Part Of CO2 Research Articles

Improved electrochemical and mechanical performance of WC-Co cemented carbide by replacing a part of Co with Al2O3

In this study, WC/xCo/6-xAl2O3 (x = 1, 2, 3 and 6 wt%) composites were fabricated through spark plasma sintering. The electrochemical and mechanical properties of the composites were comparatively investigated. Comparison of the hardness values indicated that by decreasing the cobalt content (from 6 to 1 wt%), the hardness of the composite increased. Also, by reducing the amount of Co from 6 wt% to 1 wt%, the corrosion potential of the samples increased while the corrosion current density decreased. FESEM images after corrosion test revealed that WO3 nano-flakes were formed on surface of the composites containing 3 wt % Co and 6 wt% Co.

Porous Multicomponent Mn-Sn-Co Oxide Microspheres as Anodes for High-Performance Lithium-Ion Batteries.

Porous multicomponent Mn–Sn–Co oxide microspheres (MnSnO3–MC400 and MnSnO3–MC500) have been fabricated using CoSn(OH)6 nanocubes as templates via controlling pyrolysis of a CoSn(OH)6/Mn0.5Co0.5CO3 precursor at different temperatures in N2. During the pyrolysis process of CoSn(OH)6/Mn0.5Co0.5CO3 from 400 to 500 °C, the part of (Co,Mn)(Co,Mn)2O4 converts into MnCo2O4 accompanied with structural transformation. The MnSnO3–MC400 and MnSnO3–MC500 microspheres as secondary nanomaterials consist of MnSnO3, MnCo2O4, and (Co,Mn)(Co,Mn)2O4. Benefiting from the advantages of multicomponent synergy and porous secondary nanomaterials, the MnSnO3–MC400 and MnSnO3–MC500 microspheres as anodes exhibit the specific capacities of 1030 and 750 mA h g–1 until 1000 cycles at 1 A g–1 without an obvious capacity decay, respectively.

(Keynote) Developing High Voltage Li-Ion Batteries Based on Lithium Cobalt Phosphate (LCP)

Olivine structured lithium cobalt phosphate, LiCoPO4 (LCP), is an attractive cathode material that has a theoretical energy density of 802 Wh/kg based on LCP’s 4.8 V redox potential and 167 mAh/g theoretical capacity. The investigation of this material was first reported in 2000 by Amine et al. [1] realizing a capacity of only 70 mAh/g. The low capacity was attributed to both the poor electronic conductivity of LCP and the initiation of the electrolyte salt decomposition [1]. Considerable efforts worldwide since then made on improving the utilization of LCP through the reduction of particle size, carbon blending, carbon coating and morphology improvement have led to an increase of capacity utilization to 140 mAh/g [2]. Efforts have also been made in developing compatible high voltage electrolytes [3]. However, these efforts had not resulted in a rechargeable LCP without substantial loss of capacity in limited cycles. A breakthrough in improving the cycle life of LCP against Li up to 500 times with 80% capacity retention was made by substituting part of Co by Fe, which was first reported by Allen et al. in 2011 [4]. Further substitutions by Cr and Si in Fe substituted LCP (s-LCP) with improved electrolyte improve the discharge capacity to 140 mAh, coulombic efficiency to 99.7% and cycle up to 250 times with almost no capacity fade [5]. The success in realizing the potential of this material is attributed to the success in modifying the electronic structure and stabilizing the electrochemical stability of LCP through atomic level substitutions. Good cycle life has also been demonstrated in full cells made of graphite anode and s-LCP cathode in coin cells and 1.2 Ah pouch cells [6]. This talk will present a progression of the s-LCP based Li-ion cells development and the importance of the atomic level engineering in improving the performance of the high voltage cathodes. References K. Amine, H. Yasuda, M. Yamachi, Olivine LiCoPO4 as 4.8 V Electrode Material for Lithium Batteries, Electrochem. Solid-State Lett. 2000, 3(4) 178-179.S.-M. Oh, S.-T. Myung, Y.-K. Sun, Olivine LiCoPO4–carbon composite showing high rechargeable capacity, J. Mater. Chem., 2012, 22, 14932.R. Sharabi, E. Markevich, K. Fridman, G. Gershinsky, G. Salitra, D. Aurbach, G. Semrau, M. A. Schmidt, N. Schall, C. Bruenig, Electrolyte solution for the improved cycling performance of LiCoPO4/C composite cathodes. Electrochem. Commun. 2013, 28, 20-23.J. L. Allen, T. R. Jow, J. Wolfenstine, Improved cycle life of Fe-substituted LiCoPO4, J. Power Sources, 2011, 196(20), 8656-8661.J. L. Allen, J. L. Allen, T. Thompson, S. A. Delp, J. Wolfenstine, T. R. Jow, Cr and Si Substituted-LiCo0.9Fe0.1PO4: Structure, Full and Half Li-ion Cell Performance, J. Power Sources, 2016, 327, 229-234.D. Liu, W. Zhu, C. Kim, M. Cho, A. Guerfi, S. A. Delp, J. L. Allen, T. R. Jow and K. Zaghib, High-Energy Lithium-Ion Battery Using Substituted LiCoPO4: From Coin Type to 1Ah Cell, J. Power Sources, 2018, 388, 52-56.

Directional Solidification of Sn-Cu6Sn5 In Situ Composites

The Sn-Cu system presents an important interest from academic and technological point of view because it is part of the family of alloys proposed as lead-free solder alloys for electronic components and also due to the mechanisms involved during the growth of the different phases. Sn-Cu system has two intermetallic phases, i.e., ε-Cu3Sn and η-Cu6Sn5, and η can be used as the negative (anode) electrode in Li-ion batteries, alone or as part of (Co,Ni)xCu6−xSn5-type composites. Obtaining this η phase from liquid with the appropriate chemical composition is a very difficult task because it has a formation temperature lower than liquidus for such a composition. In this way, the η phase appears as a consequence of a solid-solid transformation from the ε phase However, it is possible to find the η phase as the primary or secondary phase after a eutectic reaction for lower concentrations of Cu. On the other side, the Cu6Sn5 phase shows a hexagonal to monoclinic solid-solid transformation around 187°C, which could affect the mechanical system stability when it is used as solder. In this work, directional solidification at different growth velocities of hypereutectic Sn-Cu samples was performed. The resultant microstructure varies with the growth velocity, but it is formed for a fibber-like primary phase Cu6Sn5 which is projected towards the liquid phase. Behind this region, these fibbers are rounded by a two-phase Sn-Cu6Sn5 structure. In this way, three zones could to be defined in the sample during the directional growth: (i) an entirely solid two-phase region, formed by η rounded by β(Sn) + η eutectic-like structure, (ii) a two-phase solid (η) + liquid, and (iii) the remnant liquid in front of the interface.

Динаміка біопродуктивності лісів Київської області

Наведено результати моделювання компонентів фітомаси головних лісотвірних порід Київської обл. Встановлено, що від основних таксаційних ознак насаджень, які вказують у даних лісового кадастру, залежить принцип побудови моделей оцінки біопродуктивності деревостанів головних лісотвірних порід області за компонентами надземної фітомаси, який полягав у встановленні їх багатофакторних залежностей. Регресійний аналіз засвідчив, що найпридатніша з точки зору точності та практичності застосування є двофакторна модель залежності основних компонентів фітомаси насадження, в якій як фактори задіяні вік насадження та клас бонітету. Насадження Київської обл. розташовані у двох лісорослинних зонах. Під час аналізу визначено позитивну динаміку кількісних показників збільшення щільності фітомаси та вуглецю в насадженнях Київської обл., яка зросла відповідно на 8,4–4,2 кг·(м2)-1. За досліджуваний період відбулося збільшення фітомаси в 1,6 раза. Відповідно в лісорослинних зонах Полісся та Лісостепу в 1,4–2,1 раза. Лісові насадження мають великий вплив на формування навколишнього середовища і здатні впливати на такі фактори, як температура і вологість повітря на планеті. Роль лісу неможливо оцінити як щось однозначне, оскільки цей ресурс використовують у різноманітних галузях виробництва. Тому насадження Київської обл. мають важливе економічне, екологічне та соціальне значення, виконують важливі захисні та охоронні функції і є високопродуктивними.

Transformation of lignin under uniform heating. II. Combustion in a flow of water-oxygen mixture

The research results on the lignin oxidation in a flow of water-oxygen mixture at uniform heating (1.5 K/min) of the tubular reactor to 733 K are presented. The temperature dependences of the products yield and composition are obtained. It is shown that 90.3% of carbon is removed from lignin as part of CO2 and CO. The maximum yield of phenols was detected at T < 583 K. Based on time dependences of the reactor wall temperature and power of the resistive heaters, it was revealed that the most intense oxidation occurs at 583–643 K; average heat power in the oxidation of lignin is 0.5 kW. From the comparison of lignin oxidation in the Ar/O2 flow (thermogravimetric analysis) and in the H2O/O2 mixture, it follows that in the latter case, the oxidation completes at a temperature by ≈ 120 K lower. According to X-ray diffraction analysis, Na6(CO3)(SO4)2, Na2SO4, and Na2CO3 are the major mineral components of residue formed during lignin oxidation by the H2O/O2 mixture. The conversion residue includes the stainless-steel corrosion products.

The Optimization of Hybrid Air Ventilation System Combined with Silica Gel and Thermoelectric Using Monitoring Control

In this paper, the experimental is evaluated temperature, humidity and air pollution from CO&lt;sub&gt;2&lt;/sub&gt; by monitoring control of hybrid air ventilation for producing fresh air. The experimental divided into 2 conditions: hybrid air ventilation on-off, recovery silica gel unit. That research consider of a voltage of thermoelectric devices relative with air cooling under thermal comfort zone Thailand climate conditions. In the experimental was designed by the DOAS system (dedicate outdoor air system) concept. Whereas, the hybrid air ventilation was improved by old air ventilation which the hybrid air ventilation combined with silica gel unit and thermoelectric device. Monitoring control is written by Arduino program that is open source for control performance of processes such as sensors, electric current and fan unit. That working is specified temperature and humidity Thailand thermal comfort range. In the part of CO&lt;sub&gt;2&lt;/sub&gt; was released rate approximately 900 ppm corresponded with indoor air quality standard (IAQs). The results of experimental suggested that in case of hybrid air ventilation system explained thermal, humidity and CO&lt;sub&gt;2&lt;/sub&gt; distribution due to the system was adapted significantly in the comfort zone temperature and humidity about 28 and 58% respectively. However, the CO&lt;sub&gt;2&lt;/sub&gt; released into the hybrid air ventilation although control during 900 – 1,000 ppm. High CO&lt;sub&gt;2&lt;/sub&gt; concentration in comfort zone used the hybrid air ventilation that decreased CO&lt;sub&gt;2&lt;/sub&gt; inlet under ASHRAE 62.2. Therefore, the experimental is an evaluation of monitoring control hybrid air ventilation for management comfort zone. Finally this research concept of the optimization of the hybrid air ventilation combination with thermoelectric devices and silica gel unit.

A comparative study on structures and magnetic properties of SmCo4B and SmCo3.1Fe0.9B ribbons

The phase compositions, atomic structures and magnetic properties of as-spun SmCo4B and SmCo3.1Fe0.9B ribbons are comparatively studied. It was found that SmCo4B and SmCo3.1Fe0.9B ribbons consist of single SmCo4B or Sm(Co,Fe)4B phase, respectively. The SmCo4B phase displays homogeneous equiaxed grains, which contact each other directly, while Sm(Co,Fe)4B phase does not expose its clear grain profile. The Extended X-ray Absorption Fine Structure (EXAFS) analysis shows that both interatomic distance and disorder degree increase when a part of Co is substituted by Fe in SmCo4B ribbons. Such change in atomic structure increases the effect of atomic mismatch and the glass-forming ability of SmCo4B ribbons, but reduces the magnetocrystalline anisotropy. Annealing is quite helpful to improve the magnetic properties of SmCo3.1Fe0.9B ribbons.

CO CLUSTER FORMATION IN TiO2 DMS AND A METHOD OF ESTIMATION

The paper presents experimental observations of the Co cluster formation in TiO2/Co powder samples prepared by the Sol-Gel method. The obtained X-ray diffraction patterns and Raman scattering show that the anatase phase of TiO2 was successfully synthesized at an annealing temperature of 450°C. Comprehensive studies by means of X-ray diffraction, Raman scattering, thermal magnetization in a temperature range of 300–1000 K and magnetic hysteresis at room temperature confirm that a part of Co did not substitute for Ti in TiO2 structure, otherwise it has reasonably formed cluster of Co in samples. Based on the thermal magnetization curves a method to estimate the magnetic moment per one Co ion substituted for Ti in TiO2 structure was proposed. By means of this method the volume of Co substituted for Ti has been estimated for samples annealed at various temperatures around 450°C. The obtained results show that the volume of Co cluster rises when the annealing temperature increases. This obtained result persuasively explains the large divergence in the magnetic moment per one Co ion reported in the most published papers.

Effect of Al2O3 ceramic binder on mechanical and microstructure properties of spark plasma sintered WC-Co cermets

This study investigates how the partial replacement of Co with Al2O3 ceramic binder has an effect on the sintering behaviour, microstructure, and final mechanical properties of WC-Co cermets via spark plasma sintering. To examine this, three batches (WC-6wt%Co, WC-3wt%Co-3wt%Al2O3, and WC-6wt%Al2O3) were mixed through high energy ball mill, and sintering was carried out at temperatures of 1350°C and 1600°C. The results showed nearly full dense WC-Co cermets at different temperatures. It was shown that WC-6wt%Al2O3, in comparison to reference WC-6wt%Co cermet, not only led to the rise in sintering temperature from 1350°C to 1600°C, but also reduced its strength and toughness. But replacing some part of Co with alumina (WC-3wt%Co-3wt%Al2O3) exhibited the combination of high strength (1095MPa), hardness (17.62GPa), and fracture toughness (19.46MPa·m1/2).

Exploration of CoSi-based alloys promising for thermoelectricity

The cobalt silicide CoSi seems a suitable material for thermoelectricity: it is inexpensive and non-toxic, but its thermal conductivity is large. Forming CoSi-based alloys by replacing part of Co or Si with a heteroatom M can change electronic properties and improve thermoelectric performances. The insertion energy of different CoSi-based alloys containing abundant, inexpensive and non-toxic elements was estimated by using DFT calculations. Several alloys were synthesized using arc-melting or powder reaction and then characterized using X-Rays powder Diffraction (XRD) and Electron Micro Probe Analysis (EMPA) to determine the limit of solubility of these heteroatoms within CoSi. DFT predictions of solubility limit were in qualitative agreement with experimental results. Vibrational and thermoelectric properties were measured for alloys containing highly soluble elements (Mn and Cr) but also poorly soluble ones (Ti and V). These new CoSi-based alloys, studied for the first time for thermoelectric applications, do not exhibit a notable improvement of the performances.

Striking a Balance between Profit and Carbon Dioxide Emissions in the Saudi Cement Industry

Abstract Cement manufacturing is a major industry in Saudi Arabia. As a highly polluting sector, it may be part of CO 2 abatement policy for the country. This paper presents a multi-criteria analysis to examine how two competing objectives affect the performance of the cement industry in Saudi Arabia. Namely, these criteria are profit and CO 2 emissions. We examine the joint effects of economic costs and biases of the industry’s senior management on decisions. Relevant decisions include fuel use, and investment in carbon capture and storage and more energy efficient kilns. The analysis adopts an operational model that we have developed for the industry, where 2015–2020 is the period of interest. It allows us to account for events that are not anticipated by the industry, such as the rise in energy prices that took place in 2016. Allowing imports and deeming the reduction of CO 2 emissions as highly important, the industry would choose to import clinker and bypass the pyroprocessing stage in manufacturing; however, the country has broader local content and economic diversification requirements that make this infeasible. By not permitting imports to observe the actual operation of the industry at all levels, we find: ● In environmental regulations and depending on the CO 2 price, behavioral considerations have a major impact on the decision-making process of cement manufacturers. ● For a low carbon price of up to 1 $/ton, the industry would have to care for emissions considerably in order to mitigate it. At 45 $/ton or above, behavioral considerations have a limited impact in the wake of profits. ● An example of a policy that could induce a reaction is one that consists of a carbon price of 27 $/ton. At that price, the industry’s decision-makers do not have to weigh pollutants highly relative to the industry’s profits. The policy would garner $4.9 billion in government revenue and reduce emissions by 181 million tons in the six-year period. The deal would generate $1.3 billion in profit in 2020, compared to $2.5 billion without government intervention.

Intracellular position of mitochondria and chloroplasts in bundle sheath and mesophyll cells of C3 grasses in relation to photorespiratory CO2 loss

In C3 plants, photosynthetic efficiency is reduced by photorespiration. A part of CO2 fixed during photosynthesis in chloroplasts is lost from mitochondria during photorespiration by decarboxylation of glycine by glycine decarboxylase (GDC). Thus, the intracellular position of mitochondria in photosynthetic cells is critical to the rate of photorespiratory CO2 loss. We investigated the intracellular position of mitochondria in parenchyma sheath (PS) and mesophyll cells of 10 C3 grasses from 3 subfamilies (Ehrhartoideae, Panicoideae, and Pooideae) by immunostaining for GDC and light and electron microscopic observation. Immunostaining suggested that many mitochondria were located in the inner half of PS cells and on the vacuole side of chloroplasts in mesophyll cells. Organelle quantification showed that 62–75% of PS mitochondria were located in the inner half of cells, and 62–78% of PS chloroplasts were in the outer half. In mesophyll cells, 61–92% of mitochondria were positioned on the vacuole side of chloroplasts and stromules. In PS cells, such location would reduce the loss of photorespiratory CO2 by lengthening the path of CO2 diffusion and allow more efficient fixation of CO2 from intercellular spaces. In mesophyll cells, it would facilitate scavenging by chloroplasts of photorespiratory CO2 released from mitochondria. Our data suggest that the PS cells of C3 grasses have already acquired an initial structure leading to proto-Kranz and further C3–C4 intermediate anatomy. We also found that in the Pooideae, organelle positioning in PS cells on the phloem side resembles that in mesophyll cells.

Quantifying air–sea re-equilibration-implied ocean surface CO2 accumulation against recent atmospheric CO2 rise

To understand better the role of ocean surface chemical buffering capacity in mitigating the recent atmospheric CO2 rise, we investigated potentials of wintertime mixed-layer dissolved inorganic carbon (DIC) to increase after re-equilibration with decadal atmospheric CO2 rise and the corresponding anthropogenic CO2 accumulation rates, based upon carbonate system chemistry over the global ocean surface above the wintertime thermocline. This is an idealized study to quantify the isolated effect of atmospheric CO2 rise on the DIC content of the global mixed layer, assuming all else constant. Our results show that the potentials of wintertime DIC over the global open ocean surface to rise after re-equilibration with the elevated atmospheric CO2 mol fraction in a reference year 2000 ranged from 0.28 to 0.70 μmol kg−1 ppm−1 (ppm = parts of CO2 per million dry air), while the global mean wintertime sea surface DIC increase rate was close to 1.0 μmol kg−1 year−1. From 1995 to 2005, the decadal mean atmospheric CO2 rise implies an anthropogenic CO2 accumulation rate of 0.40 × 1015 g C year−1 within the global ocean surface. From the 1960s to 2000s, the air–sea re-equilibration-implied ocean surface anthropogenic CO2 accumulation rate may have increased by 46 % due to the accelerated atmospheric CO2 rise. However, the chemical buffering capacity within the ocean surface may have declined by 16 % during the same period.

Simulation and experiment for oxygen-enriched combustion engine using liquid oxygen to solidify CO2

For capturing and recycling of CO2 in the internal combustion engine, Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle. However, due to the water spray nozzle need to be installed on the cylinder, which increases the cylinder head design difficulty and makes the combustion conditions become more complicated. In this paper, a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines. The proposed new method uses liquid oxygen to solidify part of cooled CO2 from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system. The other part of CO2 is sent to inlet system and mixed with oxygen, which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable. Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program. The effects of exhaust gas recirculation (EGR) rate are analyzed on the temperatures, the pressures and the instantaneous heat release rates when the EGR rate is more than 8%. The possibility of enclosing intake and exhaust system for engine is verified. The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO2 capture experiment is carried out. The experimental results show that when the EGR rate is 36% for the optimum EGR rate. When the liquid oxygen of 35.80–437.40 g is imported into the device and last 1–20 min, respectively, 21.50–701.30 g dry ice is obtained. This research proposes a new design method which can capture CO2 for vehicular internal combustion engine.

On the role of CoO in CoOx/TiO2for the photocatalytic hydrogen production from water in the presence of glycerol

AbstractThe photocatalytic water splitting activity of nanocomposite photocatalysts of TiO2 with CoOx was studied under UV and visible light, and the catalysts were characterized by XRD, XPS, and UV–vis techniques. The presence of CoOx enhances the hydrogen production activity of TiO2 by five times at an optimal loading of .2 wt. %. To investigate the role of CoOx, the photocatalytic activity was also studied under visible light and with different amounts of sacrificial agent. Our results indicate that the increasing activity was not due to increasing absorption of the visible light but most likely due to the role of CoOx nanoparticles as hole scavengers at the interface with TiO2. XPS Co2p analyses of CoO/TiO2 showed a considerable decrease in their signal after prolonged reaction time (44 h) when compared to that of the fresh catalyst. Because part of Co2+ cations is dissolved in solution, in neutral or acidic pH, the possible increase in the reaction rate upon their addition to TiO2 under UV excitation...

Mineralization of Para-Chlorobenzoic Acid in Water by Cobalt-Incorporated MCM-41 Catalyzed Ozonation

Cobalt-incorporated MCM-41(Co-MCM-41) was used as a heterogeneous catalyst for the ozonation of para-chlorobenzoic acid (p-CBA) in aqueous solution. Cobalt oxide supported on MCM-41(Co/MCM-41) was synthesized for comparison. Their textural properties were elucidated by various characterization techniques to understand the relationship between surface texture and catalytic activity. TOC removal at 60 min reached 91% with Co-MCM-41, 83% with Co/MCM-41 and only 52% with ozone alone, respectively. Observations from diffuse reflection spectroscopy demonstrated that different metal phases were formed in these cobalt-modified molecular sieves samples. Radical scavenger experiments indicated the formation of hydroxyl radicals that were responsible for the effective degradation of p-CBA. An integrated approach to the catalytic mechanism was proposed by considering the variation of pH in the course of ozonation as well as its subsequent influence on the dissociation of targeted compounds and surface charge of the catalyst. In the reusability experiments, the reused Co-MCM-41 was able to regain the same catalytic capability as the fresh one within 5 cycles. X-ray photoelectron spectroscopy results indicated that a part of Co2+ was oxidized to Co3+ after oxidation reaction.

Menstrual characteristics and ultrasonographic uterine cavity measurements predict bleeding and pain in nulligravid women using intrauterine contraception.

Is small uterine cavity size as assessed by ultrasonography associated with bleeding problems or pain in nulligravid women using intrauterine contraception, or do other factors affect these parameters? Among levonorgestrel intrauterine system (LNG-IUS) users, small uterine cavity size is not associated with worsened clinical outcome, but is beneficial as women with the smallest cavity measurements were frequently amenorrhoeic and painless at the end of the first year but among copper intrauterine device (IUD) users, no associations between uterine cavity dimensions and clinical outcome were found. Nulligravid and nulliparous women have smaller uterine dimensions than parous women. Previously, many studies have revealed increased discontinuation rates of IUD use as a result of bleeding, pain or expulsion in these women, while recent studies with current models of IUS/IUDs indicate similar continuation and satisfaction rates irrespective of parity. In a pilot study, 165 adult nulligravid women requesting their first IUD between 1 January 2011 and 31 July 2012 were given a free choice between two IUDs with equal frames measuring 32 × 32 mm-the LNG-IUS 52 mg or a copper-releasing IUD. The women were followed for 1 year. The LNG-IUS was chosen by 113 women (68.5%) and the copper IUD by 52 (31.5%). Prior to insertion the women were interviewed concerning their menstrual characteristics and uterine cavity size was measured by 2-D ultrasonography. After insertion the women kept daily records of bleeding and pain for two reference periods of 90 days during the first year (Months 1-3 and 10-12). The correlation between uterine cavity measurements and numbers of days of bleeding/spotting and pain during the reference periods was analysed. Continuation rates were assessed and reasons for discontinuation as well as the effects of baseline participant characteristics on outcomes were analysed in regression models. Both uterine cavity size and baseline menstrual characteristics prior to IUD insertion predicted the numbers of days of bleeding/spotting and pain in LNG-IUS users. Women with small uterine cavity dimensions reported less bleeding/spotting in both reference periods and less pain in the second reference period compared with women with larger dimensions. Baseline scanty spontaneous menstrual bleeding prior to LNG-IUS use (OR 9.4, 95% CI 1.7-51.8, P = 0.01) and smoking (OR 7.8, 95% CI 1.8-33.8, P = 0.006) predicted amenorrhoea in the second reference period. Women with baseline dysmenorrhoea reported more pain with both IUDs. Continuation rates and reasons for discontinuation were similar with both IUDs. No sample size could be calculated to estimate the power as this was a pilot study. As the majority of women chose the LNG-IUS we did not achieve our initial aim of equally sized IUD groups and thus the size of the copper IUD group may have been insufficient to detect differences. These data further encourage promotion of intrauterine contraception among nulligravid women. Routine use of ultrasonography to assess uterine cavity dimensions prior to IUD insertion is not indicated. Supported by Helsinki University Central Hospital research funds, the Swedish Cultural Foundation in Finland and Finska Läkaresällskapet, who provided funds for J.K. O.H. serves on advisory boards for Bayer Healthcare, Gedeon Richter and MSD Finland (part of Merck & Co. Inc.) and has designed educational events with these companies. S.S. has lectured in educational events at Bayer and MSD Finland (part of Merck & Co. Inc.) and is a member of the Advisory Board for Contraception at MSD Finland. The other authors have no conflicts of interest to declare. www.clinicaltrials.gov, NCT01685164.

Development of a road transport emission inventory for Greece and the Greater Athens Area: Effects of important parameters

Traffic is considered one of the major polluting sectors and as a consequence a significant cause for the measured exceedances of ambient air quality limit values mainly in urban areas. The Greater Athens Area (located in Attica), the most populated area in Greece, faces severe air pollution problems due to the combination of high road traffic emissions, complex topography and local meteorological conditions. Even though several efforts were made to construct traffic emission inventories for Greece and Attica, still there is not a spatially and temporally resolved one, based on data from relevant authorities and organisations. The present work aims to estimate road emissions in Greece and Attica based on the top down approach. The programme COPERT 4 was used to calculate the annual total emissions from the road transport sector for the period 2006–2010 and an emission inventory for Greece and Attica was developed with high spatial (6×6km2 for Greece and 2×2km2 for Attica) and temporal (1-hour) resolutions. The results revealed that about 40% of national CO2, CO, VOC and NMVOC values and 30% of NOx and particles are emitted in Attica. The fuel consumption and the subsequent reduction of annual mileage driven in combination with the import of new engine anti-pollution technologies affected CO2, CO, VOC and NMVOC emissions. The major part of CO (56.53%) and CO2 (66.15%) emissions was due to passenger cars (2010), while heavy duty vehicles (HDVs) were connected with NOx, PM2.5 and PM10 emissions with 51.27%, 43.97% and 38.13% respectively (2010). The fleet composition, the penetration of diesel fuelled cars, the increase of urban average speed and the fleet renewal are among the most effective parameters towards the emission reduction strategies.

Preparation of Co/Al2O3 catalyst for Fischer–Tropsch synthesis: Combination of impregnation method and homogeneous precipitation method

Co(20wt.%)/γ-Al2O3 catalysts were prepared by four methods, i.e., impregnation method (Imp), two kinds of precipitation methods using aqueous solution of ammonia (Pa) or ammonium oxalate (Pao) as the precipitant and homogenous precipitation method (HP). The prepared Co/Al2O3 catalysts were characterized by XRD, H2-TPR, H2 chemisorption and TEM-EDS, and the catalytic activity for Fischer–Tropsch (FT) synthesis was evaluated with the continuously stirred tank reactor. For the Co/Al2O3 catalysts prepared by the Imp and Pa methods, the reducibility of Co and the surface area of Co metal were low, but the intrinsic activity per active Co metal species (TOF) was high. On the other hand, for the Co/Al2O3 catalysts prepared by the Pao and HP methods, the reducibility of Co and the surface area of Co metal were high, but the TOF was low. Thus, the overall reaction rate increased in the following order: Pao<HP<Pa<Imp. Combination of the Imp and HP methods was also examined for the preparation of Co/Al2O3 catalysts; that is to say, part of Co was loaded by the HP method, followed by loading with the rest of Co by the Imp method. Co/Al2O3 catalysts prepared by this two-step procedure (Co(x, Imp)/Co(y, HP)/Al2O3, x+y=20) showed higher activity than those prepared by either the Imp method (Co(20, Imp)/Al2O3) or the HP method (Co(20, HP)/Al2O3), and the Co(15, Imp)/Co(5, HP)/Al2O3 catalyst showed the best performance. The high activity of the Co(x, Imp)/Co(y, HP)/Al2O3 catalyst is originated from the coexistence of two different kinds of Co species, i.e., easily reducible Co species derived from the HP method and highly active Co species derived from the Imp method. These two kinds of Co species cooperatively promoted the reduction and the dispersion of Co metal to enhance the overall catalytic activity.