Prismatic dentine in the Australian lungfish, Neoceratodus forsteri (Osteichthyes : Dipnoi)

The Australian lungfish, Neoceratodus forsteri, has a dentition consisting of enamel, mantle dentine and bone, enclosing circumdenteonal, core and interdenteonal dentines. Branching processes from cells that produce interdenteonal dentine leave the cell surface at different angles, with collagen fibrils aligned parallel to the long axis of each process. In the interdenteonal dentine, crystals of calcium hydroxyapatite, form within fibrils of collagen, and grow within a matrix of non-collagenous protein. Crystals are aligned parallel to the cell process, as are the original collagen fibrils. Because the processes are angled to the cell surface, the crystals within the core or interdenteonal dentine are arranged in bundles set at angles to each other. Apatite crystals in circumdenteonal dentine are finer and denser than those of the interdenteonal dentine, and form outside the fibrils of collagen. In mature circumdenteonal dentine the crystals of circumdenteonal dentine form a dense tangled mass, linked to interdenteonal dentine by isolated crystals. The functional lungfish tooth plate contains prisms of large apatite crystals in the interdenteonal dentine and masses of fine tangled crystals around each denteon. This confers mechanical strength on a structure with little enamel that is subjected to heavy wear. (c) 2006 Elsevier Ltd. All rights reserved.

Entropy generation for microscale forced convection: effects of different thermal boundary conditions, velocity slip, temperature jump, viscous dissipation, and duct geometry

This work presents closed form solutions for fully developed temperature distribution and entropy generation due to forced convection in microelectromechanical systems (MEMS) in the Slip-flow regime, for which the Knudsen number lies within the range 0.001

Heat and mass transfer in membrane distillation used for desalination with slip flow

A theoretical model for the transport phenomena in an air gap membrane distillation is presented. The model is based on the conservation equations for the mass, momentum, energy and species within the feed water solution as well as on the mass and energy balances on the membrane sides. The slip flow occurs due to the hydrophobic properties of the membrane. The slip boundary condition applied on the feed saline solution-membrane interface is taken into consideration showing its effects on process parameters particularly permeate flow, heat transfer coefficient and thermal efficiency. The theoretical model was validated with available experimental data and was found to be in good agreement especially when the slip condition is introduced. Increasing slip length from zero to 200 μm was found to increase the permeate flux and the thermal efficiency by 33% and 1.7% respectively.

Operation sequencing optimization for five-axis prismatic parts using a particle swarm optimization approach

Operation sequencing is one of the crucial tasks in process planning. However, it is an intractable process to identify an optimized operation sequence with minimal machining cost in a vast search space constrained by manufacturing conditions. Also, the information represented by current process plan models for three-axis machining is not sufficient for five-axis machining owing to the two extra degrees of freedom and the difficulty of set-up planning. In this paper, a representation of process plans for five-axis machining is proposed, and the complicated operation sequencing process is modelled as a combinatorial optimization problem. A modern evolutionary algorithm, i.e. the particle swarm optimization (PSO) algorithm, has been employed and modified to solve it effectively. Initial process plan solutions are formed and encoded into particles of the PSO algorithm. The particles 'fly' intelligently in the search space to achieve the best sequence according to the optimization strategies of the PSO algorithm. Meanwhile, to explore the search space comprehensively and to avoid being trapped into local optima, several new operators have been developed to improve the particle movements to form a modified PSO algorithm. A case study used to verify the performance of the modified PSO algorithm shows that the developed PSO can generate satisfactory results in optimizing the process planning problem. © IMechE 2009.

Computer program for the analysis of non-prismatic beams

One of the major problems in the analysis of beams with Moment of Inertia varying along their length, is to find the Fixed End Moments, Stiffness, and Carry-Over Factors. In order to determine Fixed End Moments, it is necessary to consider the non-prismatic member as integrated by a large number of small sections with constant Moment of Inertia, and to find the M/EI values for each individual section. This process takes a lot of time from Designers and Structural Engineers. The object of this thesis is to design a computer program to simplify this repetitive process, obtaining rapidly and effectively the Final Moments and Shears in continuous non-prismatic Beams. For this purpose the Column Analogy and the Moment Distribution Methods of Professor Hardy Cross have been utilized as the principles toward the methodical computer solutions. The program has been specifically designed to analyze continuous beams of a maximum of four spans of any length, integrated by symmetrical members with rectangular cross sections and with rectilinear variation of the Moment of Inertia. Any load or combination of uniform and concentrated loads must be considered. Finally sample problems will be solved with the new Computer Program and with traditional systems, to determine the accuracy and applicability of the Program.

Coseismic horizontal slip revealed by sheared clastic dikes in the Dead Sea Basin

Peer reviewed

Combined Conduction-Convection-Radiation Heat Transfer of Slip Flow inside a Micro-channel Filled with a Cellular Porous Material

Combined conduction–convection–radiation heat transfer is investigated numerically in a micro-channel filled with a saturated cellular porous medium, with the channel walls held at a constant heat flux. Invoking the velocity slip and temperature jump, the thermal behaviour of the porous–fluid system are studied by considering hydrodynamically fully developed flow and applying the Darcy–Brinkman flow model. One energy equation model based on the local thermal equilibrium condition is adopted to evaluate the temperature field within the porous medium. Combined conduction and radiation heat transfer is treated as an effective conduction process with a temperature-dependent effective thermal conductivity. Results are reported in terms of the average Nusselt number and dimensionless temperature distribution, as a function of velocity slip coefficient, temperature jump coefficient, porous medium shape parameter and radiation parameters. Results show that increasing the radiation parameter (Tr)(Tr) and the temperature jump coefficient flattens the dimensionless temperature profile. The Nusselt numbers are more sensitive to the variation in the temperature jump coefficient rather than to the velocity slip coefficient. Such that for high porous medium shape parameter, the Nusselt number is found to be independent of velocity slip. Furthermore, it is found that as the temperature jump coefficient increases, the Nusselt number decrease. In addition, for high temperature jump coefficients, the Nusselt number is found to be insensitive to the radiation parameters and porous medium shape parameter. It is also concluded that compared with the conventional macro-channels, wherein using a porous material enhances the rate of heat transfer (up to about 40 % compared to the clear channel), insertion of a porous material inside a micro-channel in slip regime does not effectively enhance the rate of heat transfer that is about 2 %.

Visual results with the use of prismatic lenses in the treatment of congenital nystagmus: a clinical case

Purpose: It is important to establish a differential diagnosis between the different types of nystagmus, in order to give the appropriate clinical approach to every situation and to improve visual acuity. The nystagmus is normally blocked when the eyes are positioned in a particular way. This makes the child adopt a posture of ocular torticollis that reduces the nistagmiformes movements, improving the vision in this position. A way to promote the blocking of the nystagmic movements is by using prismatic lenses with opposite bases, to block or minimize the oscillatory movements. This results in a vision improvement and it reduces the anomalous head position. There is limited research on the visual results in children with nystagmus after using prisms with opposing bases. Our aim is to describe the impact on the visual acuity (VA ) of theprescription prism lenses in a nystagmus patient starting at 3 months of age. Methods: Case report on thirty month old caucasian male infant, with normal growth and development for their age, with an early onset of horizontal nystagmus at 3 months of age. Ophthalmic examination included slit lamp examination, fundus, refractive study, electrophysiological and magnetic resonance tests, measurement of VA over time with the Teller Acuity Cards (TAC ) in the distance agreed for the age. At age ten months, the mother noted a persistent turn to the right of the child’s head, which became increasingly more severe along the months. There’s no oscillopcia. At 24 months, an atropine refraction showed the following refractive error: 0D.: -1,50, OS: -0,50 and prismatic lens adapting OD 8 Δ nasal base and OE 8 Δ temporal base. Results: Thirty month old child, with adequate development for their age, with onset of idiopatic horizontal nystagmus, at 3 months of age. Normal ocular fundus and magnetic ressoance without alterations, sub-normal results in electrophysiological tests and VA with values below normal for age. At 6 months OD 20/300; OE 20/400; OU 20/300. At 9 months OD 20/250; OE 20/300; OU 20/150 (TAC a 38 cm). At 18 months OD 20/200; OE 20/100; OU 20/80 (TAC at 38 cm), when the head is turned to the right and the eyes in levoversão, the nystagmus decreases in a “neutral” area. At 24 month, with the prismatic glasses, OD 20/200 OE 20/100, OU20/80 (TAC at 54 cm, reference value is 20/30 – 20/100 para OU e 20/40 – 20/100 monocular), there was an increase in the visual acuity. The child did visual stimulation with multimedia devices and using glasses. After adaptation of prisms: at 30 months VA (with Cambridge cards) OD e OE = 6/18. The child improved the VA and reduced the anomalous head position. There is also improvement in mobility and fine motricity. Conclusion: Prisms with opposing bases., were used in the treatment of idiopathic nystagmus. Said prisms were adapted to reduce the skewed position of the head, and to improve VA and binocular function. Monitoring of visual acuity and visual stimulation was done using electronic devices. Following the use of prismatic, the patient improved significantly VA and the anomalous head position was reduced.

Map of Nassau Heights in the village of Newtown, Queens County, L.I. : formerly the Brettonnierre Farm, now the Caldwall Farm : about 4 miles from Peck Slip Ferry in Williamsburgh /

Cadastral survey map of proposed streets and lots, showing dimensions, lot numbers, and existing buildings.

Light losses in hollow, prismatic light guides related to prim defects: a transmittance model

Hollow, cylindrical, prismatic light guides (CPLGs) are optical components that, using total internal reflection (TIR), are able to transmit high-diameter light beams in daylight and artificial lighting applications without relevant losses. It is necessary to study the prism defects of their surfaces to quantify the behavior of these optical components. In this Letter, we analyze a CPLG made of a transparent dielectric material. Scanning electron microscopy (SEM) and the topographic optical profilometry by absorption in fluids (TOPAF) imaging technique are conducted to determine if there are defects in the corners of the prisms. A model for light guide transmittance that is dependent on prism defects is proposed. Finally, a simulation and an experimental study are carried out to check the validity of the proposed model.

Diseño de un Plan de Mercadeo para Slip Ltda. Asesores de Seguros

El propósito general de este documento es realizar un plan de mercadeo que ayude a mantener e incrementar el número de clientes de la empresa, traduciéndose esto en un incremento progresivo de las ventas de la compañía Slip Ltda. A través del diseño y generación de estrategias de mercadeo basadas en la explotación del portafolio de servicios actuales así como la ampliación de la gama de seguros ofrecidos actualmente por la empresa con el fin último de atraer un mayor número de nuevos clientes, evitar la posible absorción de la compañía por parte de otras empresas multinacionales, asegurar la sostenibilidad del negocio a través del tiempo y la optimización de las utilidades de la organización a través de las primas devengadas. Por consiguiente, el trabajo consiste en: Analizar el entorno económico de la empresa Slip Ltda. Mostrando la situación actual del sector y analizando las oportunidades y amenazas que se presentan, identificación de los nichos de mercado objetivo hacia los cuales se dirigirán las estrategias y los servicios que se buscarán potenciar, exploración de la capacidad de la empresa de generar valor agregado a sus clientes, definición de estrategias y tácticas que orienten a la compañía a obtener resultados a partir de las herramientas del marketing mix y planteamiento y establecimiento de un calendario para la aplicación de las estrategias junto con la proyección del presupuesto requerido para ello.

Extensional orogenic collapse captured by strike-slip tectonics:

The late Paleozoic collision between Gondwana and Laurussia resulted in the polyphase deformation and magmatism that characterizes the Iberian Massif of the Variscan orogen. In the Central Iberian Zone, initial con- tinental thickening (D1; folding and thrusting) was followed by extensional orogenic collapse (D2) responsible for the exhumation of high-grade rocks coeval to the emplacement of granitoids. This study presents a tectonometamorphic analysis of the Trancoso-Pinhel region (Central Iberian Zone) to ex- plain the processes in place during the transition froman extension-dominated state (D2) to a compression-dom- inated one (D3).Wereveal the existence of low-dipping D2 extensional structures later affected by several pulses of subhorizontal shortening, each of them typified by upright folds and strike-slip shearing (D3, D4 and D5, as identified by superimposition of structures). The D2 Pinhel extensional shear zone separates a low-grade domain from an underlying high-grade domain, and it contributed to the thermal reequilibration of the orogen by facil- itating heat advection from lower parts of the crust, crustal thinning, decompression melting, and magma intru- sion. Progressive lessening of the gravitational disequilibrium carried out by this D2 shear zone led to a switch from subhorizontal extension to compression and the eventual cessation and capture of the Pinhel shear zone by strike-slip tectonics during renewed crustal shortening. High-grade domains of the Pinhel shear zone were folded together with low-grade domains to define the current upright folded structure of the Trancoso-Pinhel re- gion, the D3 Tamames-Marofa-Sátão synform. Newdating of syn-orogenic granitoids (SHRIMP U\\Pb zircon dat- ing) intruding the Pinhel shear zone, together with the already published ages of early extensional fabrics constrain the functioning of this shear zone to ca. 331–311 Ma, with maximum tectonomagmatic activity at ca. 321–317 Ma. The capture and apparent cessation of movement of the Pinhel shear zone occurred at ca. 317– 311 Ma.

Bifocal lens control of myopia progression in children

This research investigated underlying issues that were critical to the success of the bifocal trial and comprised of three studies. The first study evaluated if Chinese-Canadian children were suitable subjects for the bifocal trial. The high prevalence of myopia in Chinese children suggests that genetic input plays a role in myopia development, but the rapid increase in prevalence over the last few decades indicates environmental factors are also important. Since this bifocal trial was conducted in Canada, this work aimed to determine whether Chinese children who had migrated to Canada would still have high myopia prevalence and a high rate of myopia progression. The second study determined the optimal bifocal lens power for myopia treatment and the effect of incorporating base-in prism into the bifocal. In the majority of published myopia control studies, the power of the prescribed near addition was usually predetermined in the belief that the near addition would always help to improve the near focus. In fact, the effect of near addition on the accommodative error might be quite different even for individuals in which the same magnitude of accommodation lag had been measured. Therefore, this work was necessary to guide the selection of bifocal and prism powers most suitable for the subsequent bifocal trial. The third study, the ultimate goal of this research, was to conduct a longitudinal clinical trial to determine if bifocals and prismatic bifocals could control myopia progression in children.