Abstract  We report on new Suzaku and XMM-Newton results concerning HESS J1614-518, which is one of the brightest extended TeV gamma-ray sources and has two regions with intense gamma-ray emission. We newly observed the south and center regions of HESS J1614-518 with Suzaku, since the north region, including the position of the 1st brightest peak of the TeV gamma-ray emission, has already been observed. No X-ray counterpart was found at the position of the 2nd brightest peak of the TeV gamma-ray emission; we estimated the upper limit of the X-ray flux to be 1.6 x 10(-13) erg cm(-2) s(-1) in the 2-10 keV band. The soft X-ray source Suzaku J1614-5152, which was found at the edge of the field of view in a previous observation, was also detected at the middle of HESS J1614-518. Analyzing the XMM-Newton archival data, we revealed that Suzaku JI614-5152 consists of multiple point sources. The X-ray spectrum of the brightest point source, XMMU J161406.0-515225, can be described by a power-law model with a photon index of Gamma = 5.2(-0.5)(+0.6), or a blackbody model with temperature kT = 0.38(-0.04)(+0.04) keV. In the blackbody model, the hydrogen-equivalent column density is almost the same as that of the hard extended X-ray emission, Suzaku J1614-5141, which was found at the 1st peak position. If true, XMMU J161406.0-515225 may be physically related to Suzaku J1614-5141 and HESS J1614-518.

Abstract  In the recent times' fatty acid methyl ester popularly called as biodiesel has become more prominent alternate fuel for compression ignition engines based on a single fuel concept. Since. use of neat biodiesel on a large scale is raising certain difficulties and is being adopted in a blended form with petro-diesel fuel and B20 blend has become standardized. However, the HC and NO(x) emissions of B20 are still on the higher side. Present work aims at experimental evaluation of a single cylinder water-cooled diesel engine by adopting various proportions of ethanol and di ethyl ether blends in order to improve performance and emission characteristics of B20 blend. Besides employing different amounts of ethanol and di ethyl ether, simultaneous inluence of injector nozzle hole size and fuel injection pressure are also investigated to arrive at an optimum configuration. Brake specific fuel consumption and hydrocarbon emissions values are lower with B20 and DEE 5 whereas B20 with DEE 15 yielded lower NO(x) emissions. It is observed that addition of oxygenates have improved the combustion process and lower emissions are obtained. The present investigation revealed that blends with oxygenated additives having higher cetane rating are superior to neat blend.

Abstract  Clinical and experimental observations have supported the notion that free heme released during hemorrhagic and hemolytic episodes may have a major role in lung inflammation. With alveolar macrophages (AM) being the main line of defense in lung environments, the influence of free heme on AM activity and function was investigated. We observed that heme in a concentration range found during hemolytic episodes (3-30 μM) elicits AM to present a proinflammatory profile, stimulating reactive oxygen species (ROS) and nitric oxide (NO) generation and inducing IL-1β, IL-6, and IL-10 secretion. ROS production is NADPH oxidase-dependent, being inhibited by DPI and apocynin, and involves p47 subunit phosphorylation. Furthermore, heme induces NF- κB nuclear translocation, iNOS, and also HO-1 expression. Moreover, AM stimulated with free heme show enhanced phagocytic and bactericidal activities. Taken together, the data support a dual role for heme in the inflammatory response associated with lung hemorrhage, acting as a proinflammatory molecule that can either act as both an adjuvant of the innate immunity and as an amplifier of the inflammatory response, leading tissue injury. The understanding of heme effects on pulmonary inflammatory processes can lead to the development of new strategies to ameliorate tissue damage associated with hemorrhagic episodes.

Abstract  The Weather Research and Forecasting model coupled with chemistry, using 2 km horizontal grid spacing, is used to simulate two important relationships between aerosols and clouds in the vicinity of Oklahoma City during the June 2007 Cumulus Humilis Aerosol Processing Study (CHAPS). First, the model reproduces the trends of higher nitrate volume fractions in cloud droplet residuals compared to interstitial nonactivated aerosols, as measured using an aerosol mass spectrometer. Comparing simulations with cloud chemistry turned on and off, we show that nitric acid vapor uptake by cloud droplets explains the higher nitrate content of cloud droplet residuals. Second, the model reasonably represents the observations of the first aerosol indirect effect where pollutants in the vicinity of Oklahoma City increase cloud droplet number concentrations and decrease the droplet effective radius. In addition, as documented using an offline optical code, simulated aerosol optical properties depend on several compensating effects including aerosol water content, size-resolved chemical composition, and refractory index of various particle chemical species. All of our four sensitivity test cases clearly show an increase in simulated absorption and a decrease in single scattering albedo within the Oklahoma City plume relative to conditions outside the plume. While previous studies have often focused on cloud-aerosol interactions in stratiform and deep convective clouds, this study highlights the ability of regional-scale models to represent some of the important aspects of cloud-aerosol interactions associated with fields of short-lived shallow cumuli.

Abstract  Experimental studies have been carried out to investigate effects of biodiesel fuels on diesel engine performance, Carbon monoxide (CO) and nitric oxide (NOX) emissions, exhaust gas temperature (T-Exhaust), oil temperature (T-Oil), wall temperature (T-Wall), and cylinder pressure with/without exhaust gas recirculation (EGR). Biodiesel fuels are prepared from cotton seed oil, palm oil and flax oil. All the measured parameters for biodiesel fuels are compared with the base diesel fuel with/without EGR for different engine speeds. Fuel inlet temperature of 120 degrees C gives minimum viscosity different between diesel and biodiesel fuels. Biodiesel fuels give slightly less brake power (BP), brake thermal efficiency (eta(Bth)) and slightly high brake specific fuel consumption (BSFC) and high fuel mass flow rate per cycle. Diesel fuel gives CO higher than biodiesel fuels due to less O atoms in fuel molecules. Biodiesel fuels give NOX higher than diesel fuel due to high oxygen content in biodiesel fuels molecules and cetane number (CN). As EGR increases, CO increases while NOX decreases due to decrease flame temperature and O-2 in fresh air charge. For biodiesel fuels, T-Exhaust and T-Oil are higher than for diesel fuel. T-Wall for diesel fuel is higher than for all biodiesel fuels. Biodiesel fuels give peak cylinder pressure higher than diesel fuel. The position of peak cylinder pressure is arrangement as 11 crank angle degree (CAD) after top dead center (ATDC) for flax, 12 CAD ATDC for cotton, 14 CAD ATDC for palm and 20 CAD ATDC for diesel fuel respectively. The present work contributes in using biodiesel fuels as alternative fuel for diesel engines without major change for engines parts. For comparison between biodiesel and diesel fuels, the viscosity is not the main parameter affecting on engine performance and emissions. (C) 2013 Elsevier Ltd. All rights reserved.

Abstract  Upland oak forests in the ecotone between the eastern deciduous forest and the southern Great Plains are threatened by encroachment of eastern redcedar (Juniperus virginiana) due to fire suppression. The rapid rate of encroachment caused concern about concomitant alterations of site characteristics including nutrient cycling and the soil microbial communities (SMC) that could lead to positive feedbacks reinforcing eastern redcedar encroachment. We studied eight upland oak forests across central and western Oklahoma with stands representing three levels of encroachment: oak-dominated, eastern redcedar-dominated, and an intermediate mixture of both species. We analyzed litter chemistry (carbon, lignin, and nitrogen), soil chemistry (soil organic matter, NH4N, NO3-N, PO4, K, and pH), and profiled soil microbial communities using phospholipid fatty acid analysis (PLFA). Eastern redcedar encroachment was accompanied by reduced litter carbon along with higher levels of arbuscular mycorrhizal (AM) fungi while litter N was lower in mixed stands. However, we detected no change in soil chemistry. Our results indicate eastern redcedar encroachment in these upland oak forests reduced litter quality and altered the SMC through increases in AM fungi, a symbiont associated with eastern redcedar. These alterations may create positive soil-microbial feedbacks by reducing the fitness of the dominant oak species and facilitating rapid increase in eastern redcedar in this threatened, oak-dominated ecosystem. (C) 2013 Elsevier B.V. All rights reserved.

Abstract  Aiming at the harsh environmental situation at present, this paper applied the interval fuzzy linear programming method, and combines environmental management policy about the total control of regional atmospheric pollution, to set up an optimization model for total amount control of regional atmospheric pollutants under uncertainty. Through the model results, the total cost of reduction in instance case was [119.98, 125.82] (10(8) yuan), and the membership of SO2 and NOx predicted through the model were [31.00, 32.64] and [23.62, 25.94] (10(4) tons), respectively. This model could get the minimum total cost of emission reduction, and be used as the technique and theory guider for the total amount control of atmospheric pollutants.

Abstract  Wax crystallization characteristics, properties of viscosity-temperature and cold rheological properties of crude oil systems with different water cut are studied to analyze the feasibility and advantages of developing temperature drop gathering and transportation in Weixing Oilfield. On the basis of the characteristics of single pipe loop gathering and transportation technological process, an optimization mathematical model for oil gathering and transporting system operation is established, which objective function is the minimum energy consumption of the system. And to solve the model, the hierarchic optimization strategy is adopted. Optimization results of No.1 department and No.2 department showed that the water blending temperature is reduced more than 8 degrees C and the water blending amount is decreased 20%. According to the optimization scheme, the saving on gas and electricity are 7.12x10(5)m(3) and 8.92x10(5)kW-h each year.

Abstract  The rate constant for the gas phase reaction of OH radicals with BTP (2-bromo-3,3,3-trifluoropropene, CH2 = CBrCF3) was measured using a flash photolysis resonance-fluorescence technique over the temperature range 220 K to 370 K. The Arrhenius plot was found to exhibit noticeable curvature. The temperature dependence of the rate constant can be represented as k(BTP)(220 - 370 K) = 4.85 x 10(-13) x (T/298)(0.92) x exp{+613/T} cm(3) molecule(-1) s(-1). For atmospheric modeling purposes, k(BTP)(T) can be equally well represented by the standard Arrhenius expression k(BTP)(220 - 298 K) = 1.05 x 10(-12) x exp{+381/T} cm(3) molecule(-1) s(-1). The IR absorption cross-sections of BTP were also measured between 450 cm(-1) and 1900 cm(-1). BTP atmospheric lifetime, Ozone Depletion Potential (ODP), and Global Warming Potential (GWP) were evaluated in the Whole Atmosphere Community Climate Model for land emissions from 30 to 60 degrees N and from 60 degrees S to 60 degrees N. The global, annual average atmospheric lifetime of BTP in the former scenario was 7.0 days, its ODP was 0.0028, and its GWP (100-yr time horizon) was 0.0050; in the latter scenario, the global, annual average BTP lifetime was 4.3 days, ODP was 0.0052, and 100-yr GWP was 0.0028. The short lifetime, low ODP, and low GWP indicate that BTP should have minimal effects on ozone and climate. Little BTP reaches the stratosphere in either emission scenario, but 27% of the ozone loss in the 30 to 60 degrees N scenario and 46% of the ozone loss in the 60 degrees S to 60 N scenario occurs above the tropopause due to Br-y from BTP.

Abstract  The partitioning of reactive nitrogen (NOy) was measured over the remote North Pacific during spring 2006. Aircraft observations of NO, NO2, total peroxy nitrates (Sigma PNs), total alkyl and multi-functional nitrates (Sigma ANs) and nitric acid (HNO3), made between 25 degrees and 55 degrees N, confirm a controlling role for peroxyacyl nitrates in NOx production in aged Asian outflow. Sigma PNs account for more than 60% of NOy above 5 km, while thermal dissociation limits their contribution to less than 10% in the lower troposphere. Using simultaneous observations of NOx, Sigma PNs, Sigma ANs, HNO3 and average wind speed, we calculate the flux of reactive nitrogen through the meridional plane of 150 degrees W (between 20 degrees and 55 degrees N) to be 0.007 +/- 0.002 Tg N day(-1), which provides an upper limit of 23 +/- 6.5% on the transport efficiency of NOy from East Asia. Observations of NOx, and HOx are used to constrain a 0-D photochemical box model for the calculation of net photochemical ozone production or tendency (Delta O-3) as a function of aircraft altitude and NOx concentrations. The model analysis indicates that the photochemical environment of the lower troposphere (altitude < 6km) over the north Pacific is one of net O-3 destruction, with an experimentally determined crossover point between net O-3 destruction and net O-3 production of 60 pptv NOx. Qualitative indicators of integrated net O-3 production derived from simultaneous measurements of O-3 and light alkanes (Parrish et al., 1992), also indicate that the north Pacific is, on average, a region of net O-3 destruction.

Abstract  The influences of the springtime northern Indian biomass burning are shown for the first time over the central Himalayas by using three years (2007-2009) of surface and space based observations along with a radiative transfer model. Near-surface ozone, black carbon (BC), spectral aerosol optical depths (AODs) and the meteorological parameters are measured at a high altitude site Nainital (29.37 degrees N, 79.45 degrees E, 1958 m amsl) located in the central Himalayas. The satellite observations include the MODIS derived fire counts and AOD (0.55 mu m), and OMI derived tropospheric column NO2, ultraviolet aerosol index and single scattering albedo. MODIS fire counts and BC observations are used to identify the fire-impacted periods (372 h during 2007-2009) and hence the induced enhancements in surface BC, AOD (0.5 mu m) and ozone are estimated to be 1802 ng m(-3) (similar to 145%), 0.3 (similar to 150%) and 19 ppbv (similar to 34%) respectively. Large enhancements (53-100%) are also seen in the satellite derived parameters over a 2 degrees x 2 degrees region around Nainital. The present analysis highlights the northern Indian biomass burning induced cooling at the surface (-27 W m(-2)) and top of the atmosphere (-8 W m(-2)) in the lesser polluted high altitude regions of the central Himalayas. This cooling leads to an additional atmospheric warming of 19 W m(-2) and increases the lower atmospheric heating rate by 0.8 K day(-1). These biomass burning induced changes over the central Himalayan atmosphere during spring may also lead to enhanced short-wave absorption above clouds and might have an impact on the monsoonal rainfall.

Abstract  The present work focuses on the performance and emissions characteristics of a diesel engine operating on synthetic diesel fuel produced according to the Alphakat (KDV) technology. The purpose of the research was to examine the influence of the fuel of a new origin on the autoignition delay, cylinder gas pressure, brake thermal efficiency (bte), brake specific fuel consumption (bsfc) and emissions characteristics when running the engine on normal diesel fuel (OF) and KDV synthetic diesel fuel (SDF) over a wide range of loads and speeds. The bench tests were conducted on a naturally aspirated, four-stroke, four-cylinder, direct injection (60 kW) diesel engine D-243. When KDV synthetic diesel fuel was used the autoignition delay increased by 4.3 degrees crank angle degrees (CADS), the beginning of combustion occurred 4.2 degrees later and the maximum cylinder pressure increased by 1.8% compared to conventional diesel operation. The relative standard deviation (RSD) of p(max) was 3.5-1.4 times higher for corresponding loads at rated speed of 2200 rpm. The maximum brake thermal efficiency decreased by 1.6% and 4.0%, and the minimum bsfc values increased by 2.6% and 4.5% compared to the normal diesel running at respective 1400 and 2200 rpm speeds. The maximum NOx emissions were 3.0% and 12.8% higher when running on KDV fuel than those, 13.3 g/kW h and 10.9 g/kW h, generated by the normal diesel at speeds of 1400 and 2200 rpm. Respective ratios of the NO2/NOx were 4.6% and 4.0% for KDV synthetic fuel, and 4.8% and 2.9% for normal diesel fuel. The CO and HC emissions generated by KDV synthetic diesel fuel were 30.8% and 8.3% higher as against those, 2.6 g/kW h and 1.2 g/kW h, produced by the normal diesel running under full load at rated 2200 rpm speed. As beneficial trade off, KDV synthetic diesel fuel suggested the maximum smoke opacity 21.7% and 14.0% lower at respective speeds of 1400 and 2200 rpm. (C) 2012 Elsevier Ltd. All rights reserved.

Abstract  This study explores the appropriateness of the locality of air monitoring stations which are meant to indicate air quality in the area. Daily variations in NO(2) and PM(10) concentrations at fourteen monitoring stations in Hong Kong are examined. The daily variations in NO(2) at a number of background monitoring stations exhibit patterns similar to variations in traffic volume while variations in PM(10) concentration exhibit less discernible pattern. Principal Component Analysis (PCA) and Cluster Analysis (CA) are applied to analyse NO(2) and PM(10) measurements between January 2001 and December 2005. The results show that NO(2) concentrations at background stations within the urban area are highly influenced by vehicle emissions. The effect vehicle emission has on NO(2) at stations within new towns is smaller. CA results also show that variations in PM(10) concentrations are distinguished by the area the station is located in. The strong influence of roadside emissions towards concentrations of NO(2) and PM(10) at a number of urban background stations may be due to their close proximity to busy roadways and the high density of surrounding tall buildings, which creates an enclosure that hinders dispersion of roadside emissions and results in air pollution behaviour that reflects variation in traffic.

Abstract  In the present work, multiwalled carbon nanotubes were decorated with rhodium nanoparticles using a colloidal solution in the post-discharge of an RF atmospheric plasma of argon (Ar) or argon/oxygen (Ar:O(2)). The properties of these hybrid materials towards the room temperature detection of NO(2), C(2)H(4), CO, C(6)H(6) and moisture were investigated and discussed in view of compositional and morphological studies. It was found that the presence of oxygen in the plasma treatment is essential to significantly enhance the gas response of Rh-decorated multiwalled carbon nanotubes and to avoid response saturation even at low gas/vapor concentrations. These desirable effects are attributed to the presence of oxygen during the CNT plasma treatment since oxygenated vacancies act both as active adsorption sites for gases and as anchoring sites for Rh nanoparticles (the presence of Rh nanoclusters is nearly doubled in Ar:02 treated samples as compared to Ar treated samples). The oxygen treatment also makes easier the charge transfer between Rh nanoparticles and carbon nanotubes upon gas adsorption. The method for treating and decorating multiwalled carbon nanotubes used here is simple, fast and scalable for producing gas sensitive nanohybrid materials with uniform and well-controlled properties. (C) 2011 Elsevier B.V. All rights reserved.

Abstract  Three new silver (I) coordination complexes, [Ag-2(1,2-bdc)(phdat)](n) (1), [Ag-2(NO2-bdc)(phdat)](n) (2), [Ag-4 (nta)(3)(phdat)NO3](n) (3) (1,2-bdc=phthalic acid dianion, NO2-bdc=5-nitro-1,3-benzenedicarboxylic acid dianion, nta=nicotinic acid anion, phdat=2,4-diamine-6-phenyl-1,3,5-triazine) have been hydrothermally synthesized by the reactions of silver nitrate and phdat with the homologous ligands 1,2-H(2)bdc, NO2-H(2)bdc, and Hnta, respectively, and characterized by single-crystal X-ray diffractions, IR spectra, elemental analyses thermogravimetric analyses (TGA). The compound 1 exhibits a chiral 3D network with cbs/CrB self-dual topological net, which contains two kinds of single helical chains. For compound 2, the 3D network is comprised of two kinds of similar 2D sheets with the topological symbol of sql-type packed in AABBAA mode by Ag-N/O weakly contacts. And compound 3 has 2D double layer architecture, consisting of the 2D plane with hcb-type topological symbol connected by Ag-O weakly coordinations. The photoluminescent properties associated with the crystal structures of three compounds have also been measured. (C) 2013 Elsevier Inc. All rights reserved.

Abstract  A microsensor chip was fabricated by micro electromechanical system technology, and a portable electrochemical system for nitrate determination in freshwaters was developed. As the electrocatalyst material, copper was electrodeposited onto the working-electrode of the microsensor by the cyclic voltammetry method. It was found that the deposited layer was porous and constructed by copper nanoclusters. The electrochemical response of the modified microsensor for nitrate under acidic conditions (pH 2.0) was characterised by linear sweep voltammetry. Calibration in standard nitrate samples in the range of 6.25-300 mu mol/l yielded straight lines: y(1) [mu A] = -0.0526x-3.905 (R-1(2) = 0.9993), while in the range of 300-3500 mu mol/l yielded straight lines: y(2) [mu A] = -0.0353x-13.653 (R-2(2) = 0.9918). It was found that the modified microsensor performed at higher sensitivity in nitrate detection than previous works and the limit of detection is 5 mmol/l (S/N >= 3). Interference analysis with nine kinds of ions (NO2-, Cl-, HPO42/PO43, SO42, HCO3- /CO32, Na+ and K+) commonly found in water indicated that only NO2- causes reasonable interference (i.e. 10% signal distortion). Based on the modified microsensor, the developed portable electrochemical system was employed for nitrate determination in three freshwater samples. The results were in good agreement with the data obtained by the ultraviolet spectrophotometric method.

Abstract  This paper presents an investigation into the effect of biodiesel blending on emissions and efficiency in a stationary diesel engine. Rapeseed based biodicsel blended in increments of 25% with fossil diesel. The emissions of CO(2) show a decrease in emission (g/kWh) with increased engine load. Within the range of tests carried out, the NO(x) emissions from biodiesel and its blends proved to be higher than those of petro-diesel fuel. Furthermore, in this study a correlation was found relating the NO(x) emissions and the flame temperature. The efficiency of the system is improved with increased biodiesel content in the fuel. As predicted, the results for CLIP show a considerable improvement to the overall efficiency. [Received: January 22, 2011; Accepted: March 7, 2011]

Abstract  The purpose of this study is to clarify the fundamental and general features of N2O formation during the combustion of pulverized biomass under low temperature. First, the effect of various important factors, i.e., volatilization process (i.e., either slow or rapid dispersion), oxygen concentration, and solid-gas reaction on N2O formation were investigated by theoretical analysis. The analysis of the effect of the slow/rapid volatilization process on the formation of nitrous oxide showed that the conversion ratio of biomass-N to N2O increases with the decrease in the dispersion of volatile matter per unit time; it means that biomass-N is effectively converted to N2O during slow volatilization. The analysis of the effect of initial oxygen concentration on the formation of nitrous oxide showed that at low temperature (T=1100K), the level of N2O emission increases, while that of NO emission decreases, with the decrease in initial oxygen concentration. In other words, there is a trade-off relationship between the formation of NO and that of N2O. With respect to the effect of solid-gas reaction, the gasification reactions between CO2, O-2, and C(s) occur simultaneously on the surface of biomass particles during combustion. Further, the N2O emission level increases with the increase in N-content of the biomass, while the NO emission level remains constant during low-temperature combustion.

Abstract  Increasing energy demand and environment concerns have prompted an evolution of alternative fuel sources. As an alternative fuel source, biodiesel is attractive because it reduces engine emissions. However, biodiesel produces higher NOx emissions compared to ordinary diesel fuel. Previous researches have established many factors that cause biodiesel to produce elevated NOx emissions. This study reviews the impacts of biodiesel combustion on NOx emissions and their reduction approaches in diesel engines. The first part of this study recaps the NOx formation mechanisms for understanding the kinetics behind the NOx forming reactions. The second part describes the factors affecting on NOx emissions. This paper established that higher NOx emissions are produced for biodiesel combustion which influenced by several factors such as physicochemical properties and molecular structure of biodiesel, adiabatic flame temperature, ignition delay time, injection timing and engine load conditions etc. The final section discusses on the reduction of NOx emissions from biodiesel fuelled engines for both pre and post combustion techniques. The results of reduction approaches of the NOx emissions implies, exhaust gas recirculation (EGR) and retarded injection timing are effective as well as low cost techniques than others. Between these two techniques, EGR reduces the NOx emissions at 5-25% EGR rate adequately in biofuelled engine by controlling oxygen content and combustion peak temperature with slightly decreasing HC and CO emissions. However this technique shows few penalties on smoke and PM emissions as well as brake specific fuel consumption if not perfectly optimized. (C) 2013 Elsevier Ltd. All rights reserved.

Abstract  Annealing at high temperatures and exposure to strong ultra violet light are the approaches used in the past for affecting the desorption of strongly bound gases such as ammonia (NH3) and nitrogen dioxide (NO2) from single wall carbon nanotubes (SWCNTs) and graphene. These methods pose severe limitations in the development of devices which can operate in normal ambient conditions. The use of another gas which can influence the kinetics of desorption of gases already present on the SWCNTs has not been explored in detail. Here we show that the redistribution of substrate impurity states near Fermi Level, caused by the electrostatic forces of polar molecules like water, accelerates the desorption of gases bound on SWCNT. This phenomenon can be used to facilitate complete, rapid and non-destructive desorption of NO2 and NH3 molecules from SWCNT chemiresistors at room temperature. Complete desorption of these gases were achieved within minutes instead of many hours as reported previously in the literature. The method provides a practical alternative for achieving recovery in CNT-based molecule detectors in air without the risk of degradation of the SWCNTs and their sensitive polymer composites which are used to achieve high sensitivity and selectivity. (C) 2013 Elsevier Ltd. All rights reserved.

Abstract  The mixing of fuel and oxidizer is critical for the reduction of NOx emissions from premixed combustion burners. The mixing process in a pre-mixer of a natural gas-fired conical wire-mesh duct burner (DB) was studied experimentally using the laser sheet illumination (LSI) technique. A quasi-quantitative technique was used to rank the relative mixing performance of the different geometrical and flow combinations tested (mixer geometry, fuel injection angle and fuel air momentum ratio).The present paper presents some of the results used in the design and analysis of the burner. This burner was integrated and tested with a micro-turbine cogeneration system (MT70 kW Ingersoll Rand (IR) CHP unit). The DB provides supplementary firing in the exhaust gas stream of the micro-turbine to increase and control the thermal output of the micro-cogeneration system. The combination provided near perfect premixing and low emissions. The DB successfully raised the micro-turbine exhaust gas temperature from about 227 degrees C to as high as 700 degrees C with NOx and CO emissions of less than 5 ppm and 10 ppmv (corrected to 15 percent O-2) respectively. The DB also displayed stable, low emissions operation throughout the surface firing rate range of 148 kW to 328 kW (1574 kW/m(2) to 3489 kw/m(2)). The results show that LSI technique can provide invaluable information about the overall flow field structure. Many important observations are discussed such as mixing, fuel spread, and fuel jet penetration. Samples of the LSI images and 3D plots for selected cases are presented. The two best geometrical combinations ranked during the LSI test were used in the actual combustion test of the DB. Some of the combustion results which prove the effectiveness of the LSI technique are presented.

Abstract  The fate of N-15-labeled potassium nitrate (8.5% N-15 excess) was determined in 3-year-old Valencia orange trees grown in 1-m(3) containers filled with different textured soils (sandy and loamy). The trees were fertilized either in spring (24 March) or summer (24 July). Spring fertilized trees gave higher fruit yields in sandy than in loamy soils, which exceeded summer fertilized trees in both cases. Summer fertilized trees had greater leaf biomass than spring fertilized trees. Fibrous root weight was 1.9-fold higher in sandy than in loamy soil. At the end of the cycle, tree N recovery from spring application was 45.7% for sandy and 37.7% for loamy soil; from summer fertilization, N recovery was 58.9% and 51.5% for sandy and loamy soils, respectively. The N-15 recovered in the inorganic soil fraction (0-90 cm) was higher for loamy (1.3%) than for sandy soil (0.4%). Fertilizer N immobilized in the organic matter was lower in sandy (2.5%) than in loamy soil (6.0%). Potential nitrate leaching from fertilizer ((NO)-N-15 (3) (-) -N in the 90-110-cm soil layer plus (NO)-N-15 (3) (-) -N in drainage water) was 34.8% higher in sandy than in loamy soil. The low N levels in sandy soil resulted from both higher NO (3) (-) -N leaching losses and higher N uptake of plants grown in the former. The great root mass and higher soil temperatures could account for raised plant N uptake in sandy soil and in summer, respectively.

Abstract  The UNECE-ICP Integrated Monitoring site Zobelboden in the Northern Alps of Austria was established to assess the effects of air pollutants on forest ecosystems. Changes in recruitment of the dominant tree species may be among these effects but there is little information on how germination and juvenile growth of these species respond to changes in nutrient supply. This study focused on the effects of nitrogen availability on the performance of the early life history stages of Picea abies, Fagus sylvatica, Fraxinus excelsior and Acer pseudoplatanus based on measured soil variables and Ellenberg indicator values. For 106, 0.5 x 0.5 m plots, the pH-value, NH4+, NO3-, gross and net N mineralization and C:N ratio of the top mineral soil were analyzed. Additionally, incoming solar radiation and estimated number of seeds arriving in each plot were recorded. Recruitment and juvenile growth rates of the tree species were related to these variables and to mean Ellenberg indicator values calculated from the vascular plant species composition of the plots, respectively, using linear or generalized linear mixed models. Despite the relatively high correlations of Ellenberg indicator values with the three measured soil variables, namely pH, ammonium, and, in particular, gross N mineralization, models using measured variables and Ellenberg indicator values produced inconsistent results in most cases. In general, closer correlations were obtained between measured soil variables and tree performance than between Ellenberg indicator values and tree performance. Measured nitrogen variables had a significant effect on the recruitment and growth of Fagus sylvatica and Acer pseudoplatanus. However, whereas the growth of both species was similarly greater where NH4 contents and gross mineralization rates were higher, their responses to soil nitrogen were clearly distinct in terms of recruitment. Finally, neither recruitment nor growth of Fraxinus excelsior are significantly correlated with any of the measured nitrogen variables. Partitioning of regeneration niches in terms of different nitrogen sources and supply rates might hence contribute to the co-existence of different tree species in such mixed mountain forests.

Abstract  Background: Intermittent PTH administration directly stimulates osteoblasts; however, mechanisms of bone accrual that are independent of the direct actions on osteoblasts may be under-appreciated. Our aims were to decipher (1) whether PTH 1-84 augments vasodilation of the femoral principal nutrient artery (PNA), (2) whether 15 days of intermittent PTH 1-84 augments endothelium-dependent and/or -independent vasodilation of the femoral PNA, and (3) the signaling mechanisms involved. Methods: Experiment 1: Femoral PNAs from male Wistar rats were exposed to cumulative doses of PTH 1-84 with and without an anti-vascular endothelial growth factor antibody and/or the endothelial NO synthase inhibitor L-NAME. Experiment 2: Male Wistar rats were administered PTH and/or the anti-VEGF antibody for 2 weeks. Subsequently, endothelium-dependent vasodilation to acetylcholine and endothelium-independent vasodilation to sodium nitroprusside were assessed. In addition, endothelium-dependent signaling pathways were analyzed by use of t-NAME and/or and the cyclooxygenase inhibitor indomethacin. Results: Cumulative doses of PTH 1-84 induced vasodilation of the femoral PNA, which was reduced by and 87% with the anti-VEGF antibody and I.-NAME, respectively, Secondly, 2 weeks of intermittent PTH 1-84 administration doubled trabecular bone volume, augmented bone formation parameters and reduced osteoclast activity. In addition, PTH enhanced endothelium-dependent vasodilation via up-regulation of NO. Co-administration of the anti-VEGF antibody (1) inhibited the PTH-induced increase in bone volume and remodeling parameters and (2) blunted the augmented vasodilator responsiveness of the PNA. Finally, endothelium-dependent vasodilation in PTH-treated rats was highly correlated with trabecular bone volume. Conclusion: As hypothesized, PTH enhanced endothelium-dependent vasodilation of the femoral PNA via augmented NO production and was mediated partially through VEGF signaling. Further, vasodilation to PTH appears independent of vascular smooth muscle cell participation. More importantly, the strong association between vasodilation and bone volume suggests that bone arteriolar function is critical for PTH-induced bone anabolism. Published by Elsevier Inc,