1,204 research outputs found
The state and community media
The recent floods in Chennai and Tamilnadu highlighted the consequences of unregulated construction of IT corridors, gated communities, informal habitations on land adjacent to water ways and reclaimed marsh land. In the absence of any explicit help from the state, the Indian Army and ordinary citizens pitched in to help neighbours and strangers in the immediate aftermath of the destruction. Arguably, people acted as the Fourth Estate, and the widespread use of social media helped mobilise relief and self-help groups to identify areas and communities isolated by the floods, strengthen the networking of NGOs involved in relief work and augment the work of the army and the state
The ambivalent state and the media in India: between elite domination and the public interest
The inability of the state in India to either translate existing media policies into practice, or create media policies and regulatory processes that correspond with the emergent reality of convergent media, is a reflection of its ambivalence-caught as if were between the demands from its interests groups and the compulsions stemming from the need to engage with a populist politics. This article explores issues related to the emerging political economy of communications in India with a specific emphasis on the nature of media ownership and control within a media market that is increasingly controlled by business interests and political parties. It also tries to make sense of the efficacy of counter-movements including community radio, free and open source software
The empowerment potential of public sector software (PSS)
Investigations into the potential for public sector software (PSS) to empower citizens are at a very nascent stage. This article explores the theoretical basis for, and practical advantages of, PSS, in the making of an informed and pro-active citizenry. Using the example of the emerging PSS movement in India and in particular the ICT literacy movement in Kerala, South India, it argues, that access to and use of software based on the principles of free and open source has the potential to contribute to an empowered citizenry. However the very concept of PSS is contested by major private software companies given that they stand to lose from public investments that are based on open standards. The article argues that PSS can contribute to the making of an âinformation commonsâ and that the need of the hour is for innovative and creative solutions to the information deficits faced by communities in India and elsewhere
Insurance loss coverage and social welfare
Restrictions on insurance risk classification may induce adverse selection, which is usually perceived as a bad outcome, both for insurers and for society. However, a social benefit of modest adverse selection is that it can lead to an increase in `loss coverage', defined as expected losses compensated by insurance for the whole population. We reconcile the concept of loss coverage to a utilitarian concept of social welfare commonly found in economic literature on risk classification. For iso-elastic insurance demand, ranking risk classification schemes by (observable) loss coverage always gives the same ordering as ranking by (unobservable) social welfare
Vinylene-Linked Covalent Organic Frameworks by Base-Catalyzed Aldol Condensation
Two 2D covalent organic frameworks (COFs) linked by vinylene (âCH=CHâ) groups (VâCOFâ1 and VâCOFâ2) are synthesized by exploiting the electron deficient nature of the aromatic sâtriazine unit of C3âsymmetric 2,4,6âtrimethylâsâtriazine (TMT). The acidic terminal methyl hydrogens of TMT can easily be abstracted by a base, resulting in a stabilized carbanion, which further undergoes aldol condensation with multitopic aryl aldehydes to be reticulated into extended crystalline frameworks (VâCOFs). Both VâCOFâ1 (with terepthalaldehyde (TA)) and VâCOFâ2 (with 1,3,5âtris(pâformylphenyl)benzene (TFPB)) are polycrystalline and exhibit permanent porosity and BET surface areas of 1341â
m2âgâ1 and 627â
m2âgâ1, respectively. Owing to the close proximity (3.52â
Ă
) of the preâorganized vinylene linkages within adjacent 2D layers stacked in eclipsed fashion, [2+2] photoâcycloadditon in VâCOFâ1 formed covalent crosslinks between the COF layers.TU Berlin, Open-Access-Mittel - 2019DFG, 390540038, EXC 2008: UniSysCa
Insurance loss coverage under restricted risk classification: The case of iso-elastic demand
This paper investigates equilibrium in an insurance market where risk classification is restricted. Insurance demand is characterised by an iso-elastic function with a single elasticity parameter. We characterise the equilibrium by three quantities: equilibrium premium; level of adverse selection (in the economistâs sense); and âloss coverageâ, defined as the expected population losses compensated by insurance. We consider both equal elasticities for high and low risk-groups, and then different elasticities. In the equal elasticities case, adverse selection is always higher under pooling than under risk-differentiated premiums, while loss coverage first increases and then decreases with demand elasticity. We argue that loss coverage represents the efficacy of insurance for the whole population; and therefore that if demand elasticity is sufficiently low, adverse selection is not always a bad thing
REMAINING LIFE ASSESSMENT AND PERFORMANCE CHARACTERIZATION OF CENTRIFUGAL COMPRESSORS IN LNG TRAINS
LectureRasGas LNG Trains-1 and 2, comprising of three
refrigeration centrifugal compressors each, were commissioned
in 1999 and 2000, respectively. Three compressors have
achieved 15 years of trouble free operation through risk based
Predictive and Preventive Maintenance Strategies and
surveillance program. None of these compressorsâ major
components such as the rotor, dry gas seals or bearings have
been replaced so far except three cases due to design upgrades
(Rotor Re-rate, Thrust Disk fretting issue). Industry and
technical literature survey indicates that several hundred
compressors have achieved service life of over 20 years.
However, the frequencies of maintenance interventions are not
common/standardized due to site specific variations, shutdown
3rd Middle East Turbomachinery Symposium (METS III)
15-18 February 2015 | Doha, Qatar | mets.tamu.edu
Copyright© 2015 by RasGas Co. Ltd, Qatar, and Turbomachinery Laboratory, Texas A and M Engineering Experiment Station
2
windows and differences in applications. In the LNG business, major maintenance activities of these compressors are required to be aligned with Gas Turbine Driverâs 8 yearly Major-Inspection Cycles to avoid extended outages and very high adverse economic consequences. Train-1/2 compressorsâ running life would exceed 23 years, well beyond API recommended service life of 20 years, when the next Gas Turbine Major-Inspection (MI) is scheduled.
This Paper presents Engineering Studies on these six Compressors for the assessment of all potential failure modes, estimating remaining operational life and identifying requisite life-extension recommendations for meeting the challenge of achieving failure free operation for the extended period of 8 years. The compressor components are susceptible to low and high cycle fatigue, erosion, corrosion, creep, wear, and accumulated damages resulting in performance degradation and may eventually lead to failures. Review of rotor-dynamic design and performance, head/end wall O-ring life estimation, balancing drum condition review, and acoustic mapping were performed to evaluate the compressor train reliability and to benchmark the current system performance. To predict the static and dynamic stress distribution on compressor impellers (14 in total), detailed finite element (FE) models of the impellers are developed and validated using results from modal testing of spare impellers. The stress predictions using conservative estimates of alternating fluid pressure loads and rotor spin motion as forcing functions allow computing the impeller endurance limit, i.e., the stress limit corresponding to its infinite life. A stress based life prediction method, using Goodman diagram, was used to determine the impeller margin of safety.
Aerodynamic excitations and structural resonant vibrations mostly contribute to the acoustic emissions. Non-intrusive acoustic and vibration measurements were performed near the compressors and piping to benchmark the current operating condition of the system, which will serve for future Condition monitoring and periodic system evaluation. Rotordynamic response measurements from bode plot, waterfall plots, and orbit plots was reviewed to identify the rotor critical speeds, sub-synchronous whirl, rotor misalignment, and rubbing. The compressor efficiency and pressure ratios are characterized and trends developed to evaluate historic performance. This study for the assessment of the remaining life of centrifugal compressors provides a reference for development of long term maintenance philosophy for all RasGas LNG trains and gas processing plants
Instantaneous Capture and Mineralization of Flue Gas Carbon Dioxide: Pilot Scale Study
Multiple CO2 capture and storage (CCS) processes are required to address anthropogenic CO2 problems. However, a method which can directly capture and mineralize CO2 at a point source, under actual field conditions, has advantages and could help offset the cost associated with the conventional CCS technologies. The mineral carbonation (MC), a process of converting CO2 into stable minerals (mineralization), has been studied extensively to store CO2. However, most of the MC studies have been largely investigated at laboratory scale. Objectives of this research were to develop a pilot scale AMC (accelerated mineral carbonation) process and test the effects of flue gas moisture content on carbonation of fly ash particles. A pilot scale AMC process consisting of a moisture reducing drum (MRD), a heater/humidifier, and a fluidized-bed reactor (FBR) was developed and tested by reacting flue gas with fly ash particles at one of the largest coal-fired power plants (2120 MW) in the USA. The experiments were conducted over a period of 2 hr at ~ 300 SCFM flow-rates, at a controlled pressure (115.1 kPa), and under different flue gas moisture contents (2-16%). The flue gas CO2 and SO2 concentrations were monitored before and during the experiments by an industrial grade gas analyzer. Fly ash samples were collected from the reactor sample port from 0-120 minutes and analyzed for total inorganic carbon (C), sulfur (S), and mercury (Hg). From C, S, and Hg concentrations, %calcium carbonate (CaCO3), %sulfate (SO42-), and %mercury carbonate (HgCO3) were calculated, respectively. Results suggested significant mineralization of flue gas CO2, SO2, and Hg within 10-15 minutes of reaction. Among different moisture conditions, ~16% showed highest conversion of flue gas CO2 and SO2 to %CaCO3 and %SO42- in fly ash samples. For example, an increase of almost 4% in CaCO3 content of fly ash was observed. Overall, the AMC process is cost-effective with minimum carbon footprint and can be retrofitted to coal fired power plants (existing and/or new) as a post-combustion unit to minimize flue gas CO2, SO2, and Hg emissions into the atmosphere. Used in conjunction with capture and geologic sequestration, the AMC process has the potential to reduce overall cost associated with CO2 separation/compression/transportation/pore space/brine water treatment. It could also help protect sensitive amines and carbon filters used in flue gas CO2 capture and separation process and extend their life
Improving insurance with some adverse selection
Public policy on insurance risk classification is typically perceived as a trade-off between two types of argument. On the one hand, social arguments against discrimination suggest a need for limits on insurersâ ability to use individual data in setting premiums. On the other hand, economic arguments under the rubric of âadverse selectionâ or âanti-selectionâ suggest that such limits make insurance markets work less well
Loss coverage in insurance markets: why adverse selection is not always a bad thing
This paper investigates equilibrium in an insurance market where risk classification is restricted. Insurance demand is characterised by an iso-elastic function with a single elasticity
parameter. We characterise the equilibrium by three quantities: equilibrium premium; level of adverse selection; and âloss coverageâ, defined as the expected population losses compensated
by insurance. We find that equilibrium premium and adverse selection increase monotonically with demand elasticity, but loss coverage first increases and then decreases. We argue that
loss coverage represents the efficacy of insurance for the whole population; and therefore, if demand elasticity is sufficiently low, adverse selection is not always a bad thing
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