746 research outputs found
Tacit knowledge, learning and expertise in dry stone walling
No full textThis is a detailed study of learning in the context of dry stone walling. It examines
what happens in the learning situation. The aim of this work was:
'To understand the nature of expertise in dry stone walling, how it is understood
by those practising the craft, and how it is transmitted to others'.
The main research questions were, therefore:
What happens when dry stone wallers are learning their craft?
How do they acquire expertise in dry stone walling?
How is this learning communicated?
This process necessitated developing a way of engaging with the practitioners,
eliciting descriptive data about what they were doing, and why they were doing it,
through interviews (or conversations) with both individuals and groups, whilst
they practiced their skill. Twenty three wailers were interviewed as they worked,
building walls.
The material obtained was analysed under seven different themes:
'Knowing how'
The use of tacit knowledge or intuition
'Flow'
Constant decision making, reflection and learning from mistakes
Individual and subjective variations and experiences
The relevance of emotion
The use of 'rules of thumb' or maxims.
Learning walling does not fit simply into any of the seven themes. It is
contextualised, complex and individual. It demonstrates tacit knowledge and
intuition. It involves emotion, sometimes consciously, sometimes not. It involves
memory, problem solving, and learning from mistakes, and reflection. Maxims or
'rules of thumb' were a key element in the learning process at all stages. Linear
stages of learning were not evidenced. Deep understanding of the practice is
evidenced, and the wider learning and teaching implications are explored
Effect of metabolic acidosis on intestinal absorption of calcium and phosphorus
No full text Page G480: U. Gafter, J. A. Kraut, D. B. N. Lee, V. Silis, M. W. Walling, K. Kurokawa, M. R. Haussler, and J. W. Coburn. “Effect of metabolic acidosis on intestinal absorption of calcium and phosphorus.” Page G480: M. W. Walling deceased 30 November 1979. </jats:p
Monitoring the fluvial palynomorph load in a lowland temperate catchment and its relationship to suspended sediment and discharge
No full textDespite it being a component of the seston we know very little about fluvial (waterborne) pollen and spore (palynomorph) transport. This paper presents the results of a monitoring programme conducted over two years and at a catchment scale in South West England. A hierarchical monitoring network was established with flood peak samples taken at 9 sub-catchments, intra-hydrograph samples taken in two sub-catchments and time-integrated sampling undertaken at one location. In addition sampling was undertaken of probable palynomorph sources such as channel bed and bank sediments, and the airborne pollen flux was monitored using modified Tauber traps. The results support previous research in illustrating how the vast majority of fluvial pollen and spores are transported during floods (91%) and that the main control on waterborne palynomorph assemblages is the catchment vegetation and its spatial distribution but with a long-distance (extra-catchment) component. However, strong seasonal effects are also shown, and the importance of distinctive sources such as the riparian input, bed re-suspension and overland flow into drains and tributaries is revealed. Fine sediment in river pools appears to act as a selective store of damaged cereal type pollen grains derived from arable fields. Although pollen does form part of composite particles the data presented here suggest that the majority of the pollen is transported as single grains. Fluvial palynomorph loading is strongly dependant upon discharge and so concentrations in laminated or varved sediments could be regarded as a proxy for flood magnitude
Aphids: Biology, Ecology, and Management
No full textPast studies have identified 18 species of aphids attacking tomato in open-field agriculture and greenhouses. However an in-depth review of the literature reveals only two species, Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer), as frequent and common aphid pests of tomato throughout the world. In this chapter, we review the identification, general biology, distribution, host range, and seasonal occurrence of these two aphids and discuss how they damage plants. We present research that has attempted to develop sampling strategies and devise economic thresholds. Furthermore, we review the history and current status of strategies used to manage M. euphorbiae and M. persicae. These strategies are presented under the broad headings of chemical control, biological control, host-plant resistance, cultural control, and others. With the wealth of information contained in this chapter, the reader will gain valuable insight into where we have been, and where we are likely to proceed in dealing with aphids on tomato
Modeling of SH- and P-SV-wave fields and seismic microzonation based on responsespectra for Talchir Basin, India
No full textThe P-SV- and SH-wave ␣eld in the Talchir Basin is simulated along eight pro␣les: four pro␣les strike across the basin and the other four along the basin. The hybrid method, which combines two computational techniques, modal summation and ␣nite differences, is used to produce multiphase synthetic seismograms. An M = 6 earthquake is considered, with hypocenter along the North Orissa Boundary Fault (NOBF) at a depth of 5 km and with the focal mechanism parameters: dip=90°, strike=160° and rake=180°. The peak acceleration (AMAX) along each pro␣le is determined considering the maximum acceleration obtained at the horizontal components. The response spectra ratio (RSR) as a function of frequency is computed for the eight pro␣les and the higher ampli␣cation is seen to increase in correspondence with the thicker sedimentary cover, especially for the radial component. Higher site ampli␣cation for all the pro␣les is observed in the frequency range from 0.5 to 1.4 Hz. To validate the obtained site-effects, the sources, for the pro␣les across the basin, are placed near to the southern end of the pro␣le and the site ampli␣cations are recomputed. Even if the spatial distribution of AMAX is mainly controlled by the epicentral distance, i.e. the geometrical spreading prevails on local soil effects, the RSR shows a pattern that can be easily correlated with the local site conditions. The RSR at the intersection of the pro␣les is dependent not only upon the local lithology and sediment thickness but also upon the epicentral distance. The Talchir Basin is classi␣ed into three zones based on the RSR values: low RSR zone (1.6–1.9), intermediate RSR zone (2.0–2.8) and high RSR zone (2.9– 5.2). The PGA estimated for the bedrock model by Bhatia et al. (1999) for the study region is around 0.05 to 0.10 g while the Indian seismic zonation map estimated it to be in the range from 0.1 to 0.2 g. In the present study, that considers the effects of lateral variations in the structure, the PGA is estimated to be as high as 0.55 g along the BA profile
Novel Dual Walling Cob Building: Dynamic Thermal Performance
No full textThis paper emphasizes the experimental and numerical study of new cob mixes used for insulation and load bearing wall elements. The experimental study provides complete datasets of thermal properties of the new walling materials, using cob with density ranging from 1107 kg/m3 to 1583 kg/m3 for structural walls and less than 700 kg m−3 for insulation walls. Various mixes of French soils and fibres (reed, wheat straw, hemp shiv, hemp straw, and flax straw) with different water contents are studied. The lowest average thermal conductivity is obtained for the structural cob mix prepared of 5% wheat straw and 31% of water content. The insulation mix, prepared with 25% reed and 31% water content, has the lowest thermal conductivity. Investigation of diffusivity, density, and heat capacity shows that, when thermal conductivity is lower than 0.4 W m−1 K−1, the decrease in cob density leads to better insulation values and higher heat capacity. Little variation is noticed regarding the density and heat capacity for cob mixes with thermal conductivity higher than 0.4 W m−1 K−1. Furthermore, the non-uniformity of local thermal conductivity and heat losses through the samples is due mainly to the non-uniform distribution of fibres inside the mixes inducing an increase in heat loss up to 50% for structural walls and 25% for insulation walls. Cob thermal properties are used in a comparative simulation case study of a typical house under French and UK climatic conditions. The energy performance of the conventional building is compared to a dual walled cob building, showing remarkable reduction in energy consumption as the cob walls, whilst maintaining comfortable indoor conditions without additional heating
Site-Specific Modeling of SH and P-SV Waves for Microzonation Study of Kolkata Metropolitan City, India
No full textWalling, Michael George (Birth, 1888-05-09)
No full textAddress: 95 Coleman2339/Pg 62/1888/M W/MW. Miss HardtOriginal record filed in drawer labeled 'WALKER-_WALTEN'
Recommended from our members
Hanford Works Report HW-60281 DEL
No full textA number of the questions which have been posed to us in the subject references are commented upon below. These have been reviewed by personanel of the Research and Engineering Operation and the Facilities Engineering Operation, Chemical Processing Department, and of the Chemical Research and Development Operation, Hanford Laboratories Operation. Particular acknowledment is given G. J Alkire, J. P. Duckworth, J. B. Fecht, R. G. Geier, E. R. Irish, H. M. Jones, G. C. Oberg, A. M. Platt, W. H. Reas, W. C. Schmidt, R. J. Sloat, W. H. Swift, M. T. Walling and L. L. Zahn of these organizations for assistance given assembling this information
Changes in Lateral Stress During Slurry Trench Wall Installation.
No full textPhDThe thesis is concerned with the effects of slurry trenching (diaphragm wall
installation) in an overconsolidated clay, with particular emphasis on the changes in
lateral stress which occur.
A review of the literature on diaphragm wall installation in stiff overconsolidated clay
was carried out, with particular reference to the measurement of changes in stress and
the application of finite element analyses. The problem was investigated by means of
centrifuge model tests and finite element analyses.
The main body of the thesis details the development and results of a series of
centrifuge tests. A model at 1 to 100 scale was tested at 100 gravities, enabling both
the long and short term effects of slurry trench walling to be investigated. The
technique adopted used a fluid-filled neoprene rubber bag in the place of the trench
that was drained to ground level to simulate excavation under bentonite slurry. A
mixture of plaster of Paris, iron-filings, fine sand and cement powder was then
deposited into the bag to simulate wall placement.
By using different fluid heights of different densities in the rubber bag, a series of
initial earth pressure coefficients were modelled. The effects of both a stress and
strain controlled boundary at the remote end of the model were also investigated.
Finally, simulated concretes of different densities were adopted to see what effect this
would have on placement stresses.
A technique was developed to enable the measurement of changes in total lateral
stress changes at up to 10 locations within the model. Pore water pressures were
measured at the same positions, and ground settlements were measured at the surface
of the model.
A series of finite element analyses was carried out to extend the scope of the
centrifuge model results by varying further the initial in situ conditions. The
conclusions and suggestions for further work are presented at the end of the thesis
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