrogels, because they possess some attractive features, which are generally considered to favour biosensor materials biocompatibility and, consequently, the functional enzyme stability. The Pt-LDH-GOx-PdHCF hydrogel biosensor presented an anti-interferant ability so that to be applied for an accurate glucose analysis in blood. To further improve the biosensor selectivity, protective membranes containing horseradish peroxidase (HRP) were also investigated with the aim of oxidising the interferants before they reach the electrode surface. In such a case glucose determination was also accomplished in real matrices with high AA content. Furthermore, the application of a LDH containing nickel in the oxidised state was performed not only as a support for the enzyme, but also as anti-interferant sistem. The result is very promising and it could be the starting point for further applications in the field of amperometric biosensors; the study could be extended to other oxidase enzymes.

Präzisionsguss auf Basis von RP-Matritzen

Einige mit geringen Schichtstärken arbeitende Concept Modellierer und Rapid Prototyping Anlagen können Modelle für das Feingießverfahren mit verlorenem Modell erzeugen. Verkörpern die verlorenen Modelle die Geometrie von Formeinsätzen für Spritzgießwerkzeuge, können über den Feinguss Formeinsätze aus Aluminium hergestellt werden. Untersuchungen zielten dabei auf die detailgetreue Umsetzung filigraner Teile mit Freiformgeometrien. Kleine Abmessungen im Grenzbereich zwischen klassischem Formenbau und Mikrofertigung wurden dabei realisiert. Das Fräsen dieser Formeinsätze oder Elektroden ist zum Teil nicht möglich oder führt zu erhöhtem Aufwand. Gleichzeitig konnten sehr kurze Durchlaufzeiten erreicht werden. Auf demselben Weg konnten auch Senkerodierelektroden gegossen werden, die beim Aufbau von Werkzeugen höherer Lebensdauer genutzt wurden. Werden unterschiedliche Varianten oder mehrere identische Einsätze oder Elektroden zum Beispiel für Mehrfachwerkzeuge benötigt, werden die Zeitvorteile noch deutlicher. Die Funktion beider dargestellter Wege konnte durch den Spritzguss von Versuchsserien erfolgreich demonstriert werden.

Biogenic and environmental fluctuations of temperature and pH in a novel mesocosm concept ("Kiel Outdoor Benthocosms") April 2013 to September 2014

The Kiel Outdoor Benthocosm infrastructure (Kiel, Germany,N 54°19.8'; E 010°09.0') allows combining natural in-situ fluctuations on all environmental variables with the controlled manipulation of treatment factors. The environmental fluctuations are admitted by a continuous flow-through of fjord water. The treatment is applied by delta-treatments which shift the mean of target variables (temperature and pH in this case) while maintaining the frequency and amplitude of natural fluctuations. The data presented here show the treatment levels and the continuously logged temperature and pH conditions in the experimental tanks. The dynamics of temperature and pH are driven by (i) in situ variability, (ii) the treatments imposed and (iii) the biology of the biota in the tanks. These contained macroalgal communities with associated mesograzers, mussels, and sea stars. The data set comprised 5 experimental runs: spring experiment (4.4.-19.6.2013), summer experiment 1 (4.7.-17.9.2013), autumn experiment (10.10-17.12.2013), winter experiment (16.1. - 1.4.2014), summer experiment 2 (10.7. - 26.9.2014).

The design of a high pressure solvent extraction process using liquid ammonia as solvent

The literature on the potential use of liquid ammonia as a solvent for the extraction of aromatic hydrocarbons from mixtures with paraffins, and the application of reflux, has been reviewed. Reference is made to extractors suited to this application. A pilot scale extraction plant was designed comprising a Scm. diameter by 12Scm. high, 50 stage Rotating Disc Contactor with 2 external settlers. Provision was made for operation with, or without, reflux at a pressure of 10 bar and ambient temperature. The solvent recovery unit consisted of an evaporator, compressor and condenser in a refrigeration cycle. Two systems were selected for study, Cumene-n-Heptane-Ammonia and Toluene-Methylcyclohexane-Ammonia. Equlibrium data for the first system was determined experimentally in a specially-designed, equilibrium bomb. A technique was developed to withdraw samples under pressure for analysis by chromatography and titration. The extraction plant was commissioned with a kerosine-water system; detailed operating procedures were developed based on a Hazard and Operability Study. Experimental runs were carried out with both ternary ammonia systems. With the system Toluene-Methylcyclohexane-Ammonia the extraction plant and the solvent recovery facility, operated satisfactorily, and safely,in accordance with the operating procedures. Experimental data gave reasonable agreement with theory. Recommendations are made for further work with plant.

Design, modeling and construction of a novel ablative fast pyrolysis reactor and product collection system

The objective of this work was to design, construct and commission a new ablative pyrolysis reactor and a high efficiency product collection system. The reactor was to have a nominal throughput of 10 kg/11r of dry biomass and be inherently scalable up to an industrial scale application of 10 tones/hr. The whole process consists of a bladed ablative pyrolysis reactor, two high efficiency cyclones for char removal and a disk and doughnut quench column combined with a wet walled electrostatic precipitator, which is directly mounted on top, for liquids collection. In order to aid design and scale-up calculations, detailed mathematical modelling was undertaken of the reaction system enabling sizes, efficiencies and operating conditions to be determined. Specifically, a modular approach was taken due to the iterative nature of some of the design methodologies, with the output from one module being the input to the next. Separate modules were developed for the determination of the biomass ablation rate, specification of the reactor capacity, cyclone design, quench column design and electrostatic precipitator design. These models enabled a rigorous design protocol to be developed capable of specifying the required reactor and product collection system size for specified biomass throughputs, operating conditions and collection efficiencies. The reactor proved capable of generating an ablation rate of 0.63 mm/s for pine wood at a temperature of 525 'DC with a relative velocity between the heated surface and reacting biomass particle of 12.1 m/s. The reactor achieved a maximum throughput of 2.3 kg/hr, which was the maximum the biomass feeder could supply. The reactor is capable of being operated at a far higher throughput but this would require a new feeder and drive motor to be purchased. Modelling showed that the reactor is capable of achieving a reactor throughput of approximately 30 kg/hr. This is an area that should be considered for the future as the reactor is currently operating well below its theoretical maximum. Calculations show that the current product collection system could operate efficiently up to a maximum feed rate of 10 kg/Fir, provided the inert gas supply was adjusted accordingly to keep the vapour residence time in the electrostatic precipitator above one second. Operation above 10 kg/hr would require some modifications to the product collection system. Eight experimental runs were documented and considered successful, more were attempted but due to equipment failure had to be abandoned. This does not detract from the fact that the reactor and product collection system design was extremely efficient. The maximum total liquid yield was 64.9 % liquid yields on a dry wood fed basis. It is considered that the liquid yield would have been higher had there been sufficient development time to overcome certain operational difficulties and if longer operating runs had been attempted to offset product losses occurring due to the difficulties in collecting all available product from a large scale collection unit. The liquids collection system was highly efficient and modeling determined a liquid collection efficiency of above 99% on a mass basis. This was validated due to the fact that a dry ice/acetone condenser and a cotton wool filter downstream of the collection unit enabled mass measurements of the amount of condensable product exiting the product collection unit. This showed that the collection efficiency was in excess of 99% on a mass basis.

Fe-doped and -mediated graphitic carbon nitride nanosheets for enhanced photocatalytic performance under natural sunlight

Herein, we demonstrate the synthesis of highly efficient Fe-doped graphitic carbon nitride (g-C3N4) nanosheets via a facile and cost effective method. The synthesized Fe-doped g-C3N4 nanosheets were well characterized by various analytical techniques. The results revealed that the Fe exists mainly in the +3 oxidation state in the Fe-doped g-C3N4 nanosheets. Fe doping of g-C3N4 nanosheets has a great influence on the electronic and optical properties. The diffuse reflectance spectra of Fe-doped g-C3N4 nanosheets exhibit red shift and increased absorption in the visible light range, which is highly beneficial for absorbing the visible light in the solar spectrum. More significantly, the Fe-doped g-C3N4 nanosheets exhibit greatly enhanced photocatalytic activity for the degradation of Rhodamine B under sunlight irradiation. The photocatalytic activity of 2 mol% Fe-doped g-C3N4 nanosheets is almost 7 times higher than that of bulk g-C3N4 and 4.5 times higher than that of pure g-C3N4 nanosheets. A proposed mechanism for the enhanced photocatalytic activity of Fe-doped g-C3N4 nanosheets was investigated by trapping experiments. The synthesized photocatalysts are highly stable even after five successive experimental runs. The enhanced photocatalytic performance of Fe-doped g-C3N4 nanosheets is due to high visible light response, large surface area, high charge separation and charge transfer. Therefore, the Fe-doped g-C3N4 photocatalyst is a promising candidate for energy conversion and environmental remediation.

Ammonium excretion and respiration rate of tropical copepods and euphausiids measured during METEOR cruise M93, M97 and Maria S. Merian cruise MSM22

Respiration and ammonium excretion rates at different oxygen partial pressure were measured for calanoid copepods and euphausiids from the Eastern Tropical South Pacific and the Eastern Tropical North Atlantic. All specimens used for experiments were caught in the upper 400 m of the water column and only animals appearing unharmed and fit were used for experiments. Specimens were sorted, identified and transferred into aquaria with filtered, well-oxygenated seawater immediately after the catch and maintained for 1 to 13 hours prior to physiological experiments at the respective experimental temperature. Maintenance and physiological experiments were conducted in darkness in temperature-controlled incubators at 11, 13 or 23 degree C (±1). Before and during experiments, animals were not fed. Respiration and ammonium excretion rate measurements (both in µmol h-1 gDW-1) at varying oxygen concentrations were conducted in 12 to 60 mL gas-tight glass bottles. These were equipped with oxygen microsensors (ø 3 mm, PreSens Precision Sensing GmbH, Regensburg, Germany) attached to the inner wall of the bottles to monitor oxygen concentrations non-invasively. Read-out of oxygen concentrations was conducted using multi-channel fiber optic oxygen transmitters (Oxy-4 and Oxy-10 mini, PreSens Precision Sensing GmbH, Regensburg, Germany) that were connected via optical fibers to the outside of the bottles directly above the oxygen microsensor spots. Measurements were started at pre-adjusted oxygen and carbon dioxide levels. For this, seawater stocks with adjusted pO2 and pCO2 were prepared by equilibrating 3 to 4 L of filtered (0.2 µm filter Whatman GFF filter) and UV - sterilized (Aqua Cristal UV C 5 Watt, JBL GmbH & Co. KG, Neuhofen, Germany) water with premixed gases (certified gas mixtures from Air Liquide) for 4 hours at the respective experimental temperature. pCO2 levels were chosen to mimic the environmental pCO2 in the ETSP OMZ or the ETNA OMZ. Experimental runs were conducted with 11 to 15 trial incubations (1 or 2 animals per incubation bottle and three different treatment levels) and three animal-free control incubations (one per experimental treatment). During each run, experimental treatments comprised 100% air saturation as well as one reduced air saturation level with and without CO2. Oxygen concentrations in the incubation bottles were recorded every 5 min using the fiber-optic microsensor system and data recording for respiration rate determination was started immediately after all animals were transferred. Respiration rates were calculated from the slope of oxygen decrease over selected time intervals. Chosen time intervals were 20 to 105 min long. No respiration rate was calculated for the first 20 to 60 min after animal transfer to avoid the impact of enhanced activity of the animal or changes in the bottle water temperature during initial handling on the respiration rates and oxygen readings. Respiration rates were obtained over a maximum of 16 hours incubation time and slopes were linear at normoxia to mild hypoxia. Respiration rates in animal-free control bottles were used to correct for microbial activity. These rates were < 2% of animal respiration rates at normoxia. Samples for the measurement of ammonium concentrations were taken after 2 to 10 hours incubation time. Ammonium concentration was determined fluorimetrically (Holmes et al., 1999). Ammonium excretion was calculated as the concentration difference between incubation and animal-free control bottles. Some specimens died during the respiration and excretion rate measurements, as indicated by a cessation of respiration. No excretion rate measurements were conducted in this case, but the oxygen level at which the animal died was noted.

Robot navigation in dense crowds : statistical models and experimental studies of human robot cooperation

This thesis explores the problem of mobile robot navigation in dense human crowds. We begin by considering a fundamental impediment to classical motion planning algorithms called the freezing robot problem: once the environment surpasses a certain level of complexity, the planner decides that all forward paths are unsafe, and the robot freezes in place (or performs unnecessary maneuvers) to avoid collisions. Since a feasible path typically exists, this behavior is suboptimal. Existing approaches have focused on reducing predictive uncertainty by employing higher fidelity individual dynamics models or heuristically limiting the individual predictive covariance to prevent overcautious navigation. We demonstrate that both the individual prediction and the individual predictive uncertainty have little to do with this undesirable navigation behavior. Additionally, we provide evidence that dynamic agents are able to navigate in dense crowds by engaging in joint collision avoidance, cooperatively making room to create feasible trajectories. We accordingly develop interacting Gaussian processes, a prediction density that captures cooperative collision avoidance, and a "multiple goal" extension that models the goal driven nature of human decision making. Navigation naturally emerges as a statistic of this distribution.

Most importantly, we empirically validate our models in the Chandler dining hall at Caltech during peak hours, and in the process, carry out the first extensive quantitative study of robot navigation in dense human crowds (collecting data on 488 runs). The multiple goal interacting Gaussian processes algorithm performs comparably with human teleoperators in crowd densities nearing 1 person/m², while a state of the art noncooperative planner exhibits unsafe behavior more than 3 times as often as the multiple goal extension, and twice as often as the basic interacting Gaussian process approach. Furthermore, a reactive planner based on the widely used dynamic window approach proves insufficient for crowd densities above 0.55 people/m². We also show that our noncooperative planner or our reactive planner capture the salient characteristics of nearly any dynamic navigation algorithm. For inclusive validation purposes, we show that either our non-interacting planner or our reactive planner captures the salient characteristics of nearly any existing dynamic navigation algorithm. Based on these experimental results and theoretical observations, we conclude that a cooperation model is critical for safe and efficient robot navigation in dense human crowds.

Finally, we produce a large database of ground truth pedestrian crowd data. We make this ground truth database publicly available for further scientific study of crowd prediction models, learning from demonstration algorithms, and human robot interaction models in general.