625 research outputs found
Passive solar-energy air-heating wall panels
The development of products which enable passive solar-energy
air-heating to be integrated into the heating strategies of public,
commercial and industrial buildings is described. These buildings
are, in general, only occupied significantly during the day;
consequently the bulk of heating demand coincides with the period of
solar gain. In these circumstances collected solar heat should be
delivered with the minimum of delay.
The design and operation of units which are capable of supplying solar
heated air in this manner is outlined. These are passive, naturalcirculation
air-heating collectors, also known as natural-convection
air-heaters, or thermosyphoning air panels.
Four methods of retrofitting such solar collectors to non-domestic
buildings have been identified, one of which, the overcladding
collector, has not been proposed previously. Problems associated with
the successful installation and operation of these units have also
been considered.
The relative merits of a number of methods of testing passive solarenergy
air-heating collectors have been investigated. A method of
determining instantaneous collector efficiency based on the
measurement of glazing temperature, inlet and outlet air temperature,
ambient temperature and insolation has been developed.
Three novel design proposals have been presented: i) a collector
constructed with the insulation fitted outside, rather than inside, so
that the metal body of the collector may provide more symmetrical
heating of the air flow than the conventional arrangement, ii) an
absorber which consisted of parallel ducts to increase the rate of
heat transfer to the air, heating it symmetrically, (iii) a hinged
air-deflector for conversion from the heating to the ventilation mode
Hidden negative linear compressibility in lithium L-tartrateâ
Development of artificial muscles, next-generation pressure sensors and precision optics relies on advances in materials with anomalous mechanical properties. Negative linear compressibility, NLC, is one such rare, counterintuitive phenomenon, in which a material expands along one axis under hydrostatic pressure. Both classical and recent NLC materials face a pay-off between the active pressure range and magnitude of NLC, and in the vast majority of cases the NLC effect decreases with pressure. By decoupling the mechanical behaviour of building units for the first time in a winerack framework containing two different strut types, we show that lithium L-tartrate exhibits NLC with a maximum value, Kmax = -21 TPa^-1, and an overall NLC capacity, ÏNLC = 5.1 %, that are comparable to the most exceptional materials to date. Furthermore, the contributions from molecular strut compression and angle opening interplay to give rise to so-called âhiddenâ negative linear compressibility, in which NLC is absent at ambient pressure, switched on at 2 GPa and sustained up to the limit of our experiment, 5.5 GPa. Analysis of the changes in crystal structure using variable-pressure synchrotron X-ray diffraction reveals new chemical and geometrical design rules to assist the discovery of other materials with exciting hidden anomalous mechanical properties
Daylight: What Makes a Difference
Light is necessary for vision; it enables us to sense and perceive our surroundings and in many direct and indirect ways, via eye and skin, affects our physiological and psychological health. The use of light in built environments has comfort, behavioural, economic and environmental consequences. Daylight has many particular benefits including excellent visual performance, permitting good eyesight, effective entrainment of the circadian system as well as a number of acute non-image forming effects and the important role of vitamin D production. Some human responses to daylight seem to be well defined whilst others require more research to be adequately understood. This paper presents an overview of current knowledge on how the characteristics of daylight play a role in fulfilling these and other functions often better than electric lighting as conventionally delivered
Phase 3 Trial of 177Lu-Dotatate for Midgut Neuroendocrine Tumors
Background Patients with advanced midgut neuroendocrine tumors who have had disease progression during first-line somatostatin analogue therapy have limited therapeutic options. This randomized, controlled trial evaluated the efficacy and safety of lutetium-177 (177Lu)-Dotatate in patients with advanced, progressive, somatostatin-receptor-positive midgut neuroendocrine tumors. Methods We randomly assigned 229 patients who had well-differentiated, metastatic midgut neuroendocrine tumors to receive either 177Lu-Dotatate (116 patients) at a dose of 7.4 GBq every 8 weeks (four intravenous infusions, plus best supportive care including octreotide long-acting repeatable [LAR] administered intramuscularly at a dose of 30 mg) (177Lu-Dotatate group) or octreotide LAR alone (113 patients) administered intramuscularly at a dose of 60 mg every 4 weeks (control group). The primary end point was progression-free survival. Secondary end points included the objective response rate, overall survival, safety, and the side-effect profile. The final analysis of overall survival will be conducted in the future as specified in the protocol; a prespecified interim analysis of overall survival was conducted and is reported here. Results At the data-cutoff date for the primary analysis, the estimated rate of progression-free survival at month 20 was 65.2% (95% confidence interval [CI], 50.0 to 76.8) in the 177Lu-Dotatate group and 10.8% (95% CI, 3.5 to 23.0) in the control group. The response rate was 18% in the 177Lu-Dotatate group versus 3% in the control group (P<0.001). In the planned interim analysis of overall survival, 14 deaths occurred in the 177Lu-Dotatate group and 26 in the control group (P=0.004). Grade 3 or 4 neutropenia, thrombocytopenia, and lymphopenia occurred in 1%, 2%, and 9%, respectively, of patients in the 177Lu-Dotatate group as compared with no patients in the control group, with no evidence of renal toxic effects during the observed time frame. Conclusions Treatment with 177Lu-Dotatate resulted in markedly longer progression-free survival and a significantly higher response rate than high-dose octreotide LAR among patients with advanced midgut neuroendocrine tumors. Preliminary evidence of an overall survival benefit was seen in an interim analysis; confirmation will be required in the planned final analysis. Clinically significant myelosuppression occurred in less than 10% of patients in the 177Lu-Dotatate group. (Funded by Advanced Accelerator Applications; NETTER-1 ClinicalTrials.gov number, NCT01578239 ; EudraCT number 2011-005049-11
Optimising fisheries management in relation to tuna catches in the western central Pacific Ocean: A review of research priorities and opportunities
Some of the most important development goals for the countries and territories of the Western and Central Pacific Ocean (WCPO) involve the sustainable management of their fisheries in light of environmental, economic and social uncertainties. The responses of fish populations to variability in the marine environment have implications for decision making processes associated with resource management. There is still considerable uncertainty in estimating the responses of tuna populations to short-to-medium-term variability and longer-term change in the oceanic environment. A workshop was organised to examine how advances in oceanography, fisheries science and fisheries economics could be applied to the tuna fisheries of the WCPO and in doing so identify research priorities to improve understanding relevant to progressing management. Research priorities identified included: (i) improved parameterisation of end to end ecosystem model components, processes and feedbacks through expanded biological observations and incorporation of higher resolution climate models; (ii) development of seasonal and inter-annual forecasting tools enabling management responses to short-term variability in tuna distributions and abundances; (iii) improved understanding of the population dynamics of and the energy transfer efficiencies between food web components; (iv) assessment of the optimal value of access rights and overall fishery value under multiple scenarios of tuna distribution and abundance and influences on decision making by fisheries managers and fleets and (v) development of management strategy evaluation frameworks for utilisation in the implementing and testing of fishery management procedures and to help prioritise research directions and investment. Issues discussed and research priorities identified during the workshop have synergies with other internationally managed fisheries and therefore are applicable to many other fisheries
Ag(I) bipyridyl coordination polymers containing functional anions
The single crystal diffraction structures of seven coordination polymers formed by Ag(I) and bipyridyl azine ligands are described and compared. All contain organic anions derived from intrinsically functional molecules, either Active Pharmaceutical Ingredients (API = salicylate or diclofenac) or carboxylate or sulfonate monoazo dyes. Five of the seven coordination polymers, including all those that feature API species, are found to display variations on a common structural motif, with polymeric [Ag(azine)]n chains linked into pairs through argentophillic Ag-Ag contacts supported by a pair of AgOXOAg (X = C or S) bridges. Also reported are the crystal structures of two Ag(I) complexes of sulfonated monoazo dyes, including the first such structure to feature a Ag to azo dative bond
Sexual Size Dimorphism and Body Condition in the Australasian Gannet
Funding: The research was financially supported by the Holsworth Wildlife Research Endowment. Acknowledgments We thank the Victorian Marine Science Consortium, Sea All Dolphin Swim, Parks Victoria, and the Point Danger Management Committee for logistical support. We are grateful for the assistance of the many field volunteers involved in the study.Peer reviewedPublisher PD
Silicon potentials investigated using density functional theory fitted neural networks
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