scholarly journals Estudio de la evolución de flujos termocapilares inducidos con un laser IR en películas delgadas de agua para la manipulación de micro-objetos

2018 ◽  
pp. 12-19
Keyword(s):  
High Speed ◽  
Hot Spot ◽  
Research Work ◽  
Radial Distance ◽  
Thermocapillary Flows ◽  
Air Interface ◽  
Multiphysics Simulations ◽  
Evolution Study ◽  
Small Temperature Gradient ◽  
Liquid Depth

Estudio de la evolución de flujos termocapilares inducidos con un laser IR en películas delgadas de agua para la manipulación de micro-objetos    Evolution study of laser-induced thermocapillary flows for manipulation of micro-objects Johan E. Quispe y Emir Vela Departamento de Ingeniería Mecánica, Universidad de Ingeniería y tecnología - UTEC, Jr. Medrano Silva esquina con Av. Miguel Grau, Barranco DOI: https://doi.org/10.33017/RevECIPeru2015.0002/ Resumen En la actualidad, la micromanipulación ha adquirido un papel importante en el ensamblaje de microcomponentes electromecánicos, ya que hace posible manipular objetos a escala micrométrica de diferentes propiedades y formas geométricas para posteriormente realizar un ensamblado y así crear sistemas cada vez más multifuncionales. Igualmente, el campo de la medicina ha alcanzado grandes avances ya que la micromanipulación nos permite manipular células, moléculas y  bio-partículas en general, para realizar estudios más profundos en lo que respecta al comportamiento de éstas. Así, se requiere de un método de micromanipulación que sea capaz de desplazar micro-objetos biológicos como componentes de una manera rápida, precisa y múltiple que permita un estudio o producción a gran escala. Los métodos preferidos a la escala micrométrica son los métodos de manipulación sin contacto, ya que éstos permiten la manipulación sin dañar y contaminar las muestras u objetos. Dentro de éstos, la utilización de microfluidos para desplazar objetos es de gran interés en la comunidad científica ya que los fluidos permiten arrastrar a los objetos según la dirección y velocidad del fluido, lo que produce una fuerza que desplaza a los micro-objetos. En este trabajo de investigación se presenta un estudio, a través de simulaciones, de la generación de flujos termocapilares en películas delgadas de un líquido como método de manipulación sin contacto. Este método se está volviendo una opción viable para desplazar objetos a esta escala debido a su alta dinámica que permite desplazar objetos a gran velocidad, y además utilizando un bajo consumo de energía para su generación. Este método consiste en establecer un pequeño gradiente de temperatura en la interface líquido-aire de una película delgada, el cual genera  flujos toroidales,  centrados en el foco caliente, que hacen posible el desplazamiento  de los objetos en el interior del fluido, a través de una fuerza de arrastre que se establece. Este estudio nos permitió comprender cómo es la evolución temporal del flujo y cómo poder generarlos de manera controlada para lograr estrategias de manipulación eficientes y precisas. Se obtuvieron valores de velocidad del flujo del orden de  para un haz laser infrarojo que genera aproximadamente 80 mW sobre la muestra.  Además, existe una distancia radial con respecto al foco caliente donde sería más conveniente ubicar los objetos para manipularlos debido al perfil de velocidades que se establecen. También se demostró a través de las simulaciones que es posible establecer un tamaño de espesor de fluido para manipular objetos de un determinado tamaño. Descriptores: micromanipulación, flujo termocapilar, tensión superficial Abstract Nowadays, micromanipulation has an important role for assembly of micro-electromechanical components, because it enables to assemble very small components with different material properties and geometrical shapes in order to create complex multifunctional systems. Also, micromanipulation has contributed significantly in the field of medicine enabling manipulation of cells, molecules and bio-particles to study their behavior. Thus, a micromanipulation method that could move biological objects and microcomponents in an accurate, fast and multiple manner is needed. The preferred methods in the microscale are non-contact methods because they allow manipulating objects without damage or contamination. In this scope, microflows are very good candidates to drag micro-objects according to the flows direction and velocity, producing a drag force over the objects. In this research work, a study, through multiphysics simulations, on the thermocapillary flows generation within thin liquid layers is presented as a non-contact manipulation method. The high flows dynamics can move objects at high speed. This method consists of imaparting a very small temperature gradient at the liquid-air interface of a thin liquid layer, thus generating toroidal-shaped flows centered at the hot spot. So the objects inside the flows are dragged. This study allowed us to understand the temporal evolution of flows and how they could be generated in a controlled manner. Besides, it exists a radial distance with respect to the hot spot where is most suitable to place the objects to manipulate them at high speed due to the velocity profile. Flows speeds in the order of  were obtained using an infrared laser of about 80 mW. Simulations results showed that it is possible to establish a liquid depth in order to manipulate objects with specific sizes. As a result, manipulation strategies are being carried out to accurately move objects at high speeds. Keywords: micromanipulation, thermocapillary flows, surface tension.

Advances of Radio Interface in WCDMA Systems

2009 ◽  
pp. 9-14
Author(s):  
Ju Wang ◽  
Jonathan C.L. Liu
Keyword(s):  
High Speed ◽  
Hot Spot ◽  
Data Rate ◽  
Multimedia Data ◽  
Handheld Devices ◽  
Cdma System ◽  
Data Services ◽  
Radio Interface ◽  
High Data ◽  
Air Interface

Recent years have witnessed the rapid progress in handheld devices. This has resulted in a growing number of mobile phones or PDAs that have a built-in camera to record still pictures or live videos. Encouraged by the success of second generation cellular wireless networks, researchers are now pushing the 3G standard to support a seamless integration of multimedia data services. One of the main products is WCDMA (Holma & Toskala, 2001), short for wideband code division multiple access. WCDMA networks have 80 million subscribers in 46 countries at the time of this writing. WCDMA can be viewed as a successor of the 2G CDMA system. In fact, many WCDMA technologies can be traced back to the 2G CDMA system. However, WCDMA air interface is specifically designed with envision to support real time multimedia services. To name some highlights, WCDMA: • Supports both packet-switched and circuitswitched data services. Mobile best-effort data services, such as Web surfing and file downloads, are available through packet service. • Has more bandwidth allocated for downlink and uplink than the 2G systems. It uses a 5 MHz wide radio signal and a chip rate of 3.84 mcps, which is about three times higher than CDMA2000. • Support a downlink data rate of 384 kbps for wide area coverage and up to 2 Mbps for hot-spot areas, which is sufficient for most existing packet-data applications. WCDMA Release 5 (Erricson, 2004) adopts HSDPA (High-speed downlink packet access), which increases peak data rates to 14 Mbps in the downlink. To achieve high data rate, WCDMA uses several new radio interface technologies, including (1) shared channel transmission, (2) higher-order modulation, (3) fast link adaptation, (4) fast scheduling, and (5) hybrid automatic-repeat-request (HARQ). These technologies have been successfully used in the downlink HSDPA, and will be used in upcoming improved uplink radio interface in the future. The rest of this article will explain the key components of the radio interface in WCDMA.

scholarly journals Jet-Surface Interaction Test: Far-Field Noise Results

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Clifford A. Brown
Keyword(s):  
High Speed ◽  
Radial Distance ◽  
Jet Noise ◽  
Surface Interaction ◽  
Shielding Effect ◽  
Noise Prediction ◽  
Far Field ◽  
Wide Range ◽  
Field Noise ◽  
Surface Length

Many configurations proposed for the next generation of aircraft rely on the wing or other aircraft surfaces to shield the engine noise from the observers on the ground. However, the ability to predict the shielding effect and any new noise sources that arise from the high-speed jet flow interacting with a hard surface is currently limited. Furthermore, quality experimental data from jets with surfaces nearby suitable for developing and validating noise prediction methods are usually tied to a particular vehicle concept and, therefore, very complicated. The Jet-Surface Interaction Tests are intended to supply a high quality set of data covering a wide range of surface geometries and positions and jet flows to researchers developing aircraft noise prediction tools. The initial goal is to measure the noise of a jet near a simple planar surface while varying the surface length and location in order to: (1) validate noise prediction schemes when the surface is acting only as a jet noise shield and when the jet-surface interaction is creating additional noise, and (2) determine regions of interest for future, more detailed, tests. To meet these objectives, a flat plate was mounted on a two-axis traverse in two distinct configurations: (1) as a shield between the jet and the observer and (2) as a reflecting surface on the opposite side of the jet from the observer. The surface length was varied between 2 and 20 jet diameters downstream of the nozzle exit. Similarly, the radial distance from the jet centerline to the surface face was varied between 1 and 16 jet diameters. Far-field and phased array noise data were acquired at each combination of surface length and radial location using two nozzles operating at jet exit conditions across several flow regimes: subsonic cold, subsonic hot, underexpanded, ideally expanded, and overexpanded supersonic. The far-field noise results, discussed here, show where the jet noise is partially shielded by the surface and where jet-surface interaction noise dominates the low frequency spectrum as a surface extends downstream and approaches the jet plume.

Mechanical Analysis of Low and High Chromium Steels Used in Hot Strip Work Rolls

2018 ◽  
Vol 279 ◽  
pp. 3-9
Author(s):  
Fethi Benkhenafou ◽  
Ines Fernández Pariente ◽  
F.Javier Belzunce ◽  
Abdelkader Ziadi ◽  
Ming Quan Shi ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
High Speed ◽  
Volume Fraction ◽  
Research Work ◽  
High Speed Steel ◽  
Nodular Cast Iron ◽  
High Chromium ◽  
Eutectic Carbides ◽  
Hot Strip ◽  
Conventional Heat Treatment

Microstructure, hardness and fracture toughness of low and high chromium high speed steel used in hot strip mills and subjected to conventional heat treatment have been examined. The influence of tempering temperatures on the mechanical properties of these products, determined using tensile and fracture toughness tests, was studied in this research work. The developed microstructures have been characterized by XRD, optical microscopy and SEM examinations. Macrohardness and microhardness of the specimens have been evaluated by Vickers indentation technique. The fracture toughness of these products was investigated using the rupture weight on 3 points bending specimens. The plane strain fracture toughness KIc and the fracture strength were measured for each alloy. The shell is high harness high speed steels, and the core is nodular cast iron. It was found that most fracture occurred in the eutectic carbides formed by the high content alloy element, such as Mo,V,Cr, but that for the alloys with a reduced volume fraction of eutectic carbides, a small amount of crack propagation occurred in the austenitic dendrites.

scholarly journals Strategic Directions of Pedagogical Personnel Training for the System of Continuing Vocational Education

2019 ◽  
Vol 21 (6) ◽  
pp. 93-121 ◽  
Author(s):  
E. F. Zeer ◽  
V. S. Tretyakova ◽  
V. I. Miroshnichenko
Keyword(s):  
Vocational Education ◽  
Research Methods ◽  
Vocational Training ◽  
High Speed ◽  
Structural Changes ◽  
Research Work ◽  
Practical Significance ◽  
Inductive Method ◽  
Highly Qualified ◽  
Speed Training

. Introduction. Transition to a post-industrial socio-economic structure and information society caused education crisis, which is common for world space. Dynamic development of high technologies and rapid obsolescence of knowledge significantly reduced life cycle of professions and caused deep structural changes in the sphere of employment. The need of economics for workers with qualitatively new qualification characteristics - a flexible person with meta-professional competencies, capable to solve complex professional problems and ready for innovative activity not just for today, but with the future in mind - has necessitated a significant updating of the system of vocational training and its reorganisation facilitating the implementation of a formula “lifelong learning”. The solution of problems of education begins with qualitative training of teachers, since the qualities of future professionals - graduates of the educational organisation, primarily depend on the level of teachers’ competencies.The aim of the present article is to determine the strategic directions of innovative development of vocational education and preparation of highly qualified pedagogical personnel.Methodology and research methods. The hypothetico-inductive method, theoretic-methodological analysis and synthesis of the content of scientific literature were the major research methods. The research work was carried out on the basis of the principle of convergence, which determines cross-disciplinary and supra-professional communications, acts as a factor of design and a statement in professiology of a new phenomenon - transprofessionalism. The authors described the concept of transprofessionalism through the process- and project-based approaches.Results and scientific novelty. The developmental trends and directions of vocational education are considered. The principal defining factor of vocational education is close integration of all its processes and subsystems (prevocational training - secondary vocational education - higher education institutions - postgraduate training), which integrity is provided by the continuing and advanced education. The concept of transprofessionalism and convergence in multidisciplinary training of specialists is proved. The innovative educational programmes based on this concept are characterised. The logical-semantic model of a modern specialist is designed. This model can form an empirical basis to design vocational education platform, which integrates socio-humanistic, natural-science disciplines and related innovative technologies for teachers’ training in the system of continuing vocational education. Strategic directions for realisation of such preparation are formulated: transprofessionalism, cooperation / collaboration, advanced and “high-speed” training, digital transformation.Practical significance. The research materials can be useful for specialists in the field of vocational education, heads of the educational organisations in order to develop and make managerial decisions and to effectively organise the process of vocational training of pedagogical personnel.

scholarly journals A microarray gene expressions with classification using extreme learning machine

Genetika ◽  
2015 ◽  
Vol 47 (2) ◽  
pp. 523-534
Author(s):  
M. Yasodha ◽  
P. Ponmuthuramalingam
Keyword(s):  
Extreme Learning Machine ◽  
High Speed ◽  
Dna Microarrays ◽  
Research Work ◽  
The Body ◽  
Cancer Classification ◽  
Medical Sciences ◽  
Gene Expressions ◽  
Learning Machine ◽  
Elm Classifier

In the present scenario, one of the dangerous disease is cancer. It spreads through blood or lymph to other location of the body, it is a set of cells display uncontrolled growth, attack and destroy nearby tissues, and occasionally metastasis. In cancer diagnosis and molecular biology, a utilized effective tool is DNA microarrays. The dominance of this technique is recognized, so several open doubt arise regarding proper examination of microarray data. In the field of medical sciences, multicategory cancer classification plays very important role. The need for cancer classification has become essential because the number of cancer sufferers is increasing. In this research work, to overcome problems of multicategory cancer classification an improved Extreme Learning Machine (ELM) classifier is used. It rectify problems faced by iterative learning methods such as local minima, improper learning rate and over fitting and the training completes with high speed.

Appraisal of OFDM for multi-carrier, high-speed data rate wireless communication networks

2019 ◽  
Author(s):  
Muhammad Bello Abdullahi
Keyword(s):  
Wireless Communication ◽  
Communication Networks ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Research Work ◽  
Wireless Systems ◽  
Data Rate ◽  
High Quality Research ◽  
Global Issues ◽  
High Speed Data

Orthogonal Frequency Division Multiplexing (OFDM) is used to achieve multi-carrier signals and high- Speed data rate in free space. OFDM-based systems operate in the hostile multipath radio environment, which allows efficient sharing of limited resources. This research work was designed, developed and simulated an OFDM System using the basic blocks of Simulink in MATLAB/Simulink software, to support multi-carrier, high-speed data rates. This was achieved in backing of collection and review of high-quality research papers, which reported the latest research developments in OFDM communications networks, and its applications in future wireless systems. The research work significantly increases the speed of data rate signals, and many critical problems associated with the applications of OFDM technologies in future wireless systems are still looking for efficient solutions. This would overcome the global issues and challenges facing the limited bandwidth in wireless communication network.

Novel Taxonomy to Select Fog Products and Challenges Faced in Fog Environments

2021 ◽  
pp. 2558-2571
Author(s):  
Akashdeep Bhardwaj
Keyword(s):  
Cloud Computing ◽  
Distributed Computing ◽  
High Speed ◽  
Low Cost ◽  
Fog Computing ◽  
Research Work ◽  
Cloud Services ◽  
Smart Devices ◽  
Viable Solution ◽  
Last Mile

This article describes how the rise of fog computing to improve cloud computing performance and the acceptance of smart devices is slowly but surely changing our future and shaping the computing environment around us. IoT integrated with advances in low cost computing, storage and power, along with high speed networks and big data, supports distributed computing. However, much like cloud computing, which are under constant security attacks and issues, distributed computing also faces similar challenges and security threats. This can be mitigated to a great extent using fog computing, which extends the limits of Cloud services to the last mile edge near to the nodes and networks, thereby increasing the performance and security levels. Fog computing also helps increase the reach and comes across as a viable solution for distributed computing. This article presents a review of the academic literature research work on the Fog Computing. The authors discuss the challenges in Fog environment and propose a new taxonomy.

scholarly journals AN INTERVIEW WITH ASSAR LINDBECK

2005 ◽  
Vol 10 (1) ◽  
pp. 101-130 ◽  
Author(s):  
Thorvaldur Gylfason
Keyword(s):  
High Speed ◽  
Empirical Studies ◽  
Research Work ◽  
Economic Thought ◽  
Daily Newspaper ◽  
Scientific Publications ◽  
Social Democrats ◽  
Guiding Principle ◽  
History Of ◽  
The Many

Sweden has a long and distinguished tradition in economics, beginning with Knut Wicksell and continuing with Gustav Cassel, Eli Heckscher, Erik Lindahl, Gunnar Myrdal, Bertil Ohlin, and Erik Lundberg, all of whom are now gone. Yet, for several of these men, economics was not enough: Wicksell spoke out on moral issues and served time in jail, and Myrdal was for many years a high official at the United Nations and, briefly, a cabinet minister, as was Ohlin, who made his mark at home primarily as leader of the opposition in a country governed mostly by Social Democrats, serving in parliament for 32 years. For Assar Lindbeck, however, economics has been broad enough: he has devoted a long and distinguished career to economics, and to economics alone, with unfailing enthusiasm and energy over half a century. Not that he was not wanted elsewhere: over the years, he has declined challenging job offers from an international organization and a Swedish daily newspaper, to name but two examples, as well as from universities outside Sweden. Assar has managed to harness his varied and wide-ranging talents within the many mansions of economics. He is one of the most versatile economists of his generation. Indeed, he is one of the few who, for clarity, need to divide their bibliography into categories by subject: Macroeconomics and monetary economics, Public economics, Labor economics, International economics, Economic systems and economic structures, Methodology and history of economic thought, and Swedish economy. His work on these different subjects has ranged from pure theory to applied policy-oriented and empirical studies. In addition to the numerous scientific publications listed at the end of this interview, his bibliography includes nearly 200 articles for magazines and newspapers. His ivory tower has always been equipped with a high-speed elevator. But, as he points out in the conversation to follow, all his research work, as well as his journalism, is driven by an overarching interest in bettering economic policy and organization—in other words, boosting economic and social efficiency for the purpose of lifting ordinary people's standard of life. This has been, and remains, a guiding principle—a Leitmotiv, if you prefer—from which he has never swerved. Assar Lindbeck is a towering figure in Swedish economics and in Swedish national life.

scholarly journals Substorm observations in the early morning sector with Equator-S and Geotail

1999 ◽  
Vol 17 (12) ◽  
pp. 1602-1610 ◽  
Author(s):  
R. Nakamura ◽  
G. Haerendel ◽  
W. Baumjohann ◽  
A. Vaivads ◽  
H. Kucharek ◽  
...  
Keyword(s):  
Plasma Sheet ◽  
High Speed ◽  
Radial Distance ◽  
Early Morning ◽  
Field Configuration ◽  
Morning Sector ◽  
Magnetospheric Configuration And Dynamics ◽  
Abstract Data ◽  
Shear Structure ◽  
Poleward Expansion

Abstract. Data from Equator-S and Geotail are used to study the dynamics of the plasma sheet observed during a substorm with multiple intensifications on 25 April 1998, when both spacecraft were located in the early morning sector (03–04 MLT) at a radial distance of 10–11 RE. In association with the onset of a poleward expansion of the aurora and the westward electrojet in the premidnight and midnight sector, both satellites in the morning sector observed plasma sheet thinning and changes toward a more tail-like field configuration. During the subsequent poleward expansion in a wider local time sector (20–04 MLT), on the other hand, the magnetic field configuration at both satellites changed into a more dipolar configuration and both satellites encountered again the hot plasma sheet. High-speed plasma flows with velocities of up to 600 km/s and lasting 2–5 min were observed in the plasma sheet and near its boundary during this plasma sheet expansion. These high-speed flows included significant dawn-dusk flows and had a shear structure. They may have been produced by an induced electric field at the local dipolarization region and/or by an enhanced pressure gradient associated with the injection in the midnight plasma sheet.Key words. Magnetospheric physics (magnetospheric configuration and dynamics; plasma sheet; storms and substorms)

230 GENERATION OF PUTATIVE RABBIT EMBRYONIC STEM CELLS

2007 ◽  
Vol 19 (1) ◽  
pp. 231
Author(s):  
S. Wang ◽  
X. Tang ◽  
Y. Niu ◽  
H. Chen ◽  
T. Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
High Speed ◽  
Es Cells ◽  
Research Work ◽  
Embryonic Stem ◽  
Morphological Characteristics ◽  
Mouse Escs

The rabbit, as a laboratory animal model, has several advantages in the study of human physiological disorders. In this study, stable putative pluripotent rabbit embryonic stem cells (rESCs) were derived from in vivo-fertilized and in vitro-cultured blastocysts. The rabbit ICMs were obtained by 0.05% trypsin–0.008% EDTA treatment and mechanical separation; the ES-like cell colonies seen several days later. ICM-derived outgrowths which were treated with 5 mg/mL-1 dispase, followed by 0.05% trypsin–0.008% EDTA, were mechanically disaggregated into small clumps and reseeded on MEFs. The putative ES cell lines maintained expression of pluripotent cells markers and normal XY karyotype for long periods of culture (>1 month). The putative rESCs expressed alkaline phosphatase, transcription factor Oct-4, stage-specific embryonic antigens (SSEA-1, SSEA-3, and SSEA-4), and tumor-related antigens (TRA-1-60 and TRA-1-81). The morphological characteristics of the putative ESCs are closer to those of human ESCs; their high speed of proliferation, however, is closer to that of mouse ESCs. Putative rabbit ESCs were induced to differentiate into many cell types including trophoblast cells, similar to primate ESCs, in vitro, and formed teratomas with derivatives of the 3 major germ layers in vivo when injected into SCID mice. Using RT-PCR measurement, but with some differences in ligands and inhibitors, and comparing with human and mouse ESCs, the putative rabbit ESCs expressed similar genes related to pluripotency (Oct-4, Nanog, SOX2, and UTF-1) and similar genes of FGF, WNT, and TGF signaling pathways related to the proliferation and self-renewal. Our further research work showed that TGF beta and FGF pathways cooperate to maintain pluripotency of rabbit ESCs similar to those of human ES cells.

Sign in / Sign up

Export Citation Format

Share Document