694 research outputs found
Observing angular deviations in light beam reflection via weak measurements
An optical analog of the quantum weak measurement scheme proved to be very
useful for the observation of optical beam shifts. Here we adapt the weak value
amplification method for the observation of the angular Goos-Hanchen shift. We
observe this effect in the case of external air-dielectric reflection, the more
fundamental case in which it occurs.We show that weak measurements allow for a
faithful amplification of the effect at any angle of incidence, even at the
Brewster angle of incidence
Droplet breakup driven by shear thinning solutions in a microfluidic T-Junction
Droplet-based microfluidics turned out to be an efficient and adjustable
platform for digital analysis, encapsulation of cells, drug formulation, and
polymerase chain reaction. Typically, for most biomedical applications, the
handling of complex, non-Newtonian fluids is involved, e.g. synovial and
salivary fluids, collagen, and gel scaffolds. In this study we investigate the
problem of droplet formation occurring in a microfluidic T-shaped junction,
when the continuous phase is made of shear thinning liquids. At first, we
review in detail the breakup process providing extensive, side-by-side
comparisons between Newtonian and non-Newtonian liquids over unexplored ranges
of flow conditions and viscous responses. The non-Newtonian liquid carrying the
droplets is made of Xanthan solutions, a stiff rod-like polysaccharide
displaying a marked shear thinning rheology. By defining an effective Capillary
number, a simple yet effective methodology is used to account for the
shear-dependent viscous response occurring at the breakup. The droplet size can
be predicted over a wide range of flow conditions simply by knowing the
rheology of the bulk continuous phase. Experimental results are complemented
with numerical simulations of purely shear thinning fluids using Lattice
Boltzmann models. The good agreement between the experimental and numerical
data confirm the validity of the proposed rescaling with the effective
Capillary number.Comment: Manuscript: 11 pages 5 figures, 65 References. Textual Supplemental
Material: 6 pages 3 figure. Video Supplemental Materials: 2 movie
Drop mobility on chemically heterogeneous and lubricant-impregnated surfaces
Controlling the motion of liquid drops in contact with a solid surface has broad technological implications in many different areas ranging from textiles to microfluidics and heat exchangers. The wettability of a surface is determined by specifying the apparent contact angle and contact angle hysteresis (CAH) that depend on the surface chemistry and morphology. The presence of chemical inhomogeneity and morphological disorder usually increases CAH. A liquid substrate, whose surface is atomically flat and homogenous, is then expected to exhibit a very low CAH. Low CAH determines high drop mobility, while high CAH favours drop pinning. Very slippery surfaces with exceptional omniphobicity are obtained by impregnating a textured solid with a lubricant. To guide and control the motion of drops, the solid surface can be decorated with suitable chemical patterns. In this review, we briefly outline the main results obtained in the past few years to passively control drop motion and produce robust omniphobic surfaces, highlighting some of the most promising applications of these novel functional surfaces
Analysis of Outsourcing Activities in the Banking Industry in Nigeria: The Rationale and Perceived Benefits
This study examined rationale and benefits for outsourcing in Nigerian banking industry. The study utilized primary data which were collected through questionnaire and key informant interviews. The data collected were analysed using descriptive and inferential statistical techniques. The paper found that security, cleaning, recruitment, training, human resources and ATM are the most outsourced services in the Nigerian Banking Industry. The study however revealed that, technical convenience and efficiency, increased productivity/performance, the need to focus on core activities, Improvement of service delivery and quality, as well as to meet changing customers’ needs are the major rationale for outsourcing in Nigerian banking industry. In addition, the study concluded that increased flexibility, growth of banks and increased services are the major benefits of outsourcing in the Nigerian Banking Industry. The study however concluded that, poor suppliers’ problem, reputation damage and poor expertise delivery are the major risk which the banking industry are confronted with whenever they outsource their activities. Keywords: Outsourcing benefits, strategic management, Nigerian banks, DOI: 10.7176/EJBM/12-23-04 Publication date:August 31st 202
Securing an Information Systems from Threats: A Critical Review
The technology behind information systems in today’s world has been embedded in nearly every aspect of our lives. Thus, the idea of securing our information systems and/or computer networks has become very paramount. Owing to the significance of computer networks in transporting the information and knowledge generated by the increased diversity and sophistication of computational machinery, it would be very imperative to engage the services of network security professionals to manage the resources that are passed through the various terminals (end points) of the these network, so as to achieve a maximum reliability of the information passed, making sure that this is achieved without creating a discrepancy between the security and usability of such network. This paper examines the various techniques involved in securely maintaining the safe states of an active computer network, its resources and the information it carries. We examined techniques of compromising an information system by breaking into the system without authorised access (Hacking), we also looked at the various phases of digital analysis of an already compromised system, and then we investigated the tools and techniques for digitally analysing a compromised system in other to bring it back to a safe stat
Abóbora-gila (cucurbita ficifolia), uma hortaliça pouco convencional cultivada no Rio Grande do Sul.
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