1,175 research outputs found
Spatial repartition of local plastic processes in different creep regimes in a granular material
Granular packings under constant shear stress display below the Coulomb
limit, a logarithmic creep dynamics. However the addition of small stress
modulations induces a linear creep regime characterized by an effective viscous
response. Using Diffusing Wave Spectroscopy, we investigate the relation
between creep and local plastic events spatial distribution ("hot-spots")
contributing to the plastic yield. The study is done in the two regimes, i.e.
with and without mechanical activation. The hot-spot dynamics is related to the
material effective fluidity. We show that far from the threshold, a local
visco-elastic rheology coupled to an ageing of the fluidity parameter, is able
to render the essential spatio-temporal features of the observed creep
dynamics
Organometallic Ruthenium Complexes of Novel Thiosemicarbazones
We present the preliminary results of a study of two novel thiosemicarbazones (TSCs) and theirruthenium complexes. The TSCs were prepared by refluxing thiosemicarbazide with 9-anthraldehyde or benzanthrone in ethanol for 3 hours. The metal complex of each ligand (complex I =[(r|6 -C6H6 )Ru(9-ant-TSC )(C1)]C1 and complex II= [(r|6 -C6H6 )Ru(benz-TSC)(Cl)]Cl) was prepared by refluxing the appropriate TSC with [(r|6 -C6H6 )RuCl 2 ] r The compounds were characterized using infrared, ultraviolet-visible, and NMRspectroscopy. Two different methods, the disk diffusion test and luminometry, were used to test the compounds against a variety of different bacterial strains for antibacterial activity. The most optimistic results were obtained for the 9-ant-TSC ligand, especially in relation to activity against Gram (+) bacteria. The metal complexes showed no measurable activity and further biological testing of the metal complexes is currently being conducted
Uncertainty in the measurement of indoor temperature and humidity in naturally ventilated dairy buildings as influenced by measurement technique and data variability
[EN] The microclimatic conditions in dairy buildings affect animal welfare and gaseous emissions. Measurements are highly variable due to the inhomogeneous distribution of heat and humidity sources (related to farm management) and the turbulent inflow (associated with meteorologic boundary conditions). The selection of the measurement strategy (number and position of the sensors) and the analysis methodology adds to the uncertainty of the applied measurement technique.
To assess the suitability of different sensor positions, in situations where monitoring in the direct vicinity of the animals is not possible, we collected long-term data in two naturally ventilated dairy barns in Germany between March 2015 and April 2016 (horizontal and vertical profiles with 10 to 5 min temporal resolution). Uncertainties related to the measurement setup were assessed by comparing the device outputs under lab conditions after the on-farm experiments.
We found out that the uncertainty in measurements of relative humidity is of particular importance when assessing heat stress risk and resulting economic losses in terms of temperature-humidity index. Measurements at a height of approximately 3 m-3.5 m turned out to be a good approximation for the microclimatic conditions in the animal occupied zone (including the air volume close to the emission active zone). However, further investigation along this cross-section is required to reduce uncertainties related to the inhomogeneous distribution of humidity. In addition, a regular sound cleaning (and if possible recalibration after few months) of the measurement devices is crucial to reduce the instrumentation uncertainty in long-term monitoring of relative humidity in dairy barns (C) 2017 The Authors. Published by Elsevier Ltd on behalf of IAgrE.The work was financially supported by the German Federal Ministry of Food and Agriculture (BMEL) through the Federal Office for Agriculture and Food (BLE), grant number 2814ERA02C.Hempel, S.; König, M.; Menz, C.; Janke, D.; Amon, B.; Banhazi, T.; Estellés, F.... (2018). Uncertainty in the measurement of indoor temperature and humidity in naturally ventilated dairy buildings as influenced by measurement technique and data variability. Biosystems Engineering. 166:58-75. https://doi.org/10.1016/j.biosystemseng.2017.11.004S587516
Neutrino Oscillations in a Supersymmetric SO(10) Model with Type-III See-Saw Mechanism
The neutrino oscillations are studied in the framework of the minimal
supersymmetric SO(10) model with Type-III see-saw mechanism by additionally
introducing a number of SO(10) singlet neutrinos. The light Majorana neutrino
mass matrix is given by a combination of those of the singlet neutrinos and the
active neutrinos. The minimal SO(10) model gives an unambiguous Dirac
neutrino mass matrix, which enables us to predict the masses and the other
parameters for the singlet neutrinos. These predicted masses take the values
accessible and testable by near future collider experiments under the
reasonable assumptions. More comprehensive calculations on these parameters are
also given.Comment: 14 pages, 5 figures; the version to appear in JHE
The Caribbean needs big marine protected areas
The attached document is the author(’s’) final accepted/submitted version of the journal article. You are advised to consult the publisher’s version if you wish to cite from it
Ertragsbildung von unterschiedlichen Kulturarten für die Biogaserzeugung im ökologischen Landbau
Energy crops for biogas production need to be integrated into sustainable and site
adapted crop rotation systems, minimising the competition with food production.
Luzerne/clover (-grass), sun flower, maize, green-rye + maize and vetch-rye + maize
were compared at two sites in Austria with semi-arid (Raasdorf) and humid (Lambach)
conditions with and without biogas slurry application. The yield of legumes and
fertilised non-legumes at the humid site were 9 % to 56 % higher then at the semi-arid
site. The 2-crop system maize following vetch-rye achieved the highest yields at both
sites. Slurry from the biogas plant increased the yield only at the humid site
Determinants of Risk Behaviour in Livestock Development Programs: Evidence from South Africa's Kaonafatso Yadikgomo (Kyd) Scheme
Risk plays a significant role in input use decisions and production of output in agricultural production. Understanding farmer risk attitudes and their responses to risk is significant in designing effective intervention programmes. Few studies have tried to identify how the introduction of a livestock programme has tended to influence farmer risk profile. The objective of the study was to highlight the determinants of risk behaviour in participants of a livestock development programme. The study was carried out in KwaZulu-Natal (KZN) Province of South Africa, utilising a purposive sample of 164 respondents who are part of the Kaonafatso Yadikgomo (KYD) Scheme. The cross-sectional survey collected data pertaining to the risk attitudes of the livestock farmers from an attitudinal scale as well as socio-economic and farm biophysical characteristics. Descriptive statistics and multiple linear regression were used to analyse the data. The results show that the livestock farmers were risk loving, with the risk attitude being influenced by the age of household head, monthly household income and experience in rearing cattle at the ð‘ < 0.1 level. Furthermore, the source of income, herd size, reason for slaughtering cattle distance to the nearest water source and access to a dip tank had significant influence of attitude towards risk at the ð‘ < 0.05 level. The study concludes that being part of a livestock development programme tends inflto uence the risk attitudes of the participants as the determinants were against a priori expectations. 
Improving the Training of Frontline Extension Workers in Tanzania: A Pilot Curriculum Reform Initiative with the Ministry of Agriculture Training Institute at Ilonga
Promoting the transition of smallholder farmers from subsistence to more commercial and market-oriented production is an important goal of the Tanzanian extension system. The Ministry of Agriculture Training Institutes (MATIs) contribute to this goal by providing training to frontline extension workers (FEWs). However, the capacity of the MATI system to produce agricultural extension practitioners with job-ready competencies has declined, leading stakeholders and employers to raise concerns about the quality and training of FEWs. The main purpose of this study was to develop recommendations for curriculum revisions at MATI Ilonga to improve its program of study. This was done using a competency-based approach that incorporated inputs from stakeholders into the curriculum assessment and revision process. A panel of eight local and external experts derived 23 competencies from a review of the MATI curriculum and extension literature. A survey instrument to assess competencies based on perceptions of importance and graduates’ ability was designed and administered to 189 stakeholders from four stakeholder groups. Stakeholder-respondents considered all but two of the 23 competencies to be very high importance. Weighted discrepancy scores indicated that the highest rated areas for curriculum revision were Value Chains, Business skills, Climate Change, Fisheries, and Land Resource Management. All stakeholder groups except graduates, indicated Value Chains and Business Skills as high priorities requiring enhanced training to improve the ability of FEWs. Follow-up stakeholder consultations indicated support for using the competency-based approach, engaging stakeholders in the curriculum review process, and interest in applying the approach with other MATIs in Tanzania
Anaerobic digestion of whole-crop winter wheat silage for renewable energy production
With biogas production expanding across Europe in response to renewable energy incentives, a wider variety of crops need to be considered as feedstock. Maize, the most commonly used crop at present, is not ideal in cooler, wetter regions, where higher energy yields per hectare might be achieved with other cereals. Winter wheat is a possible candidate because, under these conditions, it has a good biomass yield, can be ensiled, and can be used as a whole crop material. The results showed that, when harvested at the medium milk stage, the specific methane yield was 0.32 m3 CH4 kg–1 volatile solids added, equal to 73% of the measured calorific value. Using crop yield values for the north of England, a net energy yield of 146–155 GJ ha–1 year–1 could be achieved after taking into account both direct and indirect energy consumption in cultivation, processing through anaerobic digestion, and spreading digestate back to the land. The process showed some limitations, however: the relatively low density of the substrate made it difficult to mix the digester, and there was a buildup of soluble chemical oxygen demand, which represented a loss in methane potential and may also have led to biofoaming. The high nitrogen content of the wheat initially caused problems, but these could be overcome by acclimatization. A combination of these factors is likely to limit the loading that can be applied to the digester when using winter wheat as a substrat
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