Reduction In Ambient Temperature Research Articles

Numerical investigation of cooling performance of a novel air-cooled thermal management system for cylindrical Li-ion battery module

Batteries strongly influence the performance of electric vehicles. Therefore it is crucial to develop a battery thermal system that is highly efficient in removing the battery pack's heat during its operation. In this paper, a numerical analysis of a lumped thermal model coupled with fluid flow equations is employed to investigate the novel air-cooled battery thermal management system (BTMS). The cooling efficiency of the proposed battery thermal system with commercial thermal interface material (3M™) is investigated by comparing it with a standard battery pack at different discharge rates. The proposed solution offers a 25% reduction in peak temperature when compared to the standard one. The thickness of the thermal interface material is found to have an insignificant impact on the battery pack's thermal performance. Introducing forced air-cooling in the battery pack reduced the maximum temperature considerably but increased the temperature difference compared to the battery pack without forced convection. Then the effect of various structural and operational parameters on the performance of the BTMS is investigated. Moving the air inlet-outlet boundaries to a central location increased the uniformity of temperature distribution in the battery pack. Although the increase in the inlet airflow velocity reduces the maximum temperature, it comes at the cost of an increase in temperature difference and power consumption. It is further observed that a reduction in ambient temperature reduces the peak temperature and makes the temperature distribution in the battery pack more homogeneous. The discharge voltage curves indicate a slight reduction in cell potential as a reducing function of temperature.

On the cooling potential of urban heating mitigation technologies in a coastal temperate city

We assess the impact of advanced heat-mitigation technologies in a coastal temperate city under heatwave conditions. For the first time urban-heating mitigation scenarios that refer to ‘cool/reflective’ roofs and roads, ‘green/living’ roofs and shading by replacing low urban vegetation with deciduous broadleaf trees are considered at the highly dense-populated city of Athens (Greece). Numerical simulations are performed for a typical see-breeze and a heatwave day with the Weather Research and Forecasting (WRF) model coupled to an urban-canopy model. Highresolution data on vegetation and urban land use, derived from satellite image analysis, are considered. All scenarios show a cooling effect, with the maximum mean daytime temperature reduction in the case of ‘cool/reflective’ roofs and roads. During daytime, the mean ambient-temperature reduction reaches up to 1 °C while for the surface-temperature up to 9.5 °C and 11.5 °C, on the see-breeze and heatwave day respectively. In the case of ‘green/living’ roofs, the mean daytime latent-heat flux is increased (e.g. up to 140 W/m2 on the heatwave day) due to increased evapotranspiration while the surface temperature is more affected during nighttime. Both scenarios result in a sea-breeze attenuation of 0.5–1 m/s. The presence of deciduous broadleaf street trees has a minor impact on mean ambient temperature but an evident reduction in surface temperature. The mean urban-heating reduction ranges from 0.1 °C to 0.8 °C and from 0.3 °C to 1.7 °C during the sea breeze and heatwave day respectively, with the maximum reduction shown in ‘cool/reflective’ roofs and roads and the minimum in ‘shading trees’ scenarios.

A time series analysis of the relationship between ambient temperature and ischaemic stroke in the Ljubljana area: immediate, delayed and cumulative effects

BackgroundStroke is a major health problem around the world. Several studies have examine the influence of ambient temperature on incidence of stoke, but they reported different results for different types of stroke and different geographical regions. Hence, effect of ambient temperature is still much of interest, when focusing on ischemic stroke (IS) in regions that have not been examined yet. The aim of our study is to analyse association between IS incidences and short, delayed and cumulative effect of average daily ambient temperature, humidity and pressure in central Europe. To the best of our knowledge, this is the first IS study conducted between 45° and 50° latitude where large part of Central European population resides.MethodsWe linked daily hospitals’ admission data for whole population and separately for two specific age groups with ambient temperature data. We considered patients coming from Ljubljana basin and its immediate surrounding. Data were gathered daily from January 2012 to December 2017. To measure the effect of average ambient temperature, humidity and pressure we used generalized linear model with a log-link-function and a Poisson distribution.ResultsThe results of our study show a statistically significant immediate, delayed and cumulative effects of ambient temperatures on IS incidence for the whole population and the population older than 65 years. Specifically, 1 °C reduction in ambient temperature on a given day (Lag 0) increases the IS risk for approximately 5‰ (all population) or 6‰ (population older than 65 years). Similar effects were found for lags from 1 to 6. Analysis of time windows from 0 to 1 days up to 0–28 days also show statistically significant cumulative effect for the same two age groups. IS incidence was not found to be significantly related to pressure or humidity in any group.ConclusionThe findings of this study may help healthcare authorities in central Europe improve existing stroke prevention measures and raise public awareness.

Impact of ambient temperature on inflammation-induced encephalopathy in endotoxemic mice\u2014role of phosphoinositide 3-kinase gamma

BackgroundSepsis-associated encephalopathy (SAE) is an early and frequent event of infection-induced systemic inflammatory response syndrome. Phosphoinositide 3-kinase γ (PI3Kγ) is linked to neuroinflammation and inflammation-related microglial activity. In homeotherms, variations in ambient temperature (Ta) outside the thermoneutral zone lead to thermoregulatory responses, mainly driven by a gradually increasing sympathetic activity, and may affect disease severity. We hypothesized that thermoregulatory response to hypothermia (reduced Ta) aggravates SAE in PI3Kγ-dependent manner.MethodsExperiments were performed in wild-type, PI3Kγ knockout, and PI3Kγ kinase-dead mice, which were kept at neutral (30 ± 0.5 °C) or moderately lowered (26 ± 0.5 °C) Ta. Mice were exposed to lipopolysaccharide (LPS, 10 μg/g, from Escherichia coli serotype 055:B5, single intraperitoneal injection)—evoked systemic inflammatory response (SIR) and monitored 24 h for thermoregulatory response and blood–brain barrier integrity. Primary microglial cells and brain tissue derived from treated mice were analyzed for inflammatory responses and related cell functions. Comparisons between groups were made with one-way or two-way analysis of variance, as appropriate. Post hoc comparisons were made with the Holm–Sidak test or t tests with Bonferroni’s correction for adjustments of multiple comparisons. Data not following normal distribution was tested with Kruskal-Wallis test followed by Dunn’s multiple comparisons test.ResultsWe show that a moderate reduction of ambient temperature triggers enhanced hypothermia of mice undergoing LPS-induced systemic inflammation by aggravated SAE. PI3Kγ deficiency enhances blood–brain barrier injury and upregulation of matrix metalloproteinases (MMPs) as well as an impaired microglial phagocytic activity.ConclusionsThermoregulatory adaptation in response to ambient temperatures below the thermoneutral range exacerbates LPS-induced blood–brain barrier injury and neuroinflammation. PI3Kγ serves a protective role in suppressing release of MMPs, maintaining microglial motility and reinforcing phagocytosis leading to improved brain tissue integrity. Thus, preclinical research targeting severe brain inflammation responses is seriously biased when basic physiological prerequisites of mammal species such as preferred ambient temperature are ignored.

Methane and carbon dioxide emissions from yearling beef heifers and mature cows classified for residual feed intake under drylot conditions

This study quantified methane (CH4) and carbon dioxide (CO2) production from beef heifers and cows classified for residual feed intake adjusted for off-test backfat thickness (RFIfat) and reared in drylot during cold winter temperatures. Individual performance, daily feed intake, and RFIfat were obtained for 1068 crossbred and purebred yearling heifers (eight trials) as well as 176 crossbred mature cows (six trials) during the winters of 2015–2017 at two locations. A portion of these heifers (147 high RFIfat; 167 low RFIfat) and cows (69 high RFIfat; 70 low RFIfat) was monitored for enteric CH4 and CO2 emissions using the GreenFeed Emissions Monitoring (GEM) system (C-Lock Inc., Rapid City, SD, USA). Low RFIfat cattle consumed less feed [heifers, 7.80 vs. 8.48 kg dry matter (DM) d−1; cows, 11.64 vs. 13.16 kg DM d−1] and emitted less daily CH4 (2.5% for heifers; 3.7% for cows) and CO2 (1.4% for heifers; 3.4% for cows) compared with high RFIfat cattle. However, low RFIfat heifers and cows had higher CH4 (6.2% for heifers; 9.9% for cows) and CO2 yield (7.3% for heifers; 9.8% for cows) per kilogram DM intake compared with their high RFIfat pen mates. The GEM system performed at air temperatures between +20 and −30 °C. Feed intake of heifers and mature cows was differently affected by ambient temperature reduction between +20 and −15 °C and similarly increased their feed intake at temperatures below −15 °C. In conclusion, low RFIfat animals emit less daily enteric CH4 and CO2, due mainly to lower feed consumption at equal body weight, gain, and fatness.

Impact of urban heat island mitigation measures on microclimate and pedestrian comfort in a dense urban district of Lebanon

The interaction between microclimate and buildings is predominant in urban areas. Thus, the urbanization constitutes the main cause of UHI formation. During the last years, several studies exposed the critical effects of UHI in the Mediterranean climate. As a result, there is a need for sustainable systems and urban policies to reduce heat islands in urban areas. This paper aims to present the impact of some UHI mitigation strategies in a Mediterranean city, Beirut Lebanon. Numerical microclimate simulations of an existing Lebanese district of Dora in Beirut, are performed using ENVI-met software. The study focuses on the potential of UHI mitigation scenarios to create freshness in summer conditions. The strategies are based on the increase of green surfaces, on the installation of water spray and fountains, and on the increase of the albedo of the facades and roofs of the buildings. A focus is carried out on white models, dealing with the albedo modification of roads and buildings. The effect of the proposed strategies on the pedestrian comfort is also evaluated by using the physiologically equivalent temperature PET. Results pointed out that implementation of water features contributes to a significant reduction of ambient temperature reaching a maximum of 5 °C. In term of outdoor thermal comfort, the results showed the important role of green areas on the improvement of pedestrian comfort during daytime. Finally, this research supports a set of actions that could be helpful for urban designer to create cool islands in the Lebanese neighborhoods.

Improvement of diesel engine startability under low temperatures by vortex tubes

Cold start is one of the most problematic combustion phases for diesel engines. During this phase, a large proportion of pollutants are produced within the cylinder due to misfiring and incomplete combustion due to the low engine temperatures. Furthermore, exhaust after-treatment devices work inefficiently since their minimum operation temperatures cannot be reached. In addition to this, at temperatures below 0 °C the possibility of continuous misfiring could actually impede the engine start. Ambient temperature is one of the most important factors affecting the diesel engine cold startability.The aim of this study is to improve diesel engine startability under low temperatures by vortex tubes. A vortex tube was used to increase the intake air temperature in a six cylinders, four stroke and direct injection diesel engine of a truck. The hot air obtained from the hot outlet of the vortex tube was mixed with the air coming from the inlet of the intake manifold and the warmer air was sent to the cylinders. The compressed air required for the operation of the vortex tube was provided from the air tank of the compressed-air brake system of the truck. The effects of variation in ambient temperature on the engine cranking speed and in-cylinder pressure were analyzed and presented. Experiments were conducted for ambient air temperatures of −5, 0 and +4 °C. It was found that the reduction in ambient temperature resulted in prolonged cranking periods along with the longer time taken to reach idling speed as well as increased combustion instability for the engine without vortex tube. The use of the vortex tube increased the intake air temperature, which decreased durations of engine starting–cranking, cranking–idling, and idling–stabling. These results indicate that the cold starting performance of the diesel engine could be improved by using vortex tubes.

Experimental study of the influence of the fuel and boundary conditions over the soot formation in multi-hole diesel injectors using high-speed color diffused back-illumination technique

Two prototypes multi-hole diesel injector from a high-pressure common rail system were used to operated with diesel and n-Heptane fuels in a high-pressure and high-temperature test rig able to reach 1100 K and 15 MPa under different oxygen concentrations with the goal to study the influence of the boundary conditions on the combustion process evaluating parameters as ignition delay, lift-off length and soot formation. A novel optical set-up was implemented to visualize the soot cloud evolution in the fuel jet between 30 and 85 mm from the nozzle exit using the high-speed color diffused back-illumination technique, it was used as a result of the insertion of a high-pressure window in the injector holder opposite to the frontal window of the vessel allowing an optical arrangement in line-of-sight. The experiments performed in this work used a LED with a wavelength of 460 nm to provide information about physical of the soot properties, the results of varying the operational conditions show the reduction of soot formation with an increase in injection pressure, a reduction in ambient temperature, a reduction in oxygen concentration or a reduction in ambient density. Furthermore, fuel effect on soot formation also has been studied showing a big difference between both fuels, diesel is known to be more prone to produce soot than n-Heptane reducing the ability of the technique implemented, especially in conditions with high temperature and high density.

Three physiological parameters capture variation in leaf respiration of Eucalyptus grandis, as elicited by short-term changes in ambient temperature, and differing nitrogen supply.

We used instantaneous temperature responses of CO2 -respiration to explore temperature acclimation dynamics for Eucalyptus grandis grown with differing nitrogen supply. A reduction in ambient temperature from 23 to 19°C reduced light-saturated photosynthesis by 25% but increased respiratory capacity by 30%. Changes in respiratory capacity were not reversed after temperatures were subsequently increased to 27°C. Temperature sensitivity of respiration measured at prevalent ambient temperature varied little between temperature treatments but was significantly reduced from ~105kJmol-1 when supply of N was weak, to ~70kJmol-1 when it was strong. Temperature sensitivity of respiration measured across a broader temperature range (20-40°C) could be fully described by 2 exponent parameters of an Arrhenius-type model (i.e., activation energy of respiration at low reference temperature and a parameter describing the temperature dependence of activation energy). These 2 parameters were strongly correlated, statistically explaining 74% of observed variation. Residual variation was linked to treatment-induced changes in respiration at low reference temperature or respiratory capacity. Leaf contents of starch and soluble sugars suggest that respiratory capacity varies with source-sink imbalances in carbohydrate utilization, which in combination with shifts in carbon-flux mode, serve to maintain homeostasis of respiratory temperature sensitivity at prevalent growth temperature.

Assessing Vulnerability to Heat: A Geospatial Analysis for the City of Philadelphia

Urban heat island (UHI) effect is an increasingly prominent health and environmental hazard that is linked to urbanization and climate change. Greening reduces the negative impacts of UHI; trees specifically are the most effective in ambient temperature reduction. This paper investigates vulnerability to heat in the Philadelphia, Pennsylvania and identifies where street trees can be planted as a public intervention. We used geospatial information systems (GIS) software to map a validated Heat Vulnerability Index to identify vulnerability at the block level. Using a high-low geospatial cluster analysis, we assessed where the City of Philadelphia can most effectively plant street trees to address UHI. This information was then aggregated to the neighborhood level for more effective citizen communication and policymaking. We identified that 26 of 48 (54%) neighborhoods that were vulnerable to heat also lacked street trees. Of 158 Philadelphia neighborhoods, 63 (40%) contained block groups of high vulnerability to either heat or street tree infrastructure. Neighborhoods that were ranked highest in both classifications were identified in two adjacent West Philadelphia neighborhoods. Planting street trees is a public service a city can potentially reduce the negative health impacts of UHI. GIS can be used to identify and recommend street tree plantings to reduce urban heat.

Warming Induces Significant Reprogramming of Beige, but Not Brown, Adipocyte Cellular Identity

Beige and brown adipocytes generate heat in response to reductions in ambient temperature. When warmed, both beige and brown adipocytes exhibit morphological "whitening," but it is unknown whether or to what extent this represents a true shiftin cellular identity. Using cell-type-specific profiling invivo, we uncover a unique paradigm of temperature-dependent epigenomic plasticity of beige, but not brown, adipocytes, with conversion from a brown to a white chromatin state. Despite this profound shift in cellular identity, warm whitened beige adipocytes retain an epigenomic memory of prior cold exposure defined by an array of poised enhancers that prime thermogenic genes for rapid response during a second bout of cold exposure. We further show that a transcriptional cascade involving glucocorticoid receptor and Zfp423 can drive warm-induced whitening of beige adipocytes. These studies identify the epigenomic and transcriptional bases of an extraordinary example of cellular plasticity in response to environmental signals.

Global Analysis of Plasma Lipids Identifies Liver-Derived Acylcarnitines as a Fuel Source for Brown Fat Thermogenesis

Cold-induced thermogenesis is an energy-demanding process that protects endotherms against a reduction in ambient temperature. Using non-targeted liquid chromatography-mass spectrometry-based lipidomics, we identified elevated levels of plasma acylcarnitines in response to the cold. We found that the liver undergoes a metabolic switch to provide fuel for brown fat thermogenesis by producing acylcarnitines. Cold stimulates white adipocytes to release free fatty acids that activate the nuclear receptor HNF4α, which is required for acylcarnitine production in the liver and adaptive thermogenesis. Once in circulation, acylcarnitines are transported to brown adipose tissue, while uptake into white adipose tissue and liver is blocked. Finally, a bolus of L-carnitine or palmitoylcarnitine rescues the cold sensitivity seen with aging. Our data highlight an elegant mechanism whereby white adipose tissue provides long-chain fatty acids for hepatic carnitilation to generate plasma acylcarnitines as a fuel source for peripheral tissues in mice.

Performance Evaluation of Paving Blocks Based Ambient Temperature Reduction Using a Climatic Environment Chamber

본 연구는 보도, 차도, 주차장, 공원, 광장 등에서 많이 사용되고 있는 포장 재료인 블록의 증발 등 열적 성능을 평가하였다. 일반적으로 많이 사용되고 있는 일반블록과 LID (Low Impact Development)형 제품인 투수블록과 보수블록을 비교하였으며, 통제된 기후조건 (일사, 강우, 강설, 온도, 습도 등)이 갖춰진 챔버 (ch...

The performance of three fog gauges under field conditions and its relationship with meteorological variables in an exposed site in Tenerife (Canary Islands)

We characterized the fog phenomena and associated micrometeorological variables in a 1093m a.s.l. site in Tenerife (Canary Islands) during a 42 months period with three different fog gauges. Fog was more frequent during night-time and early morning, concomitantly with a reduction in ambient temperature and an increase in wind velocity (u). Furthermore, diurnal hourly medians of both reference evapotranspiration (r2≥0.75) and net radiation (r2≥0.95) were linearly correlated during foggy versus fog free conditions. Such correlations were different depending on whether fog was light (i.e. visibility, Ω>200m) or dense (Ω<200m). Although the actual gauge’s fog water collection (FWC) depends on many concurrent factors and it is nonlinearly related to the micrometeorological variables, thus difficult to predict, the curves fitting the maxima of FWC vs. Ω and FWC vs. u data were shown to be a good descriptor of the fog water collection potential of the site. Some bounds were established on such envelope curves during strong wind gusts in terms of the force balance that lead to re-entrainment and clogging of a particular gauge screen by water drops with different geometry. The results presented advance on the possibility of relating ground base local measurements of fog water yield with the remote monitoring of auxiliary meteorological variables, such as the visibility, in order to characterize broad areas for their fog water harvesting potential, either for its exploitation or its effect on cloud immersed forests.

Fluctuation in ambient temperature: interplay between brown adipose tissue, metabolic health, and cardiovascular diseases

The variations in ambient temperature have been associated with high occurrence of cardiovascular diseases, which is one of the leading global risks for the mortality accounting for 50% of the death in the developed countries. Both heat- and cold-related excess mortalities are mostly attributable to the increase in cardiovascular diseases. Due to the loss of climate system balance caused by increased atmospheric concentration of greenhouse gases, the average global temperatures are expected to rise by 1.1–6.4°C from 1990 to the end of the 21 st century. The reinforced intensity, duration, and frequency of heat waves were observed in the past decade with increased average atmosphere and ocean temperature on the Earth. The positive relationship between the heat wave and cardiovascular mortality and morbidity has been demonstrated in the areas with either lower or higher average temperatures. That is, to say, the sudden extreme heat condition lays stress on the cardiovascular system in humans. With a growing body of epidemiological studies, extreme temperature environments and cardiovascular conditions have been increasingly associated. As a class of chronic disorders, the initiation and development of cardiovascular diseases were mainly attributed to metabolic disorders reflecting the prolong stress from obesity, hypertension, hyperglycemia, and hypercholesterolemia whereas the stimulus of sudden temperature change was thought to trigger the onset or worsening of major cardiovascular diseases, which were established by these cumulative risk factors. However, the cold temperature exposure has recently been regarded as a novel therapeutic approach to defense against cardiovascular diseases such as obesity which is resulted from the imbalance between energy intake and energy expenditure. With the chronic mild reduction of ambient temperature, the prevalence and activity of brown adipose tissue (BAT) were upregulated, and the BAT-mediated thermogenesis helps the individual to correct the deviation of energy balance from excess white adipose tissue accumulations. The aim of the present paper was to systematically review the positive and negative effects of the ambient temperature change on cardiovascular diseases, which may lead to new intervention to metabolic health and cardiovascular disease prevention.

Ambient temperature reduction extends lifespan via activating cellular degradation activity in an annual fish (Nothobranchius rachovii).

Ambient temperature reduction (ATR) can extend the lifespan of organisms, but the underlying mechanism is poorly understood. In this study, cellular degradation activity was evaluated in the muscle of an annual fish (Nothobranchius rachovii) reared under high (30°C), moderate (25°C), and low (20°C) ambient temperatures. The results showed the following: (i) the activity of the 20S proteasome and the expression of polyubiquitin aggregates increased with ATR, whereas 20S proteasome expression did not change; (ii) the expression of microtubule-associated protein 1 light chain 3-II (LC3-II) increased with ATR; (iii) the expression of lysosome-associated membrane protein type 2a (Lamp 2a) increased with ATR, whereas the expression of the 70-kD heat shock cognate protein (Hsc 70) decreased with ATR; (iv) lysosome activity increased with ATR, whereas the expression of lysosome-associated membrane protein type 1 (Lamp 1) did not change with ATR; and (v) the expression of molecular target of rapamycin (mTOR) and phosphorylated mTOR (p-mTOR) as well as the p-mTOR/mTOR ratio did not change with ATR. These findings indicate that ATR activates cellular degradation activity, constituting part of the mechanism underlying the longevity-promoting effects of ATR in N. rachovii.

Spray and Combustion Characteristics of Neat Acetone-Butanol-Ethanol, n-Butanol, and Diesel in a Constant Volume Chamber

Intermediate product of biobutanol production, acetone-butanol-ethanol (ABE) as an alternative fuel has drawn increasing attention in recent years due to its potential to eliminate various production costs. In this work, neat acetone-butanol-ethanol (ABE) with a component volumetric ratio of 3:6:1, n-butanol, and neat diesel were studied in a preburn type constant volume chamber with optical access. The ambient temperature and oxygen ranged from 800 to 1200 K and 21% to 11%, respectively, covering both conventional and low temperature combustion (LTC) regimes. Time resolved images of the spray and natural flame luminosity (indicator of soot) were captured by a high speed camera coupled with a copper vapor laser beam. The images show that the flame lift-off length and liquid penetration of n-butanol and ABE are much longer and shorter, respectively, than that of diesel under all tested conditions. This results in a longer “gap” between the liquid spray and the flame in ABE and n-butanol combustion that provides more space and time for the droplets to evaporate and mix with the ambient air, which is expected to decrease the local equivalence ratio at the combustion region. Indeed, the natural flame luminosity of ABE and n-butanol is reduced significantly under all tested conditions compared to that of diesel. For all the tested fuels, especially ABE, the combustion duration decreases with the reduction of ambient temperature due to a stronger premixed combustion, while it increases with the reduction of oxygen concentration due to the dilution effect. Therefore, ABE has a high potential to reduce soot emissions when used in diesel engines, but it would also suffer from combustion phasing retardation like butanol under LTC conditions with high EGR.

Thermal Analysis of Semicircular Fins Considering Temperature-dependent Thermal Conductivity and Heat Transfer Coefficient

This paper investigates the semicircular fin efficiency considering the fact that both thermal conductivity of the fin material and the heat transfer coefficient for dissipation of heat from the fin surface are temperature dependent and can render changes in fin efficiency for large temperature differences. Based on a steady-state two-dimensional thermal analysis, the non-linear differential equation of semicircular fin model has been solved using finite-difference method. Two-dimensional temperature distribution of the fin surface has been successfully correlated to a third-degree polynomial. Results show that for a cooling fin with increase in tube size fin efficiency remains nearly the same or decreases for a given number of fin depending on whether fin number is large or small and whether tube size is slightly large or much larger. With increase in fin number for a given tube size, efficiency remains nearly the same or increases depending on whether fin numbers are a few more or many more and whether tube size is small or large. The efficiency range is 0.2875–0.311 for aluminium and 0.295–0.308 for copper corresponding to tube size from 0.01 m to 0.09 m and fin number ranging from 4 to 24. As expected, fin efficiency has been found to increase with enhancement in base temperature and reduction in ambient temperature. Results mentioned above are consistent for both copper and aluminium as fin material.

Black carbon emissions in gasoline exhaust and a reduction alternative with a gasoline particulate filter.

Black carbon (BC) mass and solid particle number emissions were obtained from two pairs of gasoline direct injection (GDI) vehicles and port fuel injection (PFI) vehicles over the U.S. Federal Test Procedure 75 (FTP-75) and US06 Supplemental Federal Test Procedure (US06) drive cycles on gasoline and 10% by volume blended ethanol (E10). BC solid particles were emitted mostly during cold-start from all GDI and PFI vehicles. The reduction in ambient temperature had significant impacts on BC mass and solid particle number emissions, but larger impacts were observed on the PFI vehicles than the GDI vehicles. Over the FTP-75 phase 1 (cold-start) drive cycle, the BC mass emissions from the two GDI vehicles at 0 °F (-18 °C) varied from 57 to 143 mg/mi, which was higher than the emissions at 72 °F (22 °C; 12-29 mg/mi) by a factor of 5. For the two PFI vehicles, the BC mass emissions over the FTP-75 phase 1 drive cycle at 0 °F varied from 111 to 162 mg/mi, higher by a factor of 44-72 when compared to the BC emissions of 2-4 mg/mi at 72 °F. The use of a gasoline particulate filter (GPF) reduced BC emissions from the selected GDI vehicle by 73-88% at various ambient temperatures over the FTP-75 phase 1 drive cycle. The ambient temperature had less of an impact on particle emissions for a warmed-up engine. Over the US06 drive cycle, the GPF reduced BC mass emissions from the GDI vehicle by 59-80% at various temperatures. E10 had limited impact on BC emissions from the selected GDI and PFI vehicles during hot-starts. E10 was found to reduce BC emissions from the GDI vehicle by 15% at standard temperature and by 75% at 19 °F (-7 °C).

A Sodium Manganese Oxide Cathode by Facile Reduction for Sodium Batteries

A nonstoichiometric sodium manganese oxide (Na(x)MnO(2+δ)) cathode useful for sodium batteries was synthesized by an ambient-temperature strategy that involved facile reduction of aqueous sodium permanganate in sodium iodide and subsequent heat treatment at 600 °C. Combined powder X-ray diffraction and synchrotron X-ray diffraction analyses confirmed the annealed sample to belong to a Na(x)MnO2 phase with a P2-hexagonal structure. The ICP-AES results confirmed the stoichiometry of the sample to be Na0.53MnO(2+δ) . Electron microscopy studies revealed the particle size of the electrode to be in the range of a few hundred nanometers. The Na0.53MnO(2+δ) cathode delivered an average discharge capacity of 170 mA h g(-1) with a stable plateau at 2.1 V for the initial 25 cycles versus sodium. Ex situ XANES studies confirmed the reversible intercalation of sodium into Na0.53MnO(2+δ) and suggested the accommodation of over-stoichiometric Mn(4+) ions to contribute towards the performance of the electrode.