Thermal Error Modelling of a CNC Machine Tool Feed Drive System using FEA Method

Recirculating ball screw systems are commonly used in machine tools and are one of the major heat sources which cause considerable thermal drift in CNC machine tools. Finite Element Analysis (FEA) method has been used successfully in the past to model the thermal characteristics of machine tools with promising results. Since FEA predictions are highly dependent on the efficacy of numerical parameters including the surrounding Boundary Conditions (BC), this study emphasises on an efficient modelling method to obtain optimised numerical parameters for acquiring a qualitative response from the feed drive system model. This study was performed on a medium size Vertical Machining Centre (VMC) feed drive system in which two parameter dentification methods have been employed; the general prediction method based on formulae provided by OEMs, and the energy balance method. The parameters obtained from both methods were applied to the FEA model of the machine feed drive system and validated against experimental results. Correlation with which was increased from 70 % to 80 % using the energy balance method

Ahmed’as Ibn Fadlan’as ir Bayard’as Taylor’as – kelionių literatūros kūrėjai ar vertėjai?

In this article, two works of travel writing, Resala (922) by Ahmed Ibn Fadlan and Travels in Arabia (1889) by Bayard Taylor, are explored to show how the genre as a whole serves as one way of translating culture in order to better understand and discover it. It examines how ideology affects cultural translation in travel writing and how this leads to othering. We begin with close readings of the texts for major content themes, including religion, sex, traditions, etc. These are analyzed for instantiations of inaccurate cultural translation, ideology, and othering. The use of pronouns, nouns, and adjectives is looked at to explore their othering effect. The results show that inaccurate cultural translations are sometimes influenced by ideology and usually lead to othering. The analyzed samples of travel writing rather reveal the predominant mindsets and leanings of their authors and cultures of their origin than those they attempt to introduce to their readers.Straipsnyje, pasitelkiant du kelionių literatūros tekstus – Ahmed’o Ibn Fadlan’o knygą apie jo kelionę su misija į Rusiją Resala (922) bei Bayard’o Taylor’o kelionių po arabų šalis užrašus Travels in Arabia (1889), – gilinamasi į tai, kaip kelionių literatūros žanras funkcionuoja kaip tam tikras kultūros vertimas siekiant tą kultūrą geriau suprasti ir pristatyti skaitytojams. Keliamas tikslas išsiaiškinti, kaip kultūrinį vertimą kelionių literatūroje veikia ideologija ir kaip dėl šio poveikio pristatomoji kultūra sukitinama. Pirma tekstai atidžiai skaitomi siekiant išskirti pagrindines atsikartojančias temas: religiją, seksą, tradicijas ir kitas. Analizuojant šių temų raišką, išrenkami netikslaus kultūrinio vertimo, ideologijos raiškos ir sukitinimo pavyzdžiai. Tiriama, kokį sukitinamąjį poveikį turi įvardžių, daiktavardžių ir būdvardžių vartosena. Tyrimas rodo, kad abiejuose tekstuose klaidingą kultūrinį vertimą kai kuriais atvejais lemia autorių ideologija – toks vertimas įtvirtina pristatomos kultūros kaip „Kito“ kultūros įvaizdį. Šie analizuojami kelionių literatūros pavyzdžiai labiau atskleidžia pačių autorių bei jų kilmės kultūrų, o ne skaitytojams pristatomų kultūrų nuostatas ir pažiūras

Implementation of the block-Krylov boundary flexibility method of component synthesis

A method of dynamic substructuring is presented which utilizes a set of static Ritz vectors as a replacement for normal eigenvectors in component mode synthesis. This set of Ritz vectors is generated in a recurrence relationship, which has the form of a block-Krylov subspace. The initial seed to the recurrence algorithm is based on the boundary flexibility vectors of the component. This algorithm is not load-dependent, is applicable to both fixed and free-interface boundary components, and results in a general component model appropriate for any type of dynamic analysis. This methodology was implemented in the MSC/NASTRAN normal modes solution sequence using DMAP. The accuracy is found to be comparable to that of component synthesis based upon normal modes. The block-Krylov recurrence algorithm is a series of static solutions and so requires significantly less computation than solving the normal eigenspace problem

Uso de métodos moleculares para la identificación de especies de levaduras aisladas de fermentaciones de aceitunas de mesa producidas tradicionalmente en Kahramanmaraş

In this study, yeast species involved in the naturally fermented green table olive produced in Southern Turkey were investigated. Table olive samples were prepared with regional olive cultivars and traditional methods were employed in the production. Yeasts were isolated from the brines of the samples at the late fermentation stage and identified at the species level by the DNA sequences of the D1/D2 domain of 26S rRNA genes. The D1/D2 domains were amplified by PCR, sequenced and compared to reference sequences deposited in the NCBI database. According to the results, isolated yeasts belonged to the Candida, Debaryomyces, and Rhodotorula genera and salt tolerant species were dominant as the salt content of the brines exceeded 11%. Among the determined species, Candida oleophila was the most dominant one and it was thought that isolated strains of Candida oleophila may be taken into consideration to be used as starter culture in table olive production.En este estudio, se investigaron las especies de levaduras que intervinieron en la fermentación natural de aceitunas verdes de mesa del sur de Turquía. Las muestras de aceitunas de mesa se prepararon con cultivares de aceitunas regionales y se emplearon métodos tradicionales en la producción. Las levaduras se aislaron de las salmueras de las muestras en la última etapa de fermentación y se identificaron a nivel de especie mediante las secuencias de ADN del dominio D1/D2 de los genes 26S rRNA. Los dominios D1/D2 fueron amplificados por PCR, secuenciados y comparados con las secuencias de referencia depositadas en la base de datos del NCBI. Según los resultados, las levaduras aisladas pertenecen a los géneros Candida, Debaryomyces y Rhodotorula, y las especies tolerantes a la sal fueron dominantes, ya que el contenido de sal de las salmueras superó el 11 %. Entre las especies determinadas, Candida oleophila fue la dominante y se pensó que las cepas aisladas de Candida oleophila podrían tenerse en cuenta para su uso como cultivo iniciador en la producción de aceitunas de mesa

Co-Application of Corticosterone and Growth Hormone Upregulates NR2B Protein and Increases the NR2B:NR2A Ratio and Synaptic Transmission in the Hippocampus

Objectives: This in vitro study aimed to investigate the possible mechanism underlying the protective effect of growth hormone (GH) on hippocampal function during periods of heightened glucocorticoid exposure. Methods: This study was conducted between January and June 2005 at the Joan C. Edwards School of Medicine, Marshall University, in Huntington, West Virginia, USA. The effects of the co-application of GH and corticosterone (CORT) were tested at different concentrations on the field excitatory postsynaptic potentials (fEPSPs) of the hippocampal slices of rats in two different age groups. Changes in the protein expression of N-methyl-D-aspartate receptor (NMDAR) subunits NR1, NR2B and NR2A were measured in hippocampal brain slices treated with either artificial cerebrospinal fluid (ACSF), low doses of CORT alone or both CORT and GH for three hours. Results: The co-application of CORT and GH was found to have an additive effect on hippocampal synaptic transmission compared to either drug alone. Furthermore, the combined use of low concentrations of GH and CORT was found to have significantly higher effects on the enhancement of fEPSPs in older rats compared to young ones. Both GH and CORT enhanced the protein expression of the NR2A subunit. Simultaneous exposure to low concentrations of GH and CORT significantly enhanced NR2B expression and increased the NR2B:NR2A ratio. In contrast, perfusion with CORT alone caused significant suppression in the NR1 and NR2B protein expression and a decrease in the NR2B:NR2A ratio. Conclusion: These results suggest that NMDARs provide a potential target for mediating the GH potential protective effect against stress and age-related memory and cognitive impairment

Experimental Violation of Bell's Inequality in Spatial-Parity Space

We report the first experimental violation of Bell's inequality in the spatial domain using the Einstein--Podolsky--Rosen state. Two-photon states generated via optical spontaneous parametric downconversion are shown to be entangled in the parity of their one-dimensional transverse spatial profile. Superpositions of Bell states are prepared by manipulation of the optical pump's transverse spatial parity--a classical parameter. The Bell-operator measurements are made possible by devising simple optical arrangements that perform rotations in the one-dimensional spatial-parity space of each photon of an entangled pair and projective measurements onto a basis of even--odd functions. A Bell-operator value of 2.389 +- 0.016 is recorded, a violation of the inequality by more than 24 standard deviations.Comment: 10 pages, 3 figures, 1 Tabl

Cerebrovascular segmentation from MRA images

There is provided a method of processing a cerebrovascular medical image, the method comprising receiving magnetic resonance angiography (MRA) image associated with a cerebrovascular tissue comprising blood vessels and brain tissues other than blood vessels; segmenting MRA image using a prior appearance model for generating first prior appearance features representing a first-order prior appearance model and second appearance features representing a second-order prior appearance model of the cerebrovascular tissue, wherein current appearance model comprises a 3D Markov-Gibbs Random Field (MGRF) having a 2D rotational and translational symmetry such that MGRF model is 2D rotation and translation invariant; segmenting MRA image using current appearance model for generating current appearance features distinguishing blood vessels from other brain tissues; adjusting MRA image using first and second prior appearance features and current appearance futures; and generating an enhanced MRA image based on said adjustment. There is also provided a system for doing the same. Application US16/159,790 events 2018-10-15 Application filed by Zayed University 2018-10-15 Priority to US16/159,790 2018-10-15 Assigned to Zayed University 2020-04-16 Publication of US20200116808A1 2020-09-08 Application granted 2020-09-08 Publication of US10768259B2 Status Active 2039-03-02 Adjusted expiratio