Scheduling of straddle carriers in a container terminal

Report for the scientific sojourn at the University of California at Berkeley between September 2007 to February 2008. The globalization combined with the success of containerization has brought about tremendous increases in the transportation of containers across the world. This leads to an increasing size of container ships which causes higher demands on seaport container terminals and their equipment. In this situation, the success of container terminals resides in a fast transhipment process with reduced costs. For these reasons it is necessary to optimize the terminal’s processes. There are three main logistic processes in a seaport container terminal: loading and unloading of containerships, storage, and reception/deliver of containers from/to the hinterland. Moreover there is an additional process that ensures the interconnection between previous logistic activities: the internal transport subsystem. The aim of this paper is to optimize the internal transport cycle in a marine container terminal managed by straddle carriers, one of the most used container transfer technologies. Three sub-systems are analyzed in detail: the landside transportation, the storage of containers in the yard, and the quayside transportation. The conflicts and decisions that arise from these three subsystems are analytically investigated, and optimization algorithms are proposed. Moreover, simulation has been applied to TCB (Barcelona Container Terminal) to test these algorithms and compare different straddle carrier’s operation strategies, such as single cycle versus double cycle, and different sizes of the handling equipment fleet. The simulation model is explained in detail and the main decision-making algorithms from the model are presented and formulated.

Sistema de almacén y dispensación robotizada de productos farmacéuticos

Actualmente, las necesidades de mejora en gestión de stocks y la mayor disponibilidad de sistemas automáticos, están haciendo que muchas empresas inviertan en técnicas modernas para almacenamiento y manipulación de productos. Esta inquietud también ha llegado a las farmacias, que de forma lenta pero firme se van apuntando a su robotización. Uno de los principales problemas a los que se enfrentan las farmacias es la pérdida de tiempo en la gestión y búsqueda de medicamentos, provocando situaciones negativas como las esperas, la falta de tiempo para una atención más personalizada y como consecuencia, la pérdida de clientes. Este inconveniente y la necesidad de mejora en la gestión de los stocks han hecho que aparezcan los Sistemas de dispensación automática de productos farmacéuticos. El dispensador automático facilita el trabajo del farmacéutico al automatizar la búsqueda de la medicina requerida, aumentando la dedicación al cliente y reduciendo los tiempos no productivos y las colas. El presente estudio desarrolla un sistema de dispensación automático de fármacos aplicado a farmacias con una rotación de medicamentos media/ baja, valorando tanto su viabilidad técnica como económica. El almacén propuesto es de tipo caótico con sistema de carga, almacenamiento y descarga completamente automáticos. La mayoría de diseños y conceptos expuestos en este trabajo son de desarrollo propio del autor con el único objetivo de la búsqueda de nuevas soluciones para conseguir un sistema de almacenamiento efectivo y de máximo rendimiento.

Sistema de almacén y dispensación robotizada de productos farmacéuticos

Actualmente, las necesidades de mejora en gestión de stocks y la mayor disponibilidad de sistemas automáticos, están haciendo que muchas empresas inviertan en técnicas modernas para almacenamiento y manipulación de productos. Esta inquietud también ha llegado a las farmacias, que de forma lenta pero firme se van apuntando a su robotización. Uno de los principales problemas a los que se enfrentan las farmacias es la pérdida de tiempo en la gestión y búsqueda de medicamentos, provocando situaciones negativas como las esperas, la falta de tiempo para una atención más personalizada y como consecuencia, la pérdida de clientes. Este inconveniente y la necesidad de mejora en la gestión de los stocks han hecho que aparezcan los Sistemas de dispensación automática de productos farmacéuticos. El dispensador automático facilita el trabajo del farmacéutico al automatizar la búsqueda de la medicina requerida, aumentando la dedicación al cliente y reduciendo los tiempos no productivos y las colas. El presente estudio desarrolla un sistema de dispensación automático de fármacos aplicado a farmacias con una rotación de medicamentos media/ baja, valorando tanto su viabilidad técnica como económica. El almacén propuesto es de tipo caótico con sistema de carga, almacenamiento y descarga completamente automáticos. La mayoría de diseños y conceptos expuestos en este trabajo son de desarrollo propio del autor con el único objetivo de la búsqueda de nuevas soluciones para conseguir un sistema de almacenamiento efectivo y de máximo rendimiento.

Comportamiento tribomecánico de sistemas de sustrato: recubrimiento duros

En aplicaciones como la conformación en frío, donde los metales duros recubiertos con películas de naturaleza cerámica son ampliamente empleados, la existencia de un contacto mecánico repetitivo induce tensiones Hertzianas y origina el fallo por fatiga. En este trabajo, se investigan diversos recubrimientos cerámicos depositados por deposición física desde fase vapor sobre calidades diferentes de metal duro y un acero rápido pulvimetalúrgico para evaluar sus respectivas respuesta al contacto y comportamiento a fatiga. El trabajo experimental incluye la caracterización de los sistemas mediante ensayos de rayado y nanoindentación y la evaluación de las curvas tensión-deformación de indentación esférica de los sustratos, tanto desnudos como recubiertos, poniendo especial atención en determinar las tensiones de contacto críticas asociadas a la deformación plástica y a la aparición de grietas circulares en la superficie recubierta. A este estudio, le siguen numerosos ensayos a fatiga a cargas inferiores a aquéllas identificadas como críticas bajo carga monotónica y para un número de ciclos comprendido entre 1.000 y 1.000.000 de ciclos. Los resultados experimentales indican que las películas cerámicas no parecen desempeñar un papel relevante en la aparición de la cedencia plástica, siendo la deformación plástica global controlada por la deformación del sustrato. No obstante, para tensiones elevadas de indentación durante el régimen plástico, existe la aparición de grietas circulares en los recubrimientos cerámicos. Además, la aparición de las mismas es sensible a la fatiga por contacto. Este análisis mecánico se complementa con una inspección detallada del daño generado en profundidad y superficie.

Experimental investigation of transient natural convection cooling of high prandtl number fluid with variable viscosity

Report for the scientific sojourn at the James Cook University, Australia, between June to December 2007. Free convection in enclosed spaces is found widely in natural and industrial systems. It is a topic of primary interest because in many systems it provides the largest resistance to the heat transfer in comparison with other heat transfer modes. In such systems the convection is driven by a density gradient within the fluid, which, usually, is produced by a temperature difference between the fluid and surrounding walls. In the oil industry, the oil, which has High Prandtl, usually is stored and transported in large tanks at temperatures high enough to keep its viscosity and, thus the pumping requirements, to a reasonable level. A temperature difference between the fluid and the walls of the container may give rise to the unsteady buoyancy force and hence the unsteady natural convection. In the initial period of cooling the natural convection regime dominates over the conduction contribution. As the oil cools down it typically becomes more viscous and this increase of viscosity inhibits the convection. At this point the oil viscosity becomes very large and unloading of the tank becomes very difficult. For this reason it is of primary interest to be able to predict the cooling rate of the oil. The general objective of this work is to develop and validate a simulation tool able to predict the cooling rates of high Prandtl fluid considering the variable viscosity effects.

Development of an optimized methodology for tensile testing of carbon steels in hydrogen environment

The study was performed at OCAS, the Steel Research Centre of ArcelorMittal for the Industry market. The major aim of this research was to obtain an optimized tensile testing methodology with in-situ H-charging to reveal the hydrogen embrittlement in various high strength steels. The second aim of this study has been the mechanical characterization of the hydrogen effect on hight strength carbon steels with varying microstructure, i.e. ferrite-martensite and ferrite-bainite grades. The optimal parameters for H-charging - which influence the tensile test results (sample geometry type of electrolyte, charging methods effect of steel type, etc.) - were defined and applied to Slow Strain Rate testing, Incremental Step Loading and Constant Load Testing. To better understand the initiation and propagation of cracks during tensile testing with in-situ H-charging, and to make the correlation with crystallographic orientation, some materials have been analyzed in the SEM in combination with the EBSD technique. The introduction of a notch on the tensile samples permits to reach a significantly improved reproducibility of the results. Comparing the various steel grades reveals that Dual Phase (ferrite-martensite) steels are more sensitive to hydrogen induced cracking than the FB (ferritic-bainitic) ones. This higher sensitivity to hydrogen was found back in the reduced failure times, increased creep rates and enhanced crack initiation (SEM) for the Dual Phase steels in comparison with the FB steels.

Efectividad técnica y frecuencia de golpeo en el tenis femenino de élite. Estudio de caso.

La efectividad técnica de golpeo (ET) se ha identificado como un buen parámetro pronosticador del rendimiento en el tenis y la frecuencia de golpeo de pelotas (FGP), aunque es un parámetro de carga técnica y condicional poco utilizado, es un indicador capaz de detectar diferencias en el juego. El objetivo del estudio fue caracterizar la ET en función de la FGP en una jugadora profesional de máximo nivel competitivo, utilizando un protocolo maximal, continuo de intensidad progresiva y registrando paralelamente parámetros de carga y fisiológicos. Se ejecutaron un total de 212 golpes obteniendo una ET del 81.6 % de aciertos, los valores oscilaron a lo largo de la prueba entre un rango del 81.6 a 93.3 % de aciertos y únicamente disminuyeron hasta el 70.7 % en el último periodo alcanzado (UP) y a partir del punto de disminución de ET (PDET). Se alcanzó una FGP máxima (FGPmax) de 21 golpes·min-1, una duración de la prueba (DP) de 14:07 (min:s) correspondiente a un UP de 7. Se concluye que la jugadora presenta una elevada ET y una importante capacidad de mantener unos elevados indicies de ET, a pesar del incremento de la FGP y de la fatiga metabólica asociada.

Bit loading for MIMO with statistical channel information at the transmitter and ZF receivers

For single-user MIMO communication with uncoded and coded QAM signals, we propose bit and power loading schemes that rely only on channel distribution information at the transmitter. To that end, we develop the relationship between the average bit error probability at the output of a ZF linear receiver and the bit rates and powers allocated at the transmitter. This relationship, and the fact that a ZF receiver decouples the MIMO parallel channels, allow leveraging bit loading algorithms already existing in the literature. We solve dual bit rate maximization and power minimization problems and present performance resultsthat illustrate the gains of the proposed scheme with respect toa non-optimized transmission.

Complications of guided surgery and immediate loading in oral implantology: a report of 12 cases

Objectives: The growing interest in minimally invasive surgery, together with the possibility of fitting prostheses with immediate function, have led to the development of software capable of planning and manufacturing a surgical guide and prosthesis that can be placed upon conclusion of the implant surgery step. The present study evaluates the surgical and prosthetic complications of implant treatment with the guided surgery technique, together with patient comfort during and after treatment. Patients and methods: A retrospective observational study was made of 19 patients with partially or totally edentulous upper and/or lower maxillae, involving the placement of a total of 122 implants. All cases were planned and operated upon with the guided surgery technique. Results: A total of 122 implants were placed in 14 males and 5 females. The intraoperative surgical complications comprised a lack of primary stability, while the postoperative complications consisted of infections and a lack of implant osteointegration. Ten implants failed. The prosthetic complications in turn comprised loosening of the provisional prosthesis screws, prosthesis tooth fracture, and a lack of passive fit of the immediate prosthesis. The degree of patient satisfaction was evaluated using a verbal scale. Conclusions: Implant restoration with the guided surgery technique and immediate functional loading is a predictable procedure, provided patient selection and the surgical technique are adequate, affording lesser postoperative morbidity and increased patient satisfaction thanks to the immediate restoration of esthetics and function

Protein phosphatase inhibition assays for okadaic acid detection in shellfish: matrix effects, applicability and comparison with LC-MS/MS analysis

The applicability of the protein phosphatase inhibition assay (PPIA) to the determination of okadaic acid (OA) and its acyl derivatives in shellfish samples has been investigated, using a recombinant PP2A and a commercial one. Mediterranean mussel, wedge clam, Pacific oyster and flat oyster have been chosen as model species. Shellfish matrix loading limits for the PPIA have been established, according to the shellfish species and the enzyme source. A synergistic inhibitory effect has been observed in the presence of OA and shellfish matrix, which has been overcome by the application of a correction factor (0.48). Finally, Mediterranean mussel samples obtained from Rı´a de Arousa during a DSP closure associated to Dinophysis acuminata, determined as positive by the mouse bioassay, have been analysed with the PPIAs. The OA equivalent contents provided by the PPIAs correlate satisfactorily with those obtained by liquid chromatography–tandem mass spectrometry (LC–MS/MS).

Filtrations by complete ideals and applications

Infinitely near base points and Enriques' unloading procedure are used to construct filtrations by complete ideals of C{x, y}. It follows a procedure for getting generators of the integral closure of an ideal.

A simple halide-to-anion exchange method for heteroaromatic salts and ionic liquids

A broad and simple method permitted halide ions in quaternary heteroaromatic and ammonium salts to be exchanged for a variety of anions using an anion exchange resin (A− form) in non-aqueous media. The anion loading of the AER (OH− form) was examined using two different anion sources, acids or ammonium salts, and changing the polarity of the solvents. The AER (A− form) method in organic solvents was then applied to several quaternary heteroaromatic salts and ILs, and the anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Relying on the hydrophobicity of the targeted ion pair for the counteranion swap, organic solvents with variable polarity were used, such as CH3OH, CH3CN and the dipolar nonhydroxylic solvent mixture CH3CN:CH2Cl2 (3:7) and the anion exchange was equally successful with both lipophilic cations and anions.

A simple halide-to-anion exchange method for heteroaromatic salts and ionic liquids

A broad and simple method permitted halide ions in quaternary heteroaromatic and ammonium salts to be exchanged for a variety of anions using an anion exchange resin (A− form) in non-aqueous media. The anion loading of the AER (OH− form) was examined using two different anion sources, acids or ammonium salts, and changing the polarity of the solvents. The AER (A− form) method in organic solvents was then applied to several quaternary heteroaromatic salts and ILs, and the anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Relying on the hydrophobicity of the targeted ion pair for the counteranion swap, organic solvents with variable polarity were used, such as CH3OH, CH3CN and the dipolar nonhydroxylic solvent mixture CH3CN:CH2Cl2 (3:7) and the anion exchange was equally successful with both lipophilic cations and anions.

Effects of inorganic nitrogen (NH4Cl) and biodegradable organic carbon (CH3COONa) additions on a pilot-scale seawater biofilter

Biofilters degrade only a small fraction of the natural organic matter (NOM) contained in seawater which is the leading cause of biofouling in downstream processes. This work studies the effects of chemical additions on NOM biodegradation by biofilters. In this work, biofiltration of seawater with an empty bed contact time (EBCT) of 6 min and a hydraulic loading rate of 10 m h-1 reduces the biological oxygen demand (BOD7) by 8%, the dissolved organic carbon (DOC) by 6% and the UV absorbance at 254 nm (A254) by 7%. Different amounts of ammonium chloride are added to the seawater (up to twice the total dissolved nitrogen in untreated seawater) to study its possible effect on the removal of NOM by a pilot-scale biofilter. Seawater is amended with different amounts of easily biodegradable dissolved organic carbon (BDOC) supplied as sodium acetate (up to twice the DOC) for the same purpose. The results of this work reveal that the ammonium chloride additions do not significantly affect NOM removal and the sodium acetate is completely consumed by the biofiltration process. For both types of chemical additions, the BOD7, DOC and A254 in the outlet stream of the biofilter are similar to the values for the untreated control. These results indicate that this biofilter easily removes the BDOC from the seawater when the EBCT is not above 6 min. Furthermore, nitrogen does not limit the NOM biodegradation in seawater under these experimental conditions.