1,793 research outputs found
Growth and Characterization of CuO Nanostructures on Si for the Fabrication of CuO/p-Si Schottky Diodes
CuO interlayers in the CuO/p-Si Schottky diodes were fabricated by using CBD and sol-gel methods. Deposited CuO layers were characterized by SEM and XRD techniques. From the SEM images, it was seen that the film grown by CBD method is denser than the film grown by sol-gel method. This result is compatible with XRD results which show that the crystallization in CBD method is higher than it is in sol-gel method. For the electrical investigations, current-voltage characteristics of the diodes have been studied at room temperature. Conventional I-V and Norde’s methods were used in order to determine the ideality factor, barrier height, and series resistance values. It was seen that the morphological and structural analysis are compatible with the results of electrical investigations
A geochemical equilibrium modeling approach to assessing soil acidification impacts due to depositions of industrial air emissions
Soil acidification impacts arising from depositions of industrial air emissions may become a serious environmental concern. Currently, in the literature quantitative mechanistic modeling and the experimental acid neutralizing capacity (ANC) approach and a qualitative evaluation approach classifying soils into various levels of sensitivity to acid additions have been reported to assess the long-term soil acidification impacts due to industrial air emissions. Another alternative quantitative approach proposed by this study is the geochemical modeling approach that can be used to similate an ANC curve based on relevant soil chemistry data by calculating the equilibrium distributions of chemical species in the soil solution according to the specified geochemical processes. The purpose of this syudy was essentially to illustrate the potential applications and practical utility of the proposed geochemical modeling approach to assessing soil acidification impacts due to industrial air emissions. The application of the geochemical modeling approach was illustrated by comparisons of the experimental and simulated ANC curves for a calcareous and a noncalcareous soil representing insensitive and sensitive soil cases, respectively. Results obtained from these comparisons reveal that, in terms of producing the ANC curve for the soil solution, the geochemical modeling approach seems to perform well and produce more reliable results for calcareous soil than for noncalcareous soil. However, the approach can also be used for noncalcareous soils when the air emission rates are low and may need further testing with additional measured data for a wide range of soils other than those presented in this study
Hydrodynamic Effects of Debris Blockage and Scour on Masonry Bridges: Towards Experimental Modelling
This is the author accepted manuscript. The final version is available from CRC Press via the DOI in this record8th International Conference on Scour and Erosion, 12-15 September 2016, Oxford, UKThis paper describes the preliminary stage of an ongoing project investigating the hydrodynamic effects of debris blockage at masonry bridges. Debris blockage is cited as one of the primary causes of bridge failures in the UK and around the world. Masonry bridges, many of which are valuable historical assets, are particularly vulnerable to debris blockage due to their short spans and low clearance. This paper presents work done as part of the first phase of the project involving experimental research to understand the scientific relationships between debris characteristics and flow conditions. The study, being carried out at Centre for Water Systems at University of Exeter, utilizes a 0.6m-wide and 10m-long flume to run hydraulic experiments in order to characterize the impact of debris blockage on flow hydrodynamics, scour, and hydrodynamic pressures and forces at masonry bridges. This paper outlines the design of the experimental setup and the reasoning behind the choices for preliminary experimental parameters. The experiments are to include testing of bridge models and various 3D-printed debris shapes under realistic flow conditions. Geometry of the bridge and debris mod-els are kept approximately similar to prototype conditions, with hydraulic conditions of the experiments de-signed to the degree that experimental constraints allow based on Froude similarity. Velocities, scour and hy-drodynamic pressures are measured using an Acoustic Doppler Velocimeter, echo-sounding concept and pres-sure sensors, respectively. Preliminary results indicate that the designed experiments have the potential to en-hance our understanding of the hydrodynamic effects of debris blockage.The research presented in this paper was supported by funding from the UK’s Engineering and Physical Sciences Research Council (EPSRC) under grant EP/M017354/1. The authors are grateful to project partners for their support, particularly Devon County Council and Network Rail for providing useful prototype data
DIAGNOSIS OF PERSISTENT BVD IN ONE DAY OLD AND OLDER THAN 30 DAYS CALVES WITH RAPID KIT TESTS
Bovine Viral Diarrhoea (BVD) is an important disease of cattle which causes alimentary, respiratory and reproductive disorders and serious economic losses. Today, eradication of disease is compulsory for the increase of dairies and achieving more healthier herds. In cattle, if the calves are infected with BVD from the uterus in the first trimester of pregnancy, they are born persistent infected (PI) antigen(+). The PI calves are smaller or normal in apperance than normal calves. Persistent infected (PI) calves spread the virus throughout their lives and infect their surroundings. BVD causes early embrionic death, calves born with anomalies and immunosuppression in infected animals. In this study 200 calves between 1–30 days old from Burdur province are screened with BVD rapid test kit. In the screening, 13 calves (6.5%) are found BVDV ag(+). The gender of PI calves are found 4% female (8/200) and 2.5% male (5/200). In the 5% of PI calves (10/200), respiratory and alimentary problems were clinically seen. The antigen(+) animals are put out of the herd and vaccination protocols are recommended. In this study, diagnosing the disease can be made rapidly by both clinicians and farmers, also putting the virus spreading persistent calves out of herd without losing time and a successful struggle can be made against BVD, are shown
Laccase activity from the fungus trametes hirsuta using an air-lift bioreactor
Aim: To produce high laccase activities from the white-rot fungus Trametes hirsuta in an in-house air-lift bioreactor (ALB).
Methods and Results: Trametes hirsuta was grown in a 6-l ALB. A fed-batch strategy with glycerol as an addition resulted in maximum laccase activity of 19 400 U l)1, which was the highest reported from the fungus.
Conclusion: The ALB configuration with additional glycerol resulted in high
laccase activities.
Significance and Impact of the Study: This study provides useful information on how to produce high concentrations of laccase.Fundação para a Ciência e a Tecnologia (FCT)University of Vigo (SpainDepartment of Biological Engineering of the University of Minho, Portuga
Prediction of flow around a sharp-nosed bridge pier: Influence of the Froude number and free surface variation on the flow field (article)
This is the final version. Available on open access from Taylor & Francis via the DOI in this recordThe dataset associated with this article is located in ORE at: https://doi.org/10.24378/exe.1503Author accepted manuscript replaced with published version by Caroline Huxtable on 2019-10-11This study investigates the influence of free surface variation on the velocity field using numerical simulations of flow around a
sharp-nosed pier that is representative of a typical masonry bridge pier. This study evaluates the assumption that free surface effects
are negligible at small Froude numbers by comparing the change in flow field predictions due to the use of a free surface model (i.e.
multi-phase simulation with a Volume of Fluid (VOF) model in place of a rigid-lid approximation (i.e. single phase simulation).
Results show that simulations using the VOF model are in better agreement with experimental data than those using the rigid-lid
approximation. Importantly, results show that even though the change in free surface height near the pier is small comparative to
the approach flow, it still has a significant effect on velocities in front of the pier and in the wake region, and that too at low Froude
numbers.Engineering and Physical Sciences Research Council (EPSRC
Investigation of salmonella spp. and listeria monocytogenes in seafood by cultural methods and pcr
Scour and hydrodynamic effects of debris blockage at masonry bridges: insights from experimental and numerical modelling
The final version is available from IAHR via the URL in this record.This paper describes preliminary results of a project investigating the scour and hydrodynamic effects of debris blockage at masonry bridges. Debris blockage, which is often cited as one of the primary causes of bridge failures in the UK and around the world, results in a larger obstruction to the flow leading to increased flow velocities, scour and hydrodynamic forces, compared to the conditions without debris. This, in turn, can affect the structural stability of bridges, for example, by undermining their foundations. Masonry bridges, many of which are valuable historical assets, are particularly vulnerable to debris blockage due to their short spans and low clearance. The reported study, being undertaken at the Centre for Water Systems at the University of Exeter, has two main phases: (i) laboratory experiments and (ii) CFD simulations. In the first phase, a 0.6m-wide and 10m-long flume is utilized to study the flow hydrodynamics and scour associated with pier/bridge models in several reference scenarios. The geometry of the pier/bridge and debris models are kept approximately similar to prototype conditions, with hydraulic conditions of the experiments designed to the degree that laboratory constraints allow to maintain Froude similarity. Velocities and scour are measured via an acoustic Doppler velocimeter and echo-sounding concept. Experimental results are used to calibrate and validate CFD models which can later enable simulation of more complicated scenarios. This paper will report these preliminary results from both experimental and CFD phases. Preliminary experimental results highlight the significance of debris existence in enhancing scour due to increasing flow downward velocities. Preliminary results from CFD modelling also show good agreement with experimental results.The research presented in this paper was supported by funding from the UK’s Engineering and Physical
Sciences Research Council (EPSRC) under grant EP/M017354/1
Quantum mechanical modeling of the multi-stage Stern\unicode{x2013}Gerlach experiment by Frisch and Segr\`e using the von Neumann equation
The multi-stage Stern\unicode{x2013}Gerlach experiment conducted by Frisch
and Segr\`e has been modeled analytically using quantum mechanics by Majorana
and revised by Rabi by including the hyperfine interaction. However, the
theoretical predictions do not match the experimental observation well. Here,
we numerically solve the standard quantum mechanical model, via the von Neumann
equation, that includes the hyperfine interaction for the time evolution of the
spin. The outcome is compared with the experimental observation and the
predictions by Majorana, Rabi, and an alternative model called co-quantum
dynamics. Thus far, the coefficients of determination from the standard quantum
mechanical model, which does not use free parameters, are still below zero.
Non-standard variants that improve the match are explored for discussion.Comment: 8 pages, 5 figure
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