Ammonia Production from a Non-Grid Connected Floating Offshore Wind-Farm: A System-Level Techno-Economic Review

According to U.S. Department of Energy, offshore wind energy has the potential to generate 7,200 TWh of energy annually, which is nearly twice the current annual energy consumption in the United States. With technical advances in the offshore wind industry, particularly in the floating platforms, windfarms are pushing further into the ocean. This creates new engineering challenges for transmission of energy from offshore site to onshore. One possible solution is to convert the energy produced into chemical energy of ammonia, which was investigated by Dr. Eric Morgan. In his doctoral dissertation, he assessed the technical requirements and economics of a 300 tons/day capacity ammonia plant powered by offshore wind. However, in his dissertation, one of the assumptions was connection to the grid which provided auxiliary power to keep the ammonia plant operational and produce at rated capacity. It also allowed selling of excess power to the grid in the scenario of excess power production by wind farm during high winds. This thesis explores the technical and economical feasibility of a similar system, except that the ammonia plant will be on a plantship and there is no connection to the grid. This creates a challenge as the ammonia synthesis plant must operate between 65-100% loads. Thus, the concept of multiple mini-ammonia plants is used to address the scenario of wind energy production at less than rated power. This will allow operation of one or more mini-ammonia plant (corresponding to the available energy from offshore wind). In the event of wind speed lower than the cutoff wind speed for the turbine, the ammonia plant will use the produced ammonia as fuel, with the help of a gas turbine running on either Brayton cycle or combined cycle, to keep the plant idling. It will maintain the reaction conditions of the synthesis chamber and will not produce any ammonia. This is an important step as it takes days to reach the reaction conditions to start ammonia production again after shutting down due to unavailability of energy at low winds. Thus, at any windspeed, a mini-ammonia plant would either idle or operate between 65-100% load. This model will be used to simulate the total energy consumption, total energy captured by the wind farm, and the total ammonia produced. This will further help in assessing the final cost of producing, transporting, and consuming ammonia as fuel and thereby provide a better understanding of the feasibility of implementing this technology. According to U.S. Department of Energy, offshore wind energy has the potential to generate 7,200 TWh of energy annually, which is nearly twice the current annual energy consumption in the United States. With technical advances in the offshore wind industry, particularly in the floating platforms, windfarms are pushing further into the ocean. This creates new engineering challenges for transmission of energy from offshore site to onshore. One possible solution is to convert the energy produced into chemical energy of ammonia, which was investigated by Dr. Eric Morgan. In his doctoral dissertation, he assessed the technical requirements and economics of a 300 tons/day capacity ammonia plant powered by offshore wind. However, in his dissertation, one of the assumptions was connection to the grid which provided auxiliary power to keep the ammonia plant operational and produce at rated capacity. It also allowed selling of excess power to the grid in the scenario of excess power production by wind farm during high winds.\\ \par This thesis explores the technical and economical feasibility of a similar system, except that the ammonia plant will be on a plantship and there is no connection to the grid. This creates a challenge as the ammonia synthesis plant must operate between 65-100\% loads. Thus, the concept of multiple mini-ammonia plants is used to address the scenario of wind energy production at less than rated power. This will allow operation of one or more mini-ammonia plant (corresponding to the available energy from offshore wind). In the event of wind speed lower than the cutoff wind speed for the turbine, the ammonia plant will use the produced ammonia as fuel, with the help of a gas turbine running on either Brayton cycle or combined cycle, to keep the plant idling. It will maintain the reaction conditions of the synthesis chamber and will not produce any ammonia. This is an important step as it takes days to reach the reaction conditions to start ammonia production again after shutting down due to unavailability of energy at low winds. Thus, at any windspeed, a mini-ammonia plant would either idle or operate between 65-100\% load. This model will be used to simulate the total energy consumption, total energy captured by the wind farm, and the total ammonia produced. This will further help in assessing the final cost of producing, transporting, and consuming ammonia as fuel and thereby provide a better understanding of the feasibility of implementing this technology

Chikungunya Fever: A Killer Epidemic in Ahmedabad City, India

Background The Chikungunya virus is an alphavirus native to tropical Africa and Asia and is transmitted to humans by the bite of infected Aedes mosquitoes. The symptoms of Chikungunya include sudden onset of fever, severe arthralgia, and maculopapular rash. Thirty percent of the population on the French R�union Island was afflicted with Chikungunya in the past year. They reported 237 deaths. India on the other hand reported 1.39 million cases of Chikungunya but no deaths. Methods Mortality data from 2002-2006 was obtained from the Ahmedabad Municipal Corporation (AMC). Actual mortality rate of 2006 was compared to the mortality rate of 2002-05 and its statistical significance tests were carried out. Findings Mortality data obtained from the Ahmedabad Municipal Corporation (AMC) suggests that 3112 excess deaths occurred in August-November (epidemic period) compared to the average deaths in the same months during the previous four years. These differences in deaths were found to be highly statistically significant. A peak in excess mortality is seen in the month of September when 1489 additional deaths were recorded. Case fatality rates for Ahmedabad also turn out to be much higher than that of the Reunion Island. Interpretation The Chikungunya epidemic was raging when the excess deaths occurred. There were no other adverse events or other epidemics that took place could explain this excess mortality. Government authorities, WHO and other international public health agencies should take these findings of excess mortality seriously and investigate into this occurrence of excess deaths to understand this reemerging disease and prevent future epidemics and mortality.

High magnetic field pulsars and magnetars: a unified picture

We propose a unified picture of high magnetic field radio pulsars and magnetars by arguing that they are all rotating high-field neutron stars, but have different orientations of their magnetic axes with respective to their rotation axes. In strong magnetic fields where photon splitting suppresses pair creation near the surface, the high-field pulsars can have active inner accelerators while the anomalous X-ray pulsars cannot. This can account for the very different observed emission characteristics of the anomalous X-ray pulsar 1E 2259+586 and the high field radio pulsar PSR J1814-1744. A predicted consequence of this picture is that radio pulsars having surface magnetic field greater than about $2\times 10^{14}$ G should not exist.Comment: 5 pages, emulateapj style, accepted for publication in the ApJ Letter

Comparative Evaluation of flank wear of uncoated, AlTiN and TiSiN Coated Cermet Insert by Machining of D2 Tool Steel

The life of a cutting tool is one of the major parameters which affects the cost and quality of machining. Hence manufacturing industries putting lots of effort and resources to increase tool life and productivity. This research focuses on increasing the life of cutting tool insert by suggesting new coating material for turning harden metals. An experimentation analysis is carried out on uncoated, conventional coated (AlTiN) and newly suggested coating (TiSiN) cermet insert. Experiments were carried out by selecting 90, 183, and 245 m/min as cutting speed, 0.2 mm/rev as feed, and 0.25 mm depth of cut. The result shows all three inserts give good performance at 90 m/min cutting speed. Tool life of AlTiN coated insert shows 20 min and TiSiN coated insert shows 22.21 min at 183 m/min cutting speed. At cutting speed 245 m/min all three types of cutting insert break even after 1 min of machining

First observations of the X-ray transient EXO 2030+375 with IBIS/ISGRI

We present a first INTEGRAL observation of the 42s transient X-ray pulsar EXO 2030+375 with IBIS/ISGRI. The source was detected during Cyg X-1 observations in December 2002. We analyzed observations during the outburst period from 9 to 21 December 2002 with a total exposure time of ~770 kiloseconds. EXO 2030+375 was almost always detected during single ~30 minute exposures in the 18-45 energy bands. The source light curve shows the characteristic outburst shape observed in this source.Comment: 4 pages, 3 figures (1 in CMYK color), accepted by Astronomy and Astrophysics, INTEGRAL special issue, 200

Milkweed blended fabrics and their thermal insulation and UV protection properties

Two sets of milkweed blended weft knitted fabrics have been produced and then tested for their constructional properties like courses/wales per inch, thickness, weight and tightness factor. These fabrics are also evaluated for thermal insulation (TI), water vapour permeability, air permeability and ultraviolet protection factor (UPF) properties and then compared with the only cotton and polyester knitted fabrics. The UPF and TI data of various blends of milkweed fibre with cotton or polyester have beed evaluated using one-way analysis of variance (ANOVA). Results reveal that the thermal insulation and ultraviolet protection factor of the milkweed blended fabric are higher than the corresponding properties of cotton and polyester fabrics, while the air permeability and water permeability properties are lower than the corresponding properties of cotton and polyester knitted fabrics.

An observational case control study: study of preterm labour- risk factors and its outcome

Background: Preterm birth is considered as the most significant risk in infant morbidity and mortality. The number of preterm births can be reduced significantly if all of the risk factors for predicting preterm births were eliminated to maximum extent. The aim of this study was analysis of risk factors of preterm labour and its outcome through case control study.Methods: It was an observational case control study of 200 pregnant women divided into study group of 100 pregnant women who were admitted with signs and symptoms of preterm labour with gestational age between 28-36 weeks. Control group of 100 pregnant women having gestational age above 36 weeks and with spontaneous onset of active labour. Risk factors and other parameters of both the groups were analyzed along with their neonatal outcome.Results: It was found that premature rupture of membrane, previous abortion, previous preterm delivery, anemia and impaired body mass index (BMI) are significantly higher in cases with preterm labour (p value <0.05). Hyperbilirubinemia, birth asphyxia and respiratory distress syndrome are significantly higher in cases with preterm labour (p value <0.05).Conclusions: Preterm labour is a multifactorial problem. Preterm labour and delivery require early and prolonged hospitalization causing great financial and psychological burden on the society and the number of preterm births can be reduced significantly if all of the risk factors for predicting preterm births were eliminated to maximum extent

Discovery of an X-ray pulsar in the low-mass X-ray binary 2A 1822-371

We report the discovery of 0.59 s X-ray pulsations from the low-mass X-ray binary, 5.57 hr dipping and eclipsing ADC source 2A 1822-371. Pulse arrival time analysis indicates a circular orbit with e < 0.03 (95% confidence) and an asini for the neutron star of 1.006(5) lightseconds, implying a mass function of (2.03+-0.03) x 10^-2 M_sun. The barycentric pulse period was 0.59325(2) s in 1996.270 and 0.59308615(5) s in 1998.205, indicating an average spin up with P_dot/P = (-1.52+-0.02) x 10^-4 yr^-1. For a magnetic field strength of ~1--5 x 10^12 G as derived from the X-ray spectrum the implied intrinsic X-ray luminosity is ~2-4 x 10^37 erg s^-1. The pulse amplitude is low, but increases steeply as a function of energy from a sinusoidal amplitude of 0.25% in 2-5.4 keV to ~3% above 20 keV. We discuss the constraints on the masses of the companion star and the fact that several aspects of the energy spectrum are in qualitative accordance with that of a strongly magnetised neutron star.Comment: 6 pages long, including 4 figures, uses emulateapj5, accepted for ApJL, Replaced figure

Histological evaluation of placenta in hypertensive pregnancies

Background: Maternal and fetal status are reflected in placenta. Toxemia of pregnancy exerts great impact on placenta and thereby fetal and maternal outcomes. Placenta reflects changes of toxemia and these changes are seen morphology as well as histology. Hence study of placenta gives information on the in-utero fetal condition.Methods: A total of 1000 placenta, 500 each from hypertensive and normotensive groups were included in this study conducted in Anatomy Department of SBKS Medical College and Research Centre, Vadodara. Histological evaluation of the samples taken was done under microscope.Results: Microscopic examination of the placenta revealed the presence of calcification, infarction, fibrinoid necrosis, villous hyalinization, syncytial knots and cytotrophoblastic cellular proliferation in both control and hypertension groups. In the present study, calcification was seen in 35.8% in the control group, while the same was seen in 53.8% patients in test group. Fibrinoid necrosis was seen in 48.8% patients in control group as against 69% patients in test group. Villous Hyalinization was seen in 7.40% and 21.4% patients in control and test groups respectively. On the other hand, syncytial knots were seen in 38% and 69% patients in control and test groups respectively. In test group, cytotrophoblastic cellular proliferation was seen in 69% patients while in control group, it was seen in 33.2% patients. Infarction was also seen in test (42.4%) and control (12.6%) groups.Conclusions: Hypertensive disorders of pregnancy have significant effect on the histology of placenta and also influences the fetal outcomes