59 research outputs found
On a new (21_4) polycyclic configuration
When searching for small 4-configurations of points and lines, polycyclic
configurations, in which every symmetry class of points and lines contains the
same number of elements, have proved to be quite useful. In this paper we
construct and prove the existence of a previously unknown (21_4) conguration,
which provides a counterexample to a conjecture of Branko Gr\"unbaum. In
addition, we study some of its most important properties; in particular, we
make a comparison with the well-known Gr\"unbaum-Rigby configuration. We show
that there are exactly two (21_4) geometric polycyclic configurations and
seventeen (21_4) combinatorial polycyclic configurations. We also discuss some
possible generalizations.Comment: 22 pages, 12 figure
Combustion generated fine carbonaceous particles
Soot is of importance for its contribution to atmospheric particles with their adverse health impacts and for its contributions to heat transfer in furnaces and combustors, to luminosity from candles, and to smoke that hinders escape from buildings during fires and that impacts global warming or cooling. The different chapters of the book adress comprehensively the different aspects from fundamental approaches to applications in technical combustion devices
Coconut oil and its derivatives as a renewable alternative diesel fuel for use in the Maldives
Maldives is a small country without any conventional energy resources and
desperately needs alternative means to power their industry.
The work assesses the suitability of coconut oil as an alternative diesel fuel for the
use on the individual islands of the Maldives.
A study was carried out to identify the availability of resources relative to the energy
requirements of the country and coconuts became the most suitable candidate to
produce an alternative fuel for the existing diesel engines.
For the study on the long term effects of coconut oil and its derivatives (Methyl and
Ethyl Esters) a single cylinder direct injection Lister-Petter engine model AD I was
used. The engine was equipped for continous condition monitoring using a data
acquisition system. The system measures the in-cylinder and fuel injection pressures
relative to the crank angle. Also the cylinder and exhaust temperatures were measured
for all the fuels. Since the viscosity of the crude coconut oil is relatively high
compared to diesel a transesterification process was developed to reduce the viscosity
and this gave very good results. The physical and chemical properties of the fuels
were measured.
The engine was initially tested using a 20h test cycle with each fuel and this was
followed by a 200h test cycle on COIL. The engine performance was mapped in
terms of speed, load, volumetric fuel and air flow. In addition, exhaust gas analysis
was carried out to measure the regulated emissions. Tenax glass fibre, coconut
charcoal filters and dinitropheny1hydrazone tubes were used to sample the
unregulated emissions. The pressures and temperatures were continuously observed
and recorded at intervals. The ignition delay measurements showed that COIL and
COME had shorter ignition delay periods compared to diesel fuel.
During the tests engine lubricating oil was checked for possible fuel dilution. After
every 100 engine running hours, the engine was opened and physically inspected for
wear and damage, as well as for carbon and lacquer deposits. Pictures were taken of
the cylinder liner, piston top and cylinder head. The fuel injector was removed and
tested on the fuel injector test rig. The results were favourable and also the scanning
electron microscope measurements of the injector nozzle show that the deposits were
low when compared to diesel. A novel non-intrusive combustion chamber deposit
thickness measuring system was developed to measure the deposit thickness.
A separate rig was built using a similar type of fuel injection system as that on the
engine for fuel spray studies. Initially fuel spray photography was done using a high
speed camera to determine the pattern of the spray, spray penetration rate and the
cone angle for the three fuels. Once this was established a Malvern particle sizing
system was used to measure the droplet sizes for all fuels.
The results of the spray experiments helped to explain differences observed in the
engine performance for the different fuels. All the work carried out to date supports
the use of coconut oil as an alternative fuel for diesel engines in the Maldives
Gas Capture Processes
This book introduces the recent technologies introduced for gases capture including CO2, CO, SO2, H2S, NOx, and H2. Various processes and theories for gas capture and removal are presented. The book provides a useful source of information for engineers and specialists, as well as for undergraduate and postgraduate students in the fields of environmental and chemical science and engineering
Recommended from our members
The extraction of bitumen from western oil sands: Volume 2. Final report
The program is composed of 20 projects, of which 17 are laboratory bench or laboratory pilot scale processes or computer process simulations that are performed in existing facilities on the University of Utah campus in north-east Salt Lake City. These tasks are: (1) coupled fluidized-bed bitumen recovery and coked sand combustion; (2) water-based recovery of bitumen; (3) oil sand pyrolysis in a continuous rotary kiln reactor; (4) oil sand pyrolysis in a large diameter fluidized bed reactor; (5) oil sand pyrolysis in a small diameter fluidized bed reactor; (6) combustion of spent sand in a transport reactor; (7) recovery and upgrading of oil sand bitumen using solvent extraction methods; (8) fixed-bed hydrotreating of Uinta Basin bitumens and bitumen-derived hydrocarbon liquids; (9) ebullieted bed hydrotreating of bitumen and bitumen derived liquids; (10) bitumen upgrading by hydropyrolysis; (11) evaluation of Utah`s major oil sand deposits for the production of asphalt, high-energy jet fuels and other specialty products; (12) characterization of the bitumens and reservoir rocks from the Uinta Basin oil sand deposits; (13) bitumen upgrading pilot plant recommendations; (14) liquid-solid separation and fine tailings thickening; (15) in-situ production of heavy oil from Uinta Basin oil sand deposits; (16) oil sand research and development group analytical facility; and (17) process economics. This volume contains reports on nine of these projects, references, and a bibliography. 351 refs., 192 figs., 65 tabs
Research and Technology, 1994
This report selectively summarizes the NASA Lewis Research Center's research and technology accomplishments for the fiscal year 1994. It comprises approximately 200 short articles submitted by the staff members of the technical directorates. The report is organized into six major sections: Aeronautics, Aerospace Technology, Space Flight Systems, Engineering and Computational Support, Lewis Research Academy, and Technology Transfer. A table of contents and author index have been developed to assist the reader in finding articles of special interest. This report is not intended to be a comprehensive summary of all research and technology work done over the past fiscal year. Most of the work is reported in Lewis-published technical reports, journal articles, and presentations prepared by Lewis staff members and contractors. In addition, university grants have enabled faculty members and graduate students to engage in sponsored research that is reported at technical meetings or in journal articles. For each article in this report a Lewis contact person has been identified, and where possible, reference documents are listed so that additional information can be easily obtained. The diversity of topics attests to the breadth of research and technology being pursued and to the skill mix of the staff that makes it possible
Constant-Volume Carbonization of Biomass.
Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018
Evaluating ecosystem interventions for improved health outcomes - The case of the Volta Estuary mangroves and malaria
Degradative alteration of ecological systems worldwide is progressing at a time when their influence on human wellbeing is becoming more evident. For some ecosystems and aspects of wellbeing, more concrete knowledge exists. Insights into the science of mangrove-health relationships are however limited and fragmented, with no assessments of human perspectives around these phenomena. This study investigated the nature of the mangrove-human health nexus by assessing the impacts of mangrove ecosystem interventions on health-related ecosystem goods and services and self-reported malaria experiences. Using a mix of methods comprising a systematic literature review, key informant interviews, health questionnaires and Qualitative Comparative Analysis (QCA), this study merges three bodies of work. Research participant viewpoints were synthesised regarding the evolution of mangrove characteristics and use patterns over time, and how these are affected by ecosystem restoration. Survey respondents were also engaged in a recall exercise of malaria experiences over the same period, to provide a basis for causal inference analysis using QCA methodology. Results show that mangrove dependence is declining with ecosystem degradation in Ghana, but ecosystem restoration can modulate some negative health impacts of mangrove degradation, such as infectious disease risk and threats to protein nutrition. Further, specific ecological conditions elicited by ecosystem interventions work together diversely to decrease malaria incidence, but mainly to amplify benefits of current malaria vector control interventions. The causal relationships reveal that certain aspects of wetland restoration can be strengthened to deliver conditions that improve consequences of current malaria management strategies. Environment and health managers must collaborate in policy reorientation, monitoring, evaluation, and capacity building to realise more tangible scientific evidence and sustainable cross-sector outcomes. Ecosystem interventions could plug the shortfalls arising from resource constraints in health policy implementation, towards more uniform outcomes especially in marginal communities
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