Studies in metal-ammonia reduction. Part 4. Reduction and reductive methylation of 7-methoxy-3,4-dihydrophenanthren-1(2H)-one and 7-methoxy-1,2-dihydrophenanthren-4(3H)-one

Birch reduction and reductive methylations of the title compounds have been investigated. 7-Methoxy-3,4-dihydrophenanthren-1(2H)-one (2) yields the cis-3,4,9,10,11,12-hexahydro-derivative (15) while the 7-methoxy-1,2-dihydrophenanthren-4(3H)-one (5) is reduced to the corresponding 1,2,9,10-tetrahydro-derivative (7). The factors influencing the mechanism of the reduction process have been discussed. The reductive methylation products of the ketone (2) are useful substrates in the synthesis of 9-methyl steroids.

Targeting resource investments to achieve sediment reduction and improved Great Barrier Reef health

Concerns about excessive sediment loads entering the Great Barrier Reef (GBR) lagoon in Australia have led to a focus on improving ground cover in grazing lands. Ground cover has been identified as an important factor in reducing sediment loads, but improving ground cover has been difficult for reef stakeholders in major catchments of the GBR. To provide better information an optimising linear programming model based on paddock scale information in conjunction with land type mapping was developed for the Fitzroy, the largest of the GBR catchments. This identifies at a catchment scale which land types allow the most sediment reduction to be achieved at least cost. The results suggest that from the five land types modelled, the lower productivity land types present the cheapest option for sediment reductions. The study allows more informed decision making for natural resource management organisations to target investments. The analysis highlights the importance of efficient allocation of natural resource management funds in achieving sediment reductions through targeted land type investments. © 2012.

AE energy release during the fracture of HSC beams

An attempt has been made experimentally to investigate the acoustic emission (AE) energy release in high-strength concrete (HSC) beams subjected to monotonically increasing load. Acoustic emission energy release during the fracture process of the HSC beams is measured. Stress waves released during the fracture process in materials cause acoustic emissions. AE energy released during the fracture of a notched three-point bend plain concrete beam specimens having 28-day compressive strengths of 50.0 MPa, 69.0 MPa and 78.0 MPa and mortar (cement: sand (1: 4) by weight) specimens are studied. Mortar consists of one part cement and four parts sand by weight. The specimens were tested by a material testing system of 1200 kN capacity employing crack mouth opening displacement control at the rate of 0.0004 mm/s. The fracture energy and the AE energy released during the fracture process of all the tested TPB and mortar specimens are compared and discussed. The observations made in the present experimental study have some applications for monitoring the integrity of structures.

Topographical, structural and geophysical characterization of fracture zones: implications for groundwater flow and vulnerability

The main objective of this study is to evaluate selected geophysical, structural and topographic methods on regional, local, and tunnel and borehole scales, as indicators of the properties of fracture zones or fractures relevant to groundwater flow. Such information serves, for example, groundwater exploration and prediction of the risk of groundwater inflow in underground construction. This study aims to address how the features detected by these methods link to groundwater flow in qualitative and semi-quantitative terms and how well the methods reveal properties of fracturing affecting groundwater flow in the studied sites. The investigated areas are: (1) the Päijänne Tunnel for water-conveyance whose study serves as a verification of structures identified on regional and local scales; (2) the Oitti fuel spill site, to telescope across scales and compare geometries of structural assessment; and (3) Leppävirta, where fracturing and hydrogeological environment have been studied on the scale of a drilled well. The methods applied in this study include: the interpretation of lineaments from topographic data and their comparison with aeromagnetic data; the analysis of geological structures mapped in the Päijänne Tunnel; borehole video surveying; groundwater inflow measurements; groundwater level observations; and information on the tunnel s deterioration as demonstrated by block falls. The study combined geological and geotechnical information on relevant factors governing groundwater inflow into a tunnel and indicators of fracturing, as well as environmental datasets as overlays for spatial analysis using GIS. Geophysical borehole logging and fluid logging were used in Leppävirta to compare the responses of different methods to fracturing and other geological features on the scale of a drilled well. Results from some of the geophysical measurements of boreholes were affected by the large diameter (gamma radiation) or uneven surface (caliper) of these structures. However, different anomalies indicating more fractured upper part of the bedrock traversed by well HN4 in Leppävirta suggest that several methods can be used for detecting fracturing. Fracture trends appear to align similarly on different scales in the zone of the Päijänne Tunnel. For example, similarities of patterns were found between the regional magnetic trends, correlating with orientations of topographic lineaments interpreted as expressions of fracture zones. The same structural orientations as those of the larger structures on local or regional scales were observed in the tunnel, even though a match could not be made in every case. The size and orientation of the observation space (patch of terrain at the surface, tunnel section, or borehole), the characterization method, with its typical sensitivity, and the characteristics of the location, influence the identification of the fracture pattern. Through due consideration of the influence of the sampling geometry and by utilizing complementary fracture characterization methods in tandem, some of the complexities of the relationship between fracturing and groundwater flow can be addressed. The flow connections demonstrated by the response of the groundwater level in monitoring wells to pressure decrease in the tunnel and the transport of MTBE through fractures in bedrock in Oitti, highlight the importance of protecting the tunnel water from a risk of contamination. In general, the largest values of drawdown occurred in monitoring wells closest to the tunnel and/or close to the topographically interpreted fracture zones. It seems that, to some degree, the rate of inflow shows a positive correlation with the level of reinforcement, as both are connected with the fracturing in the bedrock. The following geological features increased the vulnerability of tunnel sections to pollution, especially when several factors affected the same locations: (1) fractured bedrock, particularly with associated groundwater inflow; (2) thin or permeable overburden above fractured rock; (3) a hydraulically conductive layer underneath the surface soil; and (4) a relatively thin bedrock roof above the tunnel. The observed anisotropy of the geological media should ideally be taken into account in the assessment of vulnerability of tunnel sections and eventually for directing protective measures.

Drag reduction by a forward facing aerospike for a large angle blunt cone in high enthalpy flows

Drag reduction studies are conducted using a flat disc tipped aerospike for a 120-degree apex angle blunt cone model in high enthalpy flows. Accelerometer based force balance is used for the drag force measurement in the newly established free piston driven shock tunnel, HST3. Drag reduction upto about 58 percent has been achieved for Mach 8 flow of 5 MJ/kg specific enthalpy at zero degree angle of attack.

Drag reduction by counterflow supersonic jet for a blunt cone in high enthalpy flows

Counterflow supersonic jet is used as a drag reduction device during the experiments in free piston driven shock tunnel, HST3. Accelerometer based force balance is employed to measure the drag force experienced by the 60-degree apex angle blunt cone model without and with the supersonic jet opposing the hypersonic flow. It is observed that the drag force decreases with increase in injection pressure ratio until the critical injection pressure is reached. Maximum reduction in drag force of 44 percent is recorded at the critical injection pressure ratio 22.36. Further increase in injection pressure ratio has reduced the percentage drag reduction. Change in nature of the flowfield around the model has also been observed across the critical injection pressure ratio.

Experimental investigation of heat transfer reduction using forward facing cavity for missile shaped bodies flying at hypersonic speed

Forward facing circular nose cavity of 6 mm diameter in the nose portion of a generic missile shaped bodies is proposed to reduce the stagnation zone heat transfer. About 25% reduction in stagnation zone heat transfer is measured using platinum thin film sensors at Mach 8 in the IISc hypersonic shock tunnel. The presence of nose cavity does not alter the fundamental aerodynamic coefficients of the slender body. The experimental results along with the numerically predicted results is also discussed in this paper.

Impact of malnutrition on 12-month mortality following acute hip fracture

Background Studies investigating the relationship between malnutrition and post-discharge mortality following acute hip fracture yield conflicting results. This study aimed to determine whether malnutrition independently predicted 12-month post-fracture mortality after adjusting for clinically relevant covariates. Methods An ethics approved, prospective, consecutive audit was undertaken for all surgically treated hip fracture inpatients admitted to a dedicated orthogeriatric unit (November 2010–October 2011). The 12-month mortality data were obtained by a dual search of the mortality registry and Queensland Health database. Malnutrition was evaluated using the Subjective Global Assessment. Demographic (age, gender, admission residence) and clinical covariates included fracture type, time to surgery, anaesthesia type, type of surgery, post-surgery time to mobilize and post-operative complications (delirium, pulmonary and deep vein thrombosis, cardiac complications, infections). The Charlson Comorbidity Index was retrospectively applied. All diagnoses were confirmed by the treating orthogeriatrician. Results A total of 322 of 346 patients were available for audit. Increased age (P = 0.004), admission from residential care (P < 0.001), Charlson Comorbidity Index (P = 0.007), malnutrition (P < 0.001), time to mobilize >48 h (P < 0.001), delirium (P = 0.003), pulmonary embolism (P = 0.029) and cardiovascular complication (P = 0.04) were associated with 12-month mortality. Logistic regression analysis demonstrated that malnutrition (odds ratio (OR) 2.4 (95% confidence interval (CI) 1.3–4.7, P = 0.007)), in addition to admission from residential care (OR 2.6 (95% CI 1.3–5.3, P = 0.005)) and pulmonary embolism (OR 11.0 (95% CI 1.5–78.7, P = 0.017)), independently predicted 12-month mortality. Conclusions Findings substantiate malnutrition as an independent predictor of 12-month mortality in a representative sample of hip fracture inpatients. Effective strategies to identify and treat malnutrition in hip fracture should be prioritized.

Nitrogenase activity (acetylene reduction) associated with leaves of different cultivars of paddy

An investigation was conducted to study the levels of nitrogen fixation on the leaf or sheath surfaces of four cultivars of paddy plants by using acetylene reduction technique. Varying levels of positive nitrogenase activity were observed on all the leaf surfaces. Sheath of IET 1991 cultivar showed a higher rate of fixation than the leaf surface. All the nitrogen-fixing organisms on the leaf or sheath surfaces belonged to the genus Beijerinckia. There was no correlation between the bacterial density and the level of fixation. Scanning electron microscopic data revealed that the upper surface of IET 1991 leaf was highly silicified and the microflora was either scanty or nil while the lower surface appeared quite different and harboured more micro-organisms. Similarly, the inner surface of sheath was devoid of silicification and showed the presence of micro-organisms.

Nitrogenase activity (acetylene reduction) associated with leaves of different cultivars of paddy (Oryza sativa L.)

An investigation was conducted to study the levels of nitrogen fixation on the leaf or sheath surfaces of four cultivars of paddy plants by using acetylene reduction technique. Varying levels of positive nitrogenase activity were observed on all the leaf surfaces. Sheath of IET 1991 cultivar showed a higher rate of fixation than the leaf surface. All the nitrogen-fixing organisms on the leaf or sheath surfaces belonged to the genus Beijerinckia. There was no correlation between the bacterial density and the level of fixation. Scanning electron microscopic data revealed that the upper surface of IET 1991 leaf was highly silicified and the microflora was either scanty or nil while the lower surface appeared quite different and harboured more micro-organisms. Similarly, the inner surface of sheath was devoid of silicification and showed the presence of micro-organisms.

Topochemically controlled hydrogen reduction of scheelite-related rare-earth metal molybdates

Scheelite-related -Ln2Mo3O12(Ln = La, Pr, Nd, Sm, Gd, Tb, or Dy) oxides are reduced by hydrogen at 780–870 K yielding molybdenum (IV) oxides of formula Ln2Mo3O9. The latter crystallize in a tetragonal scheelite (ABO4) type structure where one third of the A sites and a quarter of the anion sites are vacant: Ln2/3(cat)1/3MoO3(an). The reaction Ln2Mo3O12+ 3H2 Ln2Mo3O9(an)3+ 3H2O may be regarded as topochemically controlled, since both the parent and the product phases have scheelite-related structures. Infrared spectra and electrical and magnetic properties of these metastable defect scheelite phases are reported.