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Thermal performance of radiant floor heating systems concrete slabs
Get PDFThis paper investigates the application of recycled steel powder as an additive in concrete to increase the thermal properties of radiant floor heating systems. The project aimed to increase the efficiencies of thermal conductivities, allowing radiant heat to produce higher energy-efficient outputs for heating. Thermocouple readings measured lower temperatures with similar heating conditions as a standard mix slab due to heat transfer occurring evenly through a large surface area, thus transferring heat to the air at faster rates. The tests were completed by casting two 400 × 400 × 200 mm (width × length × depth) slabs enclosing radiant heating pipes. Water was pumped at 40 and 60°C through the pipes. The temperature was recorded at various positions throughout the slab that would allow the multi-layered cylinder approach to analyse the rate of heat transfer, and calculate the efficiency of the heat transfer. The crushing strength of the proposed mix using steel powder replacement is shown to be reduced by 26% when a mix with 12.4% of steel powder is used. Contrary to the original hypothesis of this research, the investigation found rates of heat transfer during the heating stage were 3% lower for the mix containing steel powder compared to the standard mix
Biologically active Amaryllidaceae alkaloids in Narcissus pseudonarcissus cv. Carlton and Andrew’s Choice dormant bulbs
Get PDFSince the ancient times, Amaryllidaceae genus Narcissus has been reported for the production of biologically important alkaloids, many of which are used as therapeutic tools for human diseases. Among them, galanthamine (Gal) has received a considerable attention for its acetylcholinesterase inhibitory activity for the treatment of early to mid-stage Alzheimer’s diseases. In this study, gas chromatography-mass spectrophotometry was used to determine the galanthamine content along with the detection of other biologically important alkaloids in dormant bulb and basal plate of two cultivated varieties of Narcissus pseudonarcissus, Carlton and Andrew’s Choice. The amount of galanthamine was higher in Carlton bulb (860 µg Gal/g) and basal plate (1254 µg Gal/g) than Andrew’s Choice bulb (674 µg Gal/g) and basal plate (1051 µg Gal/g). Non-dormant Carlton bulb was used as control, which represented the galanthamine content of 1117 µg Gal/g. Besides galanthamine, other biologically important alkaloids were detected in Carlton such as lycoramine, lycorine, lycorenine, crinamine, and pancracine; while tazettine, oxoassoanine, lycorine, and o-methyl-macronine were detected in Andrew’s Choice. Findings of this study suggest that both Narcissus cultivars could be the important sources for the isolation of naturally occurring bioactive alkaloids for their commercial availability and could be potentially used in pharmaceuticals
Human-ecodynamics and the intertidal zones of the Zanzibar Archipelago
Get PDFThe intertidal zone, covering the nearshore fringe of coasts and islands and extending from the high-water mark to areas that remain fully submerged, encompasses a range of habitats containing resources that are as important to modern populations as they were to humans in prehistory. Effectively bridging land and sea, intertidal environments are extremely dynamic, requiring complexity and variability in how people engaged with them in the past, much as they do in the present. Here we review and reconsider environmental, archaeological, and modern socio-ecological evidence from the Zanzibar Archipelago on eastern Africa's Swahili coast, focusing on marine molluscs to gain insight into the trajectories of human engagement with nearshore habitats and resources. We highlight the potential drivers of change and/or stability in human-intertidal interactions through time and space, set against a backdrop of the significant socio-economic and socio-ecological changes apparent in the archipelago, and along the Swahili coast, during the late Holocene.</p
Reliability of environmental DNA surveys to detect pond occupancy by newts at a national scale
Get PDFThe distribution assessment and monitoring of species is key to reliable environmental impact
assessments and conservation interventions. Considerable efort is directed towards survey and
monitoring of great crested newts (Triturus cristatus) in England. Surveys are increasingly undertaken
using indirect methodologies, such as environmental DNA (eDNA). We used a large data set to
estimate national pond occupancy rate, as well as false negative and false positive error rates, for
commercial eDNA protocols. Additionally, we explored a range of habitat, landscape and climatic
variables as predictors of pond occupancy. In England, 20% of ponds were estimated to be occupied
by great crested newts. Pond sample collection error rates were estimated as 5.2% false negative
and 1.5% false positive. Laboratory error indicated a negligible false negative rate when 12 qPCR
replicates were used. Laboratory false positive error was estimated at 2% per qPCR replicate and is
therefore exaggerated by high levels of laboratory replication. Including simple habitat suitability
variables into the model revealed the importance of fish, plants and shading as predictors of newt
presence. However, variables traditionally considered as important for newt presence may need more
precise and consistent measurement if they are to be employed as reliable predictors in modelling
exercises
Fishmonger’s Swallet, Alveston, Gloucestershire, radiocarbon dating
Get PDFDetails are given of the eleven radiocarbon dates which have been obtained on specimens from Fishmonger’s Swallet, Alveston. Although the first dates to be obtained are generally rather younger than the latest ones, all appear to come from material deposited in the late pre-Roman Iron Age
Manganese stabilization in mine tailings by MgO-loaded rice husk biochar: Performance and mechanisms
Get PDFLeachable metal in abandoned mine tailings may be toxic to vegetation, affecting effective ecological restoration. In this study, MRB was synthesized through MgCl2·6H2O wet impregnation followed by duplicate slow pyrolysis. Manganese tailings were mixed with MRB, rice husk biochar (RB), and MgO at a dosage of 0-5%, followed by 90-day incubation. Toxicity characteristic leaching procedure and sequential leaching were used to analyze the leachability and species of Mn in tailings, while a stabilization mechanism was proposed with the support of the characterization of the tailings before and after amendment. Results suggested MRB addition significantly decreased leachable Mn by 63.8%, reducing from 59.88 mg/L to 21.68 mg/L, while only a 14.39% reduction was achieved by rice husk biochar (RB). The sharp decline of leachable Mn after 90-day mixing was contributed by the transformation from labile to stable fractions. A microporous biochar matrix along with the uniform dispersion of MgO active component were both responsible for the better Mn stabilization. Only less than 10% of the variation in substrate pH was observed with the increase of MgO loading or incubation time. Linear correlation analyses indicated substrate pH’s strong negative relationship with leachable Mn and moderate positive relationship with residual fraction. Characterization results revealed that MRB exhibited different stabilization mechanisms in mine tailings, where Mn was likely to be stabilized by direct interaction with active MgO or indirect alkaline precipitation to form stable MgMn2O4, Mn(CH3COO)2, and MnO(OH)2. This work validated the promoting potential of recycling agricultural biomass waste for the amendment of manganese mine tailings
No-mow amenity grassland case study: Phenology of floral abundance and nectar resource
Get PDF1. Popular campaigns such as No Mow May seek to encourage early-season forage
resource for pollinators in urban green spaces. Land managers need to balance
ecological benefits with extent of accessible amenity grassland.
2. To pilot the identification of a ‘tipping point’ when the nectar resource of unmown
grassland exceeds that mown, we surveyed floral abundance in 30 plots on an
amenity grassland site at 11 time points between late April and July. Each species’
floral abundance per 1 m2 was multiplied by published nectar sugar values to obtain
an overall nectar sugar value per plot.
3. The nectar sugar value of no-mow plots was overall significantly higher than for
mown plots. However, week-by-week analysis revealed that the first significant difference did not occur until mid-late May when no-mow plots yielded three times
the nectar sugar value of the mown plots. In early-mid June, there was a significant
eightfold divergence followed by a late June to early July decline. Common Ragwort
(Senecio jacobaea) provided the greatest nectar sugar value, driving significant differences again in mid-July. No-mow plots contained twice as many (22 vs. 11) open
flower broadleaf species compared to the mown plots.
4. Land managers could consider extending No Mow May management into June
and beyond to maximize nectar sugar resource for pollinators. To comply with
S. jacobaea legislation, a management plan and financial resource should be
allocated to no-mow projects