2,203 research outputs found
Casimir interaction at liquid nitrogen temperature: Comparison between experiment and theory
We have measured the normalized gradient of the Casimir force between
Au-coated surfaces of the sphere and the plate and equivalent Casimir pressure
between two parallel Au plates at T=77K. These measurements have been performed
by means of dynamic force microscope adapted for operating at low temperatures
in the frequency shift technique. It was shown that the measurement results at
T=77K are in a very good agreement with those at T=300K and with computations
at T=77K using both theoretical approaches to the thermal Casimir force
proposed in the literature. No thermal effect in the Casimir pressure was
observed in the limit of experimental errors with the increase of temperature
from T=77K to T=300K. Taking this into account, we have discussed the possible
role of patch potentials in the comparison between measured and calculated
Casimir pressures.Comment: 18 pages, 8 figures, to appear in Phys. Rev.
Logistics service providers and Industry 4.0: A systematic literature review
Background: Industry 4.0 is one of the topics related to manufacturing, supply chain and logistics that has received great interest from the academic community, organizations and governments in the last decade. Problem statement: Several published articles discuss and seek to conceptualize what the fourth industrial revolution is, but no research relates industry 4.0 in the context of logistics service providers (LSPs) in a clear and structured way. Objectives: This study aims to fill this research gap, proposing a conceptual framework and addressing the challenges, barriers and organizational dimensions that need adaptation to insert LSPs in the new Industry 4.0 environment. Methods: This theoretical and conceptual study uses the Systematic Literature Review (SLR) as a research method to understand the Industry 4.0 phenomenon in the context of LSPs. Contributions: The relevant constructs identified in this research will help professionals and organizations that provide logistics services to develop strategies and encourage new research in the 15 field of Industry 4.0 from the perspective of LSPs. Results: In addition, this research identified and generally consolidated six dimensions, as a result of this innovative study a conceptual framework is presented
The replicative lifespan-extending deletion of SGF73 results in altered ribosomal gene expression in yeast.
Sgf73, a core component of SAGA, is the yeast orthologue of ataxin-7, which undergoes CAG-polyglutamine repeat expansion leading to the human neurodegenerative disease spinocerebellar ataxia type 7 (SCA7). Deletion of SGF73 dramatically extends replicative lifespan (RLS) in yeast. To further define the basis for Sgf73-mediated RLS extension, we performed ChIP-Seq, identified 388 unique genomic regions occupied by Sgf73, and noted enrichment in promoters of ribosomal protein (RP)-encoding genes. Of 388 Sgf73 binding sites, 33 correspond to 5' regions of genes implicated in RLS extension, including 20 genes encoding RPs. Furthermore, half of Sgf73-occupied, RLS-linked RP genes displayed significantly reduced expression in sgf73Δ mutants, and double null strains lacking SGF73 and a Sgf73-regulated, RLS-linked RP gene exhibited no further increase in replicative lifespan. We also found that sgf73Δ mutants display altered acetylation of Ifh1, an important regulator of RP gene transcription. These findings implicate altered ribosomal protein expression in sgf73Δ yeast RLS and highlight altered acetylation as a pathway of relevance for SCA7 neurodegeneration
Variable cavity volume tooling for high-performance resin infusion moulding
This article describes the research carried out by Warwick under the BAE Systems/EPSRC programme ‘Flapless Aerial Vehicles Integrated Interdisciplinary Research – FLAVIIR’. Warwick's aim in FLAVIIR was to develop low-cost innovative tooling technologies to enable the affordable manufacture of complex composite aerospace structures and to help realize the aim of the Grand Challenge of maintenance-free, low-cost unmanned aerial vehicle manufacture. This article focuses on the evaluation of a novel tooling process (variable cavity tooling) to enable the complete infusion of resin throughout non-crimp fabric within a mould cavity under low (0.1 MPa) injection pressure. The contribution of the primary processing parameters to the mechanical properties of a carbon composite component (bulk-head lug section), and the interactions between parameters, was determined. The initial mould gap (di) was identified as having the most significant effect on all measured mechanical properties, but complex interactions between di, n (number of fabric layers), and vc (mould closure rate) were observed. The process capability was low due to the manual processing, but was improved through process optimization, and delivered properties comparable to high-pressure resin transfer moulding
Experimental procedures for precision measurements of the Casimir force with an Atomic Force Microscope
Experimental methods and procedures required for precision measurements of
the Casimir force are presented. In particular, the best practices for
obtaining stable cantilevers, calibration of the cantilever, correction of
thermal and mechanical drift, measuring the contact separation, sphere radius
and the roughness are discussed.Comment: 14 pages, 7 figure
Altruism and social integration
We develop a two-stage experimental protocol by which i) we elicit the social network within a group of undergraduate students and ii) we measure their altruistic attitudes by way of a standard Dictator game. We observe that more socially integrated subjects are also more altruistic, as betweenness centrality and reciprocal degree are positively correlated with the level of giving, even after controlling for the effect of social distance, which has been shown to affect giving. Our findings suggest that social distance and network position are complementary determinants of altruistic behavior
Gradient of the Casimir force between Au surfaces of a sphere and a plate measured using atomic force microscope in a frequency shift technique
We present measurement results for the gradient of the Casimir force between
an Au-coated sphere and an Au-coated plate obtained by means of an atomic force
microscope operated in a frequency shift technique. This experiment was
performed at a pressure of 3x10^{-8} Torr with hollow glass sphere of 41.3 mcm
radius. Special attention is paid to electrostatic calibrations including the
problem of electrostatic patches. All calibration parameters are shown to be
separation-independent after the corrections for mechanical drift are included.
The gradient of the Casimir force was measured in two ways with applied
compensating voltage to the plate and with different applied voltages and
subsequent subtraction of electric forces. The obtained mean gradients are
shown to be in mutual agreement and in agreement with previous experiments
performed using a micromachined oscillator. The obtained data are compared with
theoretical predictions of the Lifshitz theory including corrections beyond the
proximity force approximation. An independent comparison with no fitting
parameters demonstrated that the Drude model approach is excluded by the data
at a 67% confidence level over the separation region from 235 to 420 nm. The
theoretical approach using the generalized plasma-like model is shown to be
consistent with the data over the entire measurement range. Corrections due to
the nonlinearity of oscillator are calculated and the application region of the
linear regime is determined. A conclusion is made that the results of several
performed experiments call for a thorough analysis of the basics of the theory
of dispersion forces.Comment: 35 pages, 14 figures, 1 table; to appear in Phys. Rev.
Green Lean Six Sigma for sustainability improvement: a systematic review and future research agenda
Design/ Methodology/ Approach: To do a systematic analysis of the literature, a systematic literature review methodology has been used in this research work. 140 articles from the
reputed databases were identified to explore hidden aspects of GLSS. Exploration of articles in different continents, year-wise, approach-wise, and journal-wise, were also done to find the execution status of GLSS.
Purpose: The main purpose of this article is to explore different aspects of the Green Lean Six Sigma approach, application status, and potential benefits from a comprehensive review of the literature and provides an avenue for future research work. The study also provides a
conceptual framework for GLSS.
Findings: The study depicts that GLSS implementation is increasing year by year, and it leads to considerable improvement in all dimensions of sustainability. Enablers, barriers, tools, and potential benefits that foster the execution of GLSS in industrial organizations are also identified based on a systematic review of the literature.
Originality: The study's uniqueness lies in that study is the first of its kind that depicts the execution status of GLSS, and its different facets, explores different available frameworks and provides avenues for potential research in this area for potential researchers and practitioners
Trace Mineral Status of Beef Cattle Grazing Semiarid Rangelands of North Mexico
Trace mineral concentrations of soil, forage and serum of range cattle of the northeast Mexico state of Nuevo Leon were determined in both wet and dry seasons of 1992. For each season, collections were made at twenty-four ranches within eleven counties of three regions. A total of 220 soil, 680 forage and 220 blood samples were collected and analyzed. No differences (P\u3c0.05) between regions were obtained for Zinc (28.0 to 34.9 ppm) or Copper (4.4 to 5.4 ppm). Molybdenum concentrations were greater in the northern (2.1 ppm) than in the central (1.6 ppm) or southern (1.5 ppm) regions. Considering the critical levels in forages for Zinc (30 ppm) and Copper (10 ppm) reported by the National Research Council (1984), Zinc concentrations may be marginally deficient, whereas Copper concentrations were deficient in all three regions, in both seasons, and in grasses and woody species
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