bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Investigation on the Use of Secondary Refrigerant in Freezer for Energy Savings
Authors: Haryono Aries Prih , Sukamto Edi , Sumeru K. , Ani Farid Nasir
Published: January 2014

This study presents an experimental study on a freezer which has small cooling capacity. Typically a freezer uses primary refrigerant (direct cooling) to cool or freeze a product. In this study, a prototype of freezer using a compressor 250 W nominal power at 220V was designed and constructed. The freezer is operated on two conditions, that is, using primary and secondary refrigerant. R22 and R290 (propane) were used as primary refrigerant, whereas aqueous solution of propylene glycol as secondary refrigerant. Comparison of the system performance between the primary and the secondary refrigerant werepresented. Also, the experimental results showed that the use of R290 as primary refrigerant to replace R22 in the freezer could save electrical power consumption by 18.5%. Meanwhile, the use of the secondary refrigerant yielded energy savings by 33.19% compared with the primary refrigerant.
Investigation of Natural Gas Composition Effects on Knock Phenomenon in SI Gas Engines Using Detailed Chemistry
Authors: Javaheri Ahmad , Esfahanian Vahid , Salavati-Zadeh Ali , Darzi Mehdi , Mirsoheil Seyyed Mojtaba
Published: January 2014

Considering the growing role of natural gas as an alternative fuel in stationary and automobile engines and the differences in its composition, the influence of natural gas composition on knocking combustion in spark ignition gas engines is studied both experimentally and by employing detailed chemistry. A SI single cylinder gas engine with variable compression ratio has been used for experimental observations. The chemical scheme is embedded into a zero-dimensional model which employ three-zone approach. The scheme is used to simulate the post-flame heat release and pre-flame auto-ignition. The reactions in burning zone are modeled by chemical equilibrium calculations. The simulated results are in good agreement with the experimental observations.
Experimental Study on the Performance of In-Cabin Ventilation System
Authors: Zulkarnain Abdul Latiff , Soon Cheong Weng , Supriyo Bambang , Mohd Perang Mohd Rozi , Nasution Henry , Aziz Azhar Abdul
Published: January 2014

Parking a car under the hot sun with all windows closed could increase in-cabin temperature as high as 70°C. For such situation, human occupancy will exposed to thermal shock and inconvenience when embarking the vehicle. Another concerned of this accumulated heat gain is the effect of gas emitted by the interior material which mostly is made of vinyl. These experimental studies try to look the possibilities of bringing down the temperature and hence to suit human habitation. In this study, two methods were implemented and they are by creating fresh air change and introducing evaporative cooling by generating water mist in the air flow for further enhancement of temperature drop. Fully automated control strategy was used based on in-cabin temperature activation by the assistance of electronic control unit (ECU). Observation was made and compare for original car condition and the one equipped with In-Cabin Ventilation (IVS). The result shows the car cabin temperature can reach as high as 65°C without ventilation. With fresh charged of air and evaporative cooling, temperature drops to a range of 40 to 50°C.
The Evaluation of a Rigid Sail of Ship Using Wind Tunnel Test
Authors: Sulisetyono Aries
Published: January 2014

This paper described the evaluation of rigid sail performances by using the wind tunnel test. The rigid sail models were developed in the three variations of shape geometry which was having the same value of aspect ratio. The tests were performed to investigate the performances of sail models in terms of lift, drag, resultant, driving and heeling coefficient. The three sail models were tested at the variation of angle of attack such as 15o, 20o and 25o respectively, and it was fluided by a uniform flow of air with three different speeds. The comparisons of test results were evaluated to look for which sail models had the best performance. Based on the test results, Model 2 which is a triangle shape had generated a maximal efficiency and thrust force compare to the other models.Keywords: rigid sail, wind tunnel, sailing ship, renewable energy
Design of a Bubbling Fluidized Bed Gasifier for the Thermochemical Conversion of Oil Palm Empty Fruit Bunch Briquette
Authors: Johari Anwar , Nyakuma B.B. , Ahmad A. , Abdullah T.A. Tuan , Kamaruddin M.J. , Mat R. , Ali A.
Published: January 2014

This paper is focused on the design of a bubbling fluidized bed gasifier (BFBG) for EFB briquette gasification. The annual production of palm oil in Malaysia generates large quantities of lignocellulosic biomass which can be converted into clean, sustainable energy for the future. Hence, the prospect of valorising palm waste using biomass gasifiers presents a viable option for energy production. The fluidized bed gasifier (FBG) is considered the most suitable reactor for biomass gasification due excellent mixing, efficient heat temperature control and tolerance for fuels. Consequently, the proposed design of the bubbling fluidized bed gasifier for EFB briquette gasification will consist of three main parts; feeding zone, gasification zone and the effluent gas zone for syngas production. The results of feedstock physicochemical properties such as bulk density, particle size, the bed hydrodynamic and fluidization parameters for gasification used in the design of the gasifier are presented in this paper.
Kerosene-Water Flow Pattern in T-Junction Vertical Diameter Ratio 0.5 (Variation of Inclination Branch)
Authors: Puspitasari Dewi , Indarto Indarto , Purnomo Purnomo , Khasani Khasani
Published: January 2014

The separation is one of the important processes in exploration and production oil technology. Phase separation across T-junction with orientation vertical up branch is simplicity method to achieve maximum efficiency, but useful information is rather limited. This paper is presented only for inlet flow pattern and T-junction flow pattern of kerosene water mixture with inlet diameter 36 mm and branch diameter 19 mm (diameter ratio 0.5) on the variation inclination branch are 30o, 60o and 90o. Regulating flow by closing valve at downstream was done to obtain three flow resistance in the downstream. The flow pattern obtained in this study were : stratified (ST), three-layer-13 (3L-13) , three layer-2 (3L-2), and three layer-3 (3L-3). The results of the phase separation is best achieved under conditions inlet flow pattern stratified (ST) and T-junction three layer-3 (3L-3) flow pattern, angle 90 ° and downstream resistance 6471 Pa.Keywords: phase separation, T-junction, flow patterns, downstream resistance.
The Influence of Hydrogen Addition to Diesel Fuel Spray Combustion for Different Atomization Conditions
Authors: Sriwardani Nyenyep , Okamoto Yuya , Seo Takehiko , Mikami Masato
Published: January 2014

The negative effects of hydrocarbon fuels are widely highlighted by increasing global warming and declining quality of human health. Therefore, it is important to reduce the level of emissions from liquid hydrocarbon combustion. Hydrogen addition to the combustion chamber is one of the proven methods to improve emssions level. In this research, an experiment was conducted on diesel fuel spray combustion with hydrogen addition. The effect of additional hydrogen was observed on CO, CO2, NO and THC exhaust gas emissions. A small hydrogen fraction (0~3 vol %) was added to the rich premixed spray combustion. The results show that increasing the hydrogen fraction reduced the emission indexes of CO and THC, and increased the emission index of CO2. Increasing the hydrogen fraction caused an increase in the emission index of NO, but the actual physical amount was insignificant. Increasing the atomizing air flow rate reduced the CO and THC emission indexes, but increased the CO2 and NO emission indexes.
Computer Assisted Fracture Reduction and Fixation Simulation for Pelvic Fractures
Authors: Lee Pei Yuan , Lai Jiing Yih , Huang Chung Yi , Hu Yu Sheng
Published: January 2014

Abstract. The objective of this study is to present an integrated surgical simulation program on a personal computer for the preoperative planning of pelvic fractures. It first provides a visualization module to display 2D images and 3D model simultaneously. A semi-automatic bone segmentation module is then provided to separate the bony structures, enabling the manipulation of individual fractured bone and bone fragment. A bone reduction module is provided for the localization of the fractured bones. The simulation of plate and screw fixation is also presented, which provides useful information for determining the shape and size of the implants. Also, an example with real CT images are presented to demonstrate the feasibility of the proposed method.
Split Bar Hopkinson with Springs Striker Bar Launcher
Authors: Pramono Agus Sigit , Sujarwanto Sujarwanto , Rivazani Handik
Published: January 2014

Research on the dynamic strength of various materials such as metallic materials, polymers, concrete has been done by many researchers. The Split Hopkinson Bar method is still used to produce a high strain rate. In this method, a striker bar is usually launched using pressurized gas. However, high security system is required to prevent leakage as the operating pressure is very high. Avoiding the use of high-pressure gas, in this study, a mechanical system of springs used to propel the Striker Bar. By varying the spring deflection of 1 cm to 8 cm, a linear Striker Bar velocity from 2.17 m/s until 19.45 m/s is obtained. Aluminum alloy Al-2024 has been tested with this tool and it is found that at the maximum Striker Bar velocity, strain rate on the material can be reach 1132 s-1, and dynamic compression yield strength increase 56% from quasi-static compression yield strength.
Driving Efficiency through Hydrocarbon for Green Car Air Conditioning
Authors: Dahlan Afiq Aiman , Nasution Henry , Aziz Azhar Abdul , Latiff Zulkarnain Abdul , Perang Mohd Rozi Mohd , Wan Mohd A.Y.
Published: January 2014

The feasibility of hydrocarbon mixtures to replace HFC-R134a in automotive air conditioning systems is investigated in this paper. The temperature distribution in car cabin and fuel consumption are evaluated at various passenger load and vehicle speeds using hydrofluorocarbons refrigerant (HFC-R134a) and hydrocarbon refrigerant as the working fluid of the compressor. The experiments are tested in an actual petrol engine vehicle on a roller dynamometer to simulate actual vehicle on level road. The experiments are conducted at the same surrounding conditions. The test has performed by varying the vehicle speed; 50, 70, 90 and 110 kph, and number of passengers; 1 and 2, at temperature set-point of 21°C. The result shows that the hydrocarbon mixtures provide excellent temperature distribution and fuel conservation effect is about 2.95% to 11.90%. In addition, the results support the possibility of using hydrocarbon mixtures as an alternative to HFC-R134a in the automotive air conditioning system, without the necessity of changing parts in the current system.
Simulation of Semi-Active the Blank Holder Force Control to Prevent Wrinkling and Cracking in Deep Drawing Process
Authors: Candra Susila , Batan I Made Londen , Berata Wajan , Pramono Agus Sigit
Published: January 2014

This paper presents simulation of drawing force and thickness deformation in deep drawing which employs semi-active blank holder force system, to solve the problem of cracking and wrinkling. The method of slab with feed back control failure criteria, was employed to make the modeling system and the semi-active blank holder to prevent wrinkling and cracking in forming low carbon steel sheet, without lubrication (μ=0.4). In this study, the mechanical properties of the material were chosen since that they equivalent to those of low carbon steel with its thickness of 0.2 mm, k = 572 N/mm2, UTS = 391 N/mm2, yield stress = 309 N/mm2 and n = 0.2. The diameter and the depth of the cylindrical cup-shaped product were 40 mm and 10 mm, respectively. Results from simulation have shown that the semi-active blank holder system can control very responsive against changing of deformation condition. The optimum of initial blank holder force is approximately 3000 N up to 4000 N. In the early stages (initial stroke), blank holder force system could be responsive to prevent cracking, and at the end of the punch stroke, it is very effective to prevent wrinkling. Simulation of semi-active blank holder force control system is excellent in model formation to prevent cracking and wrinkling.
Preliminary Study on Magnetic Levitation Modeling Using PID Control
Authors: Patriawan Desmas A. , Pramujati Bambang , Nurhadi Hendro
Published: January 2014

This paper proposes to understand about basic magnetic levitation model. Magnetic Levitation is repulsive or attractive force resulting gap from magnetic field. Characteristic of the magnetic levitation model is used permanent magnet and electromagnet with PID control to maintain wide gap between levitator and object levitation. Mass addition is used to analysis the model of the Maglev with PID control to maintain wide gap. Calculation result show that the maglev with PID control has sufficient levitation force in the maintain wide gap. Comparison between calculated and measured values can be done to build a another complex model magnetic levitation.
Multiple Performance Optimization in the Wire EDM Process of SKD61 Tool Steel Using Taguchi Grey Relational Analysis and Fuzzy Logic
Authors: Lusi Nuraini , Soepangkat Bobby Oedy Pramoedyo , Pramujati Bambang , Agustin Helena C. Kis
Published: January 2014

This paper propose the optimization of the wire electrical discharge machining (WEDM) process of SKD61 tool steel (AISI H13). The use of the Taguchi method combined with grey relational analysis and fuzzy logic has been applied for optimization of multiple quality characteristics. The WEDM machining parameters (arc on time, on time, open voltage, off time and servo voltage) were optimized with considerations of multiple performance characteristics, i.e., MRR, SR and kerf. Arc on time was set at two different levels while the other four were set at three different levels. Based on Taguchi method, an L18 mixed-orthogonal array was chosen for the experiments. Experimental results have shown that machining performance characteristics of WEDM process can be improved effectively through the combination of Taguchi method and grey-fuzzy logic.
Kamojang Geothermal Power Plant Unit-1 : 30 Years of Operation
Authors: Adiprana Reza , Purnomo Danu Sito , Setiono Iwan
Published: January 2014

UNIT-1 KAMOJANG geothermal power plant marked the new era of renewable energy in Indonesia. With its built capacity of 30 MWe, it constantly supply electricity to Java-Bali grid for more than 30 years now.Over those period, Unit-1 has given its best performance with highest achievement on Capacity Factor (CF) and Equivalent Availability Factor (EAF).High performance geothermal power plant involves the integration not only from the point of view of power generation, but also the optimation of geothermal potention in the area. Kamojang geothermal field, which is considered as one among five steam dominated reservoir in the world produces 200 MWe of the electricity nowadays. In order to maintain this production rate, some technical consideration must be made.Towards sustainable power generation of geothermal power, some assessment has been made to turbine, generator and cooling tower to ensure its current condition. Basically what it called remaining life assessment gives a rough picture of how long the equipment will run through in its operational condition.Based on those assessment, additional 20.900 hours is given to the turbine with the existing operating conditions. On the other hand, cooling tower infrastucture test and simulation delivers operation period for another 25 years.
Microstructure Study on Fe/Cr Based Alloys Added with Yttrium Oxide (Y2O3) Prepared via Ultrasonic Technique for Solid Oxide Fuel Cell (SOFC) Application
Authors: Feriyanto Dafit , Idris Maizlinda Izwana , Sebayang Darwin , Bin Otman Ashraf , Untoro Pudji
Published: January 2014

Solid oxide fuel cells (SOFC) are the current research having several potential to obtain high efficiency, high energy–density power generation which operated at relatively higher temperature. Yttrium oxide (Y2O3)contributions at high temperature are accelerating to the development oxide layer of FeCr alloy. The aim of this research is to investigate the microstructure of Fe/Cr added with Y2O3 acting as a reactive element. The purpose is to improve macrostructure of Fe/Cr powders which can be applied at steel industry. In this study the mixing process of Fe/Cr and Y2O3 powder was conducted via ultrasonic treatment at a frequency of 22 kHz, and at two different holding time of 2.5 h and 3.5 h. The particle size of chromium (Cr) can be reduced by ultrasonic treatment at from 60µm to 30µm through threshing the cluster of Cr particle. It shows that the ultrasonic vibration effectively removes oxides and other contaminates on a surface coating. Therefore, homogeneity of the parent material, segregation, and uniform distribution of second phase were increased.
Na2SO4 Induced Hot Corrosion of Aluminized Low Carbon Steel at 700 °C
Authors: Badaruddin Mohammad
Published: January 2014

The oxidation kinetics of hot-dip aluminized AISI 1020 steel with Na2SO4 deposit was investigated at 700 °C for 49 h in static air. The scale morphologies were observed by means of metallograpy, scanning electron miscroscopy (SEM), electron dispersive spectroscopy (EDS) and X-ray analyses. The accelerated oxidation of aluminized steel was attributed to the formation of aluminum-sulphides which allowed the rapid diffusion of Fe ions in the aluminide layer to the formation of iron oxide. In addition, the Al-sulphides precipitations in the alumina scale causes the Al-depletion such that Al2O3 layer fails to form a protective layer. Consequently, the kinetics rate of aluminized was increased.
Experimental Studies on a Solar Air Heater Having V-Corrugated Absorber Plate with Obstacles Bent Vertically
Authors: Handoyo Ekadewi A. , Ichsani Djatmiko , Prabowo Prabowo , Sutardi Sutardi
Published: January 2014

A solar air heater (SAH) is a simple heater using solar radiation that is useful for drying or space heating. Unfortunately, heat transfer from the absorber plate to the air inside the solar air heater is low. Some researchers reported that obstacles are able to improve the heat transfer in a flat plate solar air collector and others found that a v-corrugated absorber plate gives better heat transfer than a flat plate. Yet, no work of combining these two findings is found.This paper describes the result of experimental study on a SAH with v-corrugated absorber plate and obstacles bent vertically started from 80o to 0o with interval 10o on its bottom plate. Experiments were conducted indoor at five different Reynolds numbers (1447 Re 7237) and three different radiation intensities (430, 573, and 716 W/m2).It is found that the obstacles improve SAH performance. Both the air temperature rise and efficiency increase with inserting obstacles bent at any angle vertically. Unfortunately, the air pressure drop is increasing, too. Obstacles bent vertically at smaller angle (means more straight) give higher air temperature rise and efficiency. However, the optimum angle is found 30o. The air temperature rise and efficiency will be 5.3% lower when the obstacles bent 30o instead of 0o, but the pressure drop will be 17.2% lower.
Energy Savings in Air Conditioning System Using Ejector: An Overview
Authors: Sumeru K. , Martin Luga , Ani Farid Nasir , Nasution Henry , Ani Farid Nasir
Published: January 2014

There are two ejector configurations described in the present study: ejector refrigeration cycle and the ejector as an expansion device. The use of waste heat from the car engine and industry as a heat-driven energy for air conditioning system in automobile and building can save energy. Although the ejector refrigeration cycle has a low COP, the use of waste heat as a heat-driven energy incurs a lower operational cost compared with vapor compression refrigeration system. In addition, an ejector as an expansion device can be applied in the vapor compression refrigeration cycle to improve the performance system.
Quanitative Analysis of the Polymer/Metal Powder Magentic Composites Compacts Structure
Authors: Paszkowski Lech , Biało Dionizy , Bucki Janusz , Skalski Andrzej
Published: January 2014

The work pertains to research of inhomogeneity level of the composite compacts manufactured from flaky metal particles and polymer binder. In the present investigation, magnetically hard Nd-Fe-B powders were used. The composite matrix was in all cases polystyrene. Volume fraction of the powders in composites was 40 ÷ 54%. As the forming method injection moulding was used. Granulates were obtained from powders and polystyrene dissolved with toluene. Produced cylindrical specimens had 10 mm in diameter and 4 mm in height. The structure of specimens was determined on the basis on quantitative analysis of the micrographs of axial sections. The analysis of binary images of metallographic specimens allowed to determine homogeneity and directions of flake distribution. Standard deviation of surface fraction is a measure of inhomogeneity which shows relatively well both local and general differences in the distribution of particles. The greater the volume of powder Vp in composites, the lower standard deviation S. The size of particles also influences the value of standard deviation. The greater the size of particles in a composite, the greater the values of S. In the next research, information about inhomogeneity will be useful in estimation of distribution of mechanical and magnetic parameters of the compacts (dielectromagnets) formed in this way.
Research of the Elastic Properties of Bellows Made in SLS Technology
Authors: Kundera Czeslaw , Kozior Tomasz
Published: January 2014

The article contains the result of studies on the effects of selected geometrical parameters of elastic bellows on their elastic properties. Bellows models were produced with using additive technology, selective laser sintering SLS, where the material used to build models was polyamide PA 2200. Based on the measurements of elastic deformation coefficients of each models bellows were determined. Comparing the results of the measurements there was found a significant effect of the thickness, number of corrugations and their length on the value of the coefficient of elasticity.
Experimental Analysis of Fatigue Life of Laser Weld Zones
Authors: Boroński Dariusz
Published: January 2014

This paper presents possibilities of determination of a material fatigue life for particular laser weld zones using specimens of micrometer dimensions. An original research system MFS developed at the University of Technology and Life Sciences in Bydgoszcz has been used whose research possibilities have been illustrated on the example of fatigue life tests of welds made of steel S 355J2G3.
Influence of Pearlite Morphology on Creeping Characteristic Curves of R260 Steel
Authors: Cieśla Marek , Herian Jerzy , Junak Grzegorz
Published: January 2014

The elements of railway turnouts made from rail sections of R260 high carbon steel must have a high resistance to abrasive and contact fatigue wear, as well as a good resistance to cracking under service loads. These mechanical properties largely determine the suitability of steel for use as railway track components. In this study, two groups of specimens were subjected to tests of mechanical properties and metallurgical analyses. The first group included material obtained from the hot-rolled block section, the rolling end temperature being Tkw = 950°C, while the second group was material after the rolling process with the subsequent 20-minute isothermal annealing at a temperature of 480°C. The microstructure of tested materials (Rm, Rp0.2, A5, Z, HB) was characterized, and their basic mechanical properties and fracture toughness in the KIc plane strain condition were determined. Also the effect of temperature, ranging from-80°C to 100°C, on the KCU impact toughness of R260 steel was established. Based on the SEM observation using the Hitachi S-3400N scanning microscope, it was found that pearlitic structure with a varied distance between cementite plates, equal to 0.29 μm and 0.09 μm, respectively, appears in the hot-rolled R260 steel and in the steel subjected to additional isothermal annealing treatment. The impact of pearlite morphology on the cracking characteristics and basic mechanical properties of materials was analyzed. It was found that at room temperature, the higher fracture toughness (KIc = 66.4 MPa·m1/2) is shown by the steel after isothermal annealing at 480°C, in which less distance between the plates of cementite has been observed in the perlite. The fracture toughness of R260 steel after hot rolling at 950°C was KIc = 48.3 MPa·m1/2. As in the case of fracture toughness, the impact strength of R260 steel after isothermal annealing was significantly greater than the impact strength of steel only after hot rolling. The determined cracking characteristics of R260 steel make it possible to determine the effect of heat treatment on the formation of microstructure and material properties, which determine the service life of rail sections.
Antarctic ozone variability inside the polar vortex estimated from balloon measurements
Authors: Parrondo M. C. , Gil M. , Yela M. , Johnson B. J. , Ochoa H. A.
Published: January 2014

Abstract. Thirteen years of ozone soundings at the Antarctic Belgrano II station (78° S, 34.6° W) have been analysed to establish a climatology of stratospheric ozone and temperature over the area. The station is inside the polar vortex during the period of development of chemical ozone depletion. Weekly periodic profiles provide a suitable database for seasonal characterization of the evolution of stratospheric ozone, especially valuable during wintertime, when satellites and ground-based instruments based on solar radiation are not available. The work is focused on ozone loss rate variability (August–October) and its recovery (November–December) at different layers identified according to the severity of ozone loss. The time window selected for the calculations covers the phase of a quasi-linear ozone reduction, around day 220 (mid-August) to day 273 (end of September). Decrease of the total ozone column over Belgrano during spring is highly dependent on the meteorological conditions. Largest depletions (up to 59%) are reached in coldest years, while warm winters exhibit significantly lower ozone loss (20%). It has been found that about 11% of the total O3 loss, in the layer where maximum depletion occurs, takes place before sunlight has arrived, as a result of transport to Belgrano of air from a somewhat lower latitude, near the edge of the polar vortex, providing evidence of mixing inside the vortex. Spatial homogeneity of the vortex has been examined by comparing Belgrano results with those previously obtained for South Pole station (SPS) for the same altitude range and for 9 yr of overlapping data. Results show more than 25% higher ozone loss rate at SPS than at Belgrano. The behaviour can be explained taking into account (i) the transport to both stations of air from a somewhat lower latitude, near the edge of the polar vortex, where sunlight reappears sooner, resulting in earlier depletion of ozone, and (ii) the accumulated hours of sunlight, which become much greater at the South Pole after the spring equinox. According to the variability of the ozone hole recovery, a clear connection between the timing of the breakup of the vortex and the monthly ozone content was found. Minimum ozone concentration of 57 DU in the 12–24 km layer remained in November, when the vortex is more persistent, while in years when the final stratospheric warming took place "very early", mean integrated ozone rose by up to 160–180 DU.
Global stratospheric fluorine inventory for 2004–2009 from Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) measurements and SLIMCAT model simulations
Authors: Brown A. T. , Chipperfield M. P. , Richards N. A. D. , Boone C. , Bernath P. F.
Published: January 2014

Abstract. Fluorine-containing species can be extremely effective atmospheric greenhouse gases. We present fluorine budgets using organic and inorganic species retrieved by the ACE-FTS satellite instrument supplemented with output from the SLIMCAT 3-D chemical transport model. The budgets are calculated between 2004 and 2009 for a number of latitude bands: 70–30° N, 30–00° N, 00° N–30° S, and 30–70° S. At lower altitudes total fluorine profiles are dominated by the contribution from CFC-12, up to an altitude of 20 km in the extra-tropics and 29 km in the tropics; above these altitudes the profiles are dominated by hydrogen fluoride (HF). Our data show that total fluorine profiles at all locations have a negative slope with altitude, providing evidence that overall fluorine emissions (measured by their F content) have been increasing with time. Total stratospheric fluorine is increasing at a similar rate in the tropics: 32.5 ± 4.9 ppt yr−1 (1.31 ± 0.20% per year) in the Northern Hemisphere (NH) and 29.8 ± 5.3 ppt yr−1 (1.21 ± 0.22% per year) in the Southern Hemisphere (SH). Extra-tropical total stratospheric fluorine is also increasing at a similar rate in both the NH and SH: 28.3 ± 2.7 ppt per year (1.12 ± 0.11% per year) in the NH and 24.3 ± 3.1 ppt per year (0.96 ± 0.12% per year) in the SH. The calculation of radiative efficiency-weighted total fluorine allows the changes in radiative forcing between 2004 and 2009 to be calculated. These results show an increase in radiative forcing of between 0.23 ± 0.11% per year and 0.45 ± 0.11% per year, due to the increase in fluorine-containing species during this time. The decreasing trends in the mixing ratios of halons and chlorofluorocarbons (CFCs), due to their prohibition under the Montreal Protocol, have suppressed an increase in total fluorine caused by increasing mixing ratios of hydrofluorocarbons (HFCs). This has reduced the impact of fluorine-containing species on global warming.
Not all calcite ballast is created equal: differing effects of foraminiferan and coccolith calcite on the formation and sinking of aggregates
Authors: Schmidt K. , De La Rocha C. L. , Gallinari M. , Cortese G.
Published: January 2014

Abstract. Correlation between particulate organic carbon (POC) and calcium carbonate sinking through the deep ocean has led to the idea that ballast provided by calcium carbonate is important for the export of POC from the surface ocean. While this idea is certainly to some extent true, it is worth considering in more nuance, for example, examining the different effects on the aggregation and sinking of POC of small, non-sinking calcite particles like coccoliths and large, rapidly sinking calcite like planktonic foraminiferan tests. We have done that here in a simple experiment carried out in roller tanks that allow particles to sink continuously without being impeded by container walls. Coccoliths were efficiently incorporated into aggregates that formed during the experiment, increasing their sinking speed compared to similarly sized aggregates lacking added calcite ballast. The foraminiferan tests, which sank as fast as 700 m d−1, became associated with only very minor amounts of POC. In addition, when they collided with other, larger, foram-less aggregates, they fragmented them into two smaller, more slowly sinking aggregates. While these effects were certainly exaggerated within the confines of the rolling tanks, they clearly demonstrate that calcium carbonate ballast is not just calcium carbonate ballast – different forms of calcium carbonate ballast have notably different effects on POC aggregation, sinking, and export.
Distinct bacterial-production–DOC–primary-production relationships and implications for biogenic C cycling in the South China Sea shelf
Authors: Lai C.-C. , Fu Y.-W. , Liu H.-B. , Kuo H.-Y. , Wang K.-W. , Lin C.-H. , Tai J.-H. , Wong G. T. F. , Lee K.-Y. , Chen T.-Y. , Yamamoto Y. , Chow M.-F. , Kobayashi Y. , Ko C.-Y. , Shiah F.-K.
Published: January 2014

Abstract. Based on two summer spatio-temporal data sets obtained from the northern South China Sea shelf and basin, this study reveals contrasting relationships among bacterial production (BP), dissolved organic (DOC) and primary production (PP) in the transition zone from the neritic to the oceanic regions. Inside the mid-shelf (bottom depth <100 m), where inorganic nutrient supplies from river discharge and internal waves were potentially abundant, BP, DOC and PP were positively intercorrelated, whereas these three measurements became uncorrelated in the oligotrophic outer shelf and slope. We suggest that the availability of limiting minerals could affect the couplings/decouplings between the source (i.e. phytoplankton) and sink (i.e. bacteria) of organic carbon, and thus DOC dynamics. DOC turnover times were homogeneously low (37–60 days) inside the mid-shelf area and then increased significantly to values >100 days in the outer shelf, indicating that riverine (Pearl River) DOC might be more labile. The actual mechanism for this is unknown, but might relate to higher inorganic nutrient supply from river/terrestrial sources. The positive correlation of the BP / PP ratios vs. phosphate (and nitrate) concentrations in the inner shelf implies that if anthropogenic mineral loading keeps increasing in the foreseeable future, the near-shore zone may become more heterotrophic, rendering the system a stronger source of CO2.
Effects of heat and drought on carbon and water dynamics in a regenerating semi-arid pine forest: a combined experimental and modeling approach
Authors: Ruehr N. K. , Law B. E. , Quandt D. , Williams M.
Published: January 2014

Abstract. Increasing summer temperatures and a reduction in precipitation will enhance drought stress in Mediterranean and semi-arid ecosystems. Predicting the net effects on forests' carbon and water balance will depend on our ability to disentangle the sensitivity of component fluxes responding to increasing soil and atmospheric drought. Here we studied carbon and water dynamics in a semi-arid regenerating ponderosa pine forest using field observations and process based modeling. Field observations of two summer dry seasons were used to calibrate a soil-plant-atmosphere (SPA) model. In addition, the ecosystem's response to reduced soil drought was quantified based on a field watering experiment and evaluated with the model. Further, the SPA model was used to estimate the relative effects of increasing soil and atmospheric drought over time, by simulating temperature and precipitation scenarios for 2040 and 2080. The seasonality and drought response of ecosystem fluxes was well captured by the calibrated SPA model. Dramatic increases in summer water availability during seasonal drought had a small effect on pine physiology in both the watering experiment and the model. This clearly demonstrates that atmospheric drought induced a strong limitation on carbon uptake in young ponderosa pine due to tight regulation of stomatal conductance. Moreover, simulations showed that net ecosystem exchange (NEE) and gross primary productivity (GPP) were about three times more affected by summer heat and increased evaporative demand than by reductions in summer precipitation. Annual NEE decreased by 38% in response to extreme summer conditions as predicted to occur in 2080 (June–August: +4.5 °C), because of a strong decline in GPP (−17%) while heterotrophic respiration was relatively unaffected (−1%). Considering warming trends across all seasons (September–May: +3 °C and June–August: +4.5 °C), the negative drought effects were largely compensated by an earlier initiation of favorable growing conditions and bud break, enhancing early season GPP and needle biomass. An adverse effect, triggered by changes in early season allocation patterns, was the decline of wood and root biomass. This imbalance may increase water stress over the long-term to a threshold at which ponderosa pine may not survive, and highlights the need for an integrated process understanding of the combined effects of trends and extremes.
Optimizing sample pretreatment for compound-specific stable carbon isotopic analysis of amino sugars in marine sediment
Authors: Zhu R. , Lin Y.-S. , Lipp J. S. , Meador T. B. , Hinrichs K.-U.
Published: January 2014

Abstract. Amino sugars are quantitatively significant constituents of soil and marine sediment, but their sources and turnover in environmental samples remain poorly understood. The stable carbon isotopic composition of amino sugars can provide information on the lifestyles of their source organisms and can be monitored during incubations with labeled substrates to estimate the turnover rates of microbial populations. However, until now, such investigation has been carried out only with soil samples, partly because of the much lower abundance of amino sugars in marine environments. We therefore optimized a procedure for compound-specific isotopic analysis of amino sugars in marine sediment employing gas chromatography-isotope ratio mass spectrometry. The whole procedure consisted of hydrolysis, neutralization, enrichment, and derivatization of amino sugars. Except for the derivatization step, the protocol introduced negligible isotopic fractionation, and the minimum requirement of amino sugar for isotopic analysis was 20 ng, i.e. equivalent to ~ 8 ng of amino sugar carbon. Our results obtained from δ13C analysis of amino sugars in selected marine sediment samples showed that muramic acid had isotopic imprints from indigenous bacterial activities, whereas glucosamine and galactosamine were mainly derived from organic detritus. The analysis of stable carbon isotopic compositions of amino sugars opens a promising window for the investigation of microbial metabolisms in marine sediments and the deep marine biosphere.
Ensemble projections of future streamflow droughts in Europe
Authors: Forzieri G. , Feyen L. , Rojas R. , Flörke M. , Wimmer F. , Bianchi A.
Published: January 2014

Abstract. There is growing concern in Europe about the possible rise in the severity and frequency of extreme drought events as a manifestation of climate change. In order to plan suitable adaptation strategies it is important for decision makers to know how drought conditions will develop at regional scales. This paper therefore addresses the issue of future developments in streamflow drought characteristics across Europe. Through offline coupling of a hydrological model with an ensemble of bias-corrected climate simulations (IPCC SRES A1B) and a water use scenario (Economy First), long-term (1961–2100) ensemble streamflow simulations are generated that account for changes in climate, and the uncertainty therein, and in water consumption. Using extreme value analysis we derive minimum flow and deficit indices and evaluate how the magnitude and severity of low-flow conditions may evolve throughout the 21st century. This analysis shows that streamflow droughts will become more severe and persistent in many parts of Europe due to climate change, except for northern and northeastern parts of Europe. In particular, southern regions will face strong reductions in low flows. Future water use will aggravate the situation by 10–30% in southern Europe, whereas in some sub-regions in western, central and eastern Europe a climate-driven signal of reduced droughts may be reversed due to intensive water use. The multi-model ensemble projections of more frequent and severe streamflow droughts in the south and decreasing drought hazard in the north are highly significant, while the projected changes are more dissonant in a transition zone in between.
Four-dimensional energy spectrum for space–time structure of plasma turbulence
Authors: Narita Y.
Published: January 2014

Abstract. A parametric model of the inertial-range energy spectrum is constructed for plasma turbulence in the four-dimensional wave vector and frequency domain. The model is based on that of the Eulerian wavenumber-frequency spectrum developed for describing fluid turbulence, and includes wave vector anisotropies in the three-dimensional wave vector domain by approximating the spectrum to a set of ellipses. The shape of the four-dimensional spectrum is determined by the Doppler shift, the Doppler broadening, and anisotropy coefficients. The model is applied to the magnetic energy spectrum in the near-Earth solar wind measured by four Cluster spacecraft, and the set of the spectral parameters are determined observationally. In this way, space–time structure of plasma turbulence can be condensed into a small number of parameters, which is suitable for evaluating the energy spectra in observational and numerical studies on the quantitative basis.
Sensory Acceptability of Sorghum Peanut Blend (SPB) and Corn Soy Blend Plus (CSB+) By Young Children With Moderate Acute Malnutrition in Karamoja, Uganda
Authors: Amegovu Andrew Kiri , Ogwok Patrick , Ochola Sophie , Yiga Peter , Musalima Juliet Hatoho , Mandha Juliana
Published: January 2014

Sorghum peanut blend (SPB) and corn soy blend plus (CSB+) are highly nutritious supplementary food products. SPB is formulated using local food items while CSB+ is a traditional product donated by World Food Programme to malnourished children in Uganda. The acceptability of SPB and CSB+ among children and caretakers was studied in northeastern Uganda. A 5-point hedonic scale was used to evaluate the caretakers’ sensory preferences for the two supplementary diets. A four-day central tasting, two weeks home use trial, and exit interviews were carried out. Sensory attributes of both food supplements had a rank of > 4. Taste varied (P < 0.05) with the food type. CSB+ had a higher (P < 0.05) taste score than SPB. Other attributes were not statistically different. During central tasting, about 100% of the served porridge was consumed by the children. Feeding duration of 300 mL of porridge was 8.14 min for CSB+ and 8.24 min for SPB. Over the two weeks home use trial, 98.4% of SPB and 98.1% of CSB+ of the provided rations were consumed. The quantities of food consumed were above the recommended acceptability level of ? 75%. Reported allergic and intolerance cases were below the 10% threshold. Both food supplements were found to be acceptable to children.
La ética olvidada: El valor comercial de los espacios informativos de la televisión en España
Authors:   Universidad Rey Juan Carlos (España), Santín Durán Marina
Published: January 2014

Este artículo pone de manifiesto que los noticiarios, los programas emblemáticos de servicio público de las cadenas, han cedido a las presiones comerciales del medio y han introducido prácticas poco legítimas en el quehacer informativo. El análisis de los informativos de las principales cadenas privadas de televisión en España evidencia una ruptura de la frontera entre publicidad y periodismo. La información audiovisual –muestra este trabajo– ha quedado contaminada por las prácticas comerciales publicitarias y las noticias autorreferentes que persiguen fines autopromocionales.
De Betty, la fea a Ugly Betty. Circulación y adaptación de narrativas televisivas
Authors:   Universidad del Mar Campus Huatulco e Instituto de la Comunicación Santa Cruz Huatulco, Oaxaca (México), Murillo Sandoval Sandra , Escala Rabadán Luis ,   El Colegio de la Frontera Norte. Departamento de Estudios Culturales. Tijuana, Baja California (México)
Published: January 2014

En este artículo se examina la adaptación de la telenovela colombiana Yo soy Betty, la fea al serial estadounidense Ugly Betty, con el propósito de examinar el proceso de construcción simbólica de la fealdad a partir de la condición étnica de su personaje central. Para ello, se evalúa el discurso desarrollado a través de dicho personaje, Betty Suárez, que sirve como vehículo para elaborar una narrativa de identidad nacional sobre la población latina en Estados Unidos. La serie permite visualizar la propuesta televisiva de una sociedad figurada que constituye una alternativa de construcción simbólica de un grupo social como el latino. A través del análisis narrativo se explica la reformulación de las oposiciones simbólicas en ambos mundos (latino y anglo) lo cual dará paso a la paulatina aceptación de Betty no solamente en términos de su no-belleza física, sino también de su condición étnica y social.
El impacto del rating televisivo sobre la actividad en Twitter: evidencia para Chile sobre la base del evento Teletón 2012
Authors:   Universidad Adolfo Ibáñez (Chile), Fábrega Jorge , Vega George ,   NodosChile (Chile)
Published: January 2014

¿Tiene un impacto el rating televisivo sobre el volumen de actividad en Twitter? El surgimiento de medios sociales vía Internet está modificando las prácticas en la industria televisiva. En particular, los canales de televisión están integrando en sus programaciones de forma explícita la interacción con las audiencias vía medios sociales. Estos esfuerzos se están realizando motivados más por la intuición que por evidencia respecto a la eficacia de los mismos. Para contribuir a identificar el real impacto de los contenidos televisivos sobre la actividad en el medio social Twitter, este estudio propone el análisis estadístico de la relación entre rating televisivo y actividad en Twitter durante la transmisión de un mismo evento por todos los canales de televisión, la Teletón 2012. Los resultados sugieren la existencia de un impacto positivo y estadísticamente significativo que vincula el rating televisivo con la actividad en Twitter. Específicamente, durante el evento Teletón 2012, un aumento de un 1 punto del rating televisivo significó incrementos promedios de 1.5 tweets por minuto para el conjunto de la transmisión y de 6 tweets por minuto en horario prime.
Montane forest root growth and soil organic layer depth as potential factors stabilizing Cenozoic global change
Authors: Doughty Christopher E. , Taylor Lyla L. , Girardin Cecile A. J. , Malhi Yadvinder , Beerling David J.
Published: January 2014

Tree roots and their symbiotic fungal partners are believed to play a major role in regulating long‐term global climate, but feedbacks between global temperature and biotic weathering have not yet been explored in detail. In situ field data from a 3000 m altitudinal transect in Peru show fine root growth decreases and organic layer depth increases with the cooler temperatures that prevail at increased altitude. We hypothesize that this observation suggests a negative feedback: as global temperatures rise, the soil organic layer will shrink, and more roots will grow in the mineral layer, thereby accelerating weathering and reducing atmospheric CO2. We examine this mechanism with a process‐based biological weathering model and demonstrate that this negative feedback could have contributed to moderating long‐term global Cenozoic climate during major Cenozoic CO2 changes linked to volcanic degassing and tectonic uplift events.
Surface of Ligeia Mare, Titan, from Cassini altimeter and radiometer analysis
Authors: Zebker Howard , Hayes Alex , Janssen Mike , Le Gall Alice , Lorenz Ralph , Wye Lauren
Published: January 2014

Cassini radar observations of the surface of Ligeia Mare collected during the 23 May 2013 (T91) Cassini flyby show that it is extremely smooth, likely to be mostly methane in composition, and exhibits no surface wave activity. The radar parameters were tuned for nadir‐looking geometry of liquid surfaces, using experience from Cassini's only comparable observation, of Ontario Lacus on 21 December 2008 (T49), and also include coincident radiometric observations. Radar echoes from both passes show very strong specular radar reflections and limit surface height variations to 1 mm rms. The surface physical temperature at 80°N is 92 +/− 0.5 K if the sea is liquid hydrocarbon and the land is solid hydrocarbon, essentially the same as Cassini CIRS measurements. Furthermore, radiometry measurements over the surrounding terrain suggest dielectric constants from 2.2 to 2.4, arguing against significant surface water ice unless it is extremely porous.