bluuebunny/crossref_metadata_2025 huggingface dataset:
The Corrosion Resistance of Ductile Iron In Sea Water and Petroleum Tanker Services★
Authors: PARIS MICHEL , de la BRUNIERE B.
Published: July 2014

Laboratory data are given which compare the corrosion resistance of gray iron, steel and ductile iron in sea water and various acid solutions of different concentrations. Data also are presented to show the performance of ductile iron when used for product lines on petroleum tankers. Of particular interest is information presented for a low alloyed ductile iron which has given complete satisfaction under highly aggressive conditions in petroleum tanker service. 6.2.2
Control of Corrosion with Zinc Coatings★
Authors: KIMBERLEY J. L
Published: July 2014

A history of the uses of metallic zinc and zinc coatings to control corrosion is outlined briefly with some consideration being given to the theory under which zinc is protective to steel. The following methods of application of zinc are discussed in detail: hot dip, metallizing, sherardizing and painting. The relative merits and weaknesses of zinc coats are considered with case histories being cited to show the fields of usefulness of such coatings. 5.3.2
Some Aspects of the Corrosion Processes of Iron, Copper And Aluminum in Ethylene Glycol Coolant Fluids
Authors: THOMPSON P. F. , LORKING K. F.
Published: July 2014

The corrosion potentials of aluminum, iron and copper, the principal metals in coolant systems, were measured in glycol-water solutions. The effect on the corrosion properties of these metals of the addition of triethanolamine phosphate, formerly used as a corrosion inhibitor in glycol coolants, was studied. It was shown that the copper ions produced by corrosion of copper are stabilized by triethanolamine phosphate. The copper went into solution as a blue cuprammine complex, which remained stable until it reached iron or aluminum surfaces where it was deposited, causing localized corrosion. 4.4.3
Resistance to Corrosion of Aluminum Alloys For Automotive Applications★
Authors: ENGLEHART E. T. , COCHRAN W. C. , WHITE E. P.
Published: July 2014

Aluminum alloys have been employed in automobiles for some time in applications such as pistons. In recent years, however, increased use of aluminum alloys for many other automotive applications has been anticipated. This paper presents the available information on the resistance to corrosion of aluminum alloys for these many new uses. Particular emphasis has been placed on performance of aluminum alloys for automotive trim, but other applications are also covered. Included is a discussion of choice of alloy and the performance of the large variety of finishes available. Results of atmospheric corrosion tests together with those of limited field experience are provided to indicate the good resistance to corrosion of aluminum alloys in these applications. Factors affecting the performance of these alloys in service are also covered. 6.4.2
Water Conditions for High Pressure Boilers
Authors: VOYLES D. E. , FISS E. C.
Published: July 2014

Components of a high pressure boiler system which are in contact with high purity water are described. Materials of construction and operating pressures and temperatures are given for such items as condensers, feedwater heaters and boiler components. Demineralized and evaporated make-up are referred to along with data on the chemical nature of the water. Analyses of water and steam samples from points in the boiler water cycle show iron and copper contents and other indications of the purity and corrosiveness of the water. The part played by chemical treatment, boiler blowdown, removal of dissolved gases and other operating factors in maintaining the described water conditions are discussed. 4.6.2
The Oxidation of Molybdenum★
Authors: JONES E. S. , MOSHER CAPT. J. F. , SPEISER RUDOLPH , SPRETNAK J. W.
Published: July 2014

Scale formed upon molybdenum consists of either two or three oxide layers., depending upon temperature and time. The outermost layer is the volatile MoO3. The inner layers of oxide have a composition very close to MoO2 but do not exhibit an X-ray pattern corresponding to MoO2.

The rate of evaporation of MoO3 and the mechanism of molybdenum oxidation were determined. It was found that after an initial parabolic dependence of weight change upon time the rate of oxidation became linear. This is due to the fact that the outer MoO3 layer is non-protective so that the rate of oxidation of the suboxide to the trioxide at the suboxide-trioxide interface is equal to the rate of diffusion of oxygen through the suboxide film to the metal-suboxide interface. It was also found that the presence of liquid MoO3 increased the rate of oxidation of molybdenum. 6.3.9
Current and Potential Relations for The Cathodic Protection of Steel in Salt Water★
Authors: SCHWERDTFEGER W. J.
Published: July 2014

A laboratory investigation was made pertaining to the cathodic protection of steel specimens that were exposed for 60 days to both stagnant and aerated city water, to which was added 3 percent by weight of sodium chloride.

Major consideration was given to the significance of potential as a criterion for protection. Optimum protection was achieved when specimens were controlled at —0.77 volt with reference to the saturated calomel half cell. Although a good degree of protection was obtained at controlled potentials more noble than —0.77 volt, that is, at the potentials associated with the breaks in cathodic polarization curves, this lesser degree of protection could not be obtained at lower mean current densities. 5.2.4
Evaluation of Refinery Corrosion inhibitors★
Authors: FREEDMAN A. J. , DRAVNIEKS A.
Published: July 2014

Since reproduction of refinery operating conditions in the laboratory is difficult, most laboratory testing of refinery corrosion inhibitors has been unreliable. For this reason,, inhibitors for refinery use have been selected mainly on the basis of qualitative field trials. Such tests are expensive and subject to many independent, noncontrollable variables.

Frequently, failures of corrosion inhibitors to provide satisfactory protection can be traced to specific environmental factors. Therefore, new laboratory tests for commercial refinery corrosion inhibitors have been developed to simulate closely certain features of actual field conditions. Inhibitors have been evaluated for corrosion protection in light naphtha condensers, distillation towers, special high temperature locations, high velocity service, narrow crevices, and for impingement attack.

These test data show conclusively that no single corrosion inhibitor can be expected to provide satisfactory corrosion protection in all refinery locations. Plant results obtained with electrical resistance corrosion probes corroborate the laboratory evaluations. 5.8.1
An Electrical Resistance Method of Corrosion Monitoring In Refinery Equipment★
Authors: FREEDMAN A. J. , TROSCINSKI E. S. , DRAVNIEKS A.
Published: July 2014

A corrosion test system based on the electrical resistance method permits continuous monitoring of corrosion rates in refinery equipment without interrupting normal operations. Corrosion decreases the cross-section, and consequently the electrical conductivity, of a metal specimen exposed to refinery fluids at high temperatures and inaccessible locations. From the decrease in conductivity, or increase in resistance, the amount of corrosion which occurs between measurements can be determined. The system has been used successfully under all conditions of temperature and pressure encountered in a refinery. It has measured corrosion rates in vapor and liquid phases, with both oil and aqueous media.

With the aid of the corrosion probe, corrosion rates in operating refinery equipment have been determined quantitatively in a few hours' time, as compared with months required for coupon measurements, water analyses, and unit inspections. Refinery corrosion inhibitors have been compared rapidly in actual use. Effects of changes in unit operating procedures upon corrosion rates have been observed shortly after the changes were made. Sensitive locations where corrosion is expected have been monitored frequently. 2.2.1
Corrosion Rates of Mild Steel In NH4NO3-NH3-H2O Solutions★
Authors: HACKERMAN NORMAN , HURD RAY M. , SNAVELY EARL S.
Published: July 2014

Corrosion rates of mild steel in mixtures of NH4NO3-NH3-H2O were measured at temperatures of 30, 45 and 60 C. The effects of various sulfur and arsenic-containing inhibitors were studied, with particular emphasis on NH4CNS. The corrosion reaction was found to be markedly affected by stresses in the metal to the extent that completely stress-relieved coupons would not corrode at all. The rate of the uninhibited reaction was much lower at 45 and 60 C than at 30 C, indicating a change in the mechanism of the corrosion reaction.

The uninhibited corrosion rate of 3700 mdd at 30 C was decreased to approximately 25 mdd with NH4CNS concentrations greater than 0.1 percent. At 45 C, the most effective inhibitor was found to be 0.05 percent 2-mercapto-ethanol + 0.05 percent sodium arsenite, followed closely by 0.1 percent NH4CNS + 0.05 percent sodium arsenite. Thio-cyanate and thiourea alone at concentrations of 0.1 percent were somewhat less effective.

Simple potential measurements using a platinum reference electrode showed the corroding coupons to be about 0.9 volt more anodic than the stress-relieved coupons. 4.3.4
The Behavior of Steels in Hydrogen Sulfide Environments★
Authors: VOLLMER L W.
Published: July 2014

Spontaneous cracking of steels in deep high-pressure condensate wells producing gas containing hydrogen sulfide has been a subject for considerable investigation during the past seven or eight years. This paper presents: (1) a definition and possible mechanisms for sulfide-stress cracking of steels, (2) the methods currently being used to establish the susceptibility of steels to this phenomenon, (3) a brief summation of the significant developments from research on the problem, and (4) the measures that are currently indicated to minimize the possibilities of such failures in steel equipment.

The term “sulfide-stress cracking” is preferred to the commonly used “sulfide corrosion cracking” since the phenomenon is stress dependent.

The susceptibility of most constructural steels to sulfide-stress cracking can be minimized, if not eliminated, by appropriate heat treatment which must include tempering at a temperature not less than 1150 F and by limiting the maximum mechanical properties to predetermined levels. When the use of high strength metals is unavoidable, certain nonferrous alloys, which thus far have indicated a high degree of insensitivity to the phenomenon, are suggested. 3.2.2
Corrosion Resistance of Titanium Alloys Compared With Commercially Pure Titanium
Authors: SCHLAIN DAVID , KENAHAN CHARLES B.
Published: July 2014

Titanium-8 percent manganese, titanium-5 percent aluminum-2½ percent tin, titanium-2 percent aluminum, titanium-6 percent aluminum, titanium-1 percent copper, and titanium-5 percent copper alloys are similar to commercially pure titanium in chemical and galvanic corrosion properties. These alloys are completely resistant to corrosion in synthetic ocean water, tap water, 1 percent sodium hydroxide, and 5 percent ferric chloride solutions. In sulfuric acid solutions saturated with air, the titanium alloys with the exception of those containing copper are resistant to corrosion in 5 percent solution at 35 C but corrode rapidly in 10 percent solution. At 60 C, these alloys are inert in 1 percent and corrode in 5 percent acid. The titanium-copper alloys usually are more resistant than commercially pure titanium to corrosion in sulfuric acid solutions and less resistant in hydrochloric acid. In contact with aluminum in 0.5 percent sulfuric acid saturated with air, titanium and the titanium-base alloys are the cathodic members of the couples. Titanium and titanium-base alloys are generally anodic when in contact with stainless steels in air-saturated 4.7, 9.3 and 17.5 percent sulfuric acid solutions but the galvanic corrosion rates are low. Furthermore, the chemical corrosion of titanium alloys is almost eliminated as a result of contact with stainless steel. 6.3.15
Aluminum Cooling Towers and Their Treatment★
Authors: HAYGOOD A. J. , MINFORD J. DEAN
Published: July 2014

Characteristics of aluminum alloys are discussed to show the use of this material in cooling tower construction. Alloy selection, fabricating practice, surface finish and water treatment are covered. Examples of cooling tower installations and data from field research are given. 7.4.1
New Instruments and Techniques for Ultrasonic Measurement of Tank Ship Corrosion Losses★
Authors: EVANS DWIGHT J.
Published: July 2014

A method of making nondestructive thickness measurements from one side on steel, especially in tank ships, using an ultrasonic gauge,, is described. Accuracy of the “slide rule” method of calibration is detailed, and the various sources of error examined and means of compensating for them explained. Merits of the cathode ray tube resonance instrument are explained and its efficiences over earlier instruments outlined.

New techniques developed during experience in recent years are described and some changes in attitude toward earlier accepted procedures explained. Manner in which data are recorded is shown in tables. 2.4.3
Effects of Foreign Metals on Corrosion of Titanium In Boiling 2M Hydrochloric Acid
Authors: BUCK ROGER , SLOOPE BILLY W. , LEIDHEISER HENRY
Published: July 2014

The rate of corrosion of titanium was determined in boiling 2M HC1 when contacted to aluminum, cadmium, tin, zirconium, lead, bismuth, mercury, silver, copper, antimony, vanadium, 70:30, 50:50 and 30:70 copper-nickel alloys, iron, palladium, cobalt, nickel, gold, rhodium, platinum and iridium. Less extensive corrosion measurements of the same type were also made in 0.6 and 2M H2SO4. The potentials of the couple and of the two members of the couple were determined in boiling 2M HC1 for 20 of the systems studied. A plot of the corrosion rate vs the couple potential yielded a polarization curve which was similar to the anodic polarization curve for titanium with an impressed voltage. The curve exhibited a maximum in corrosion rate at a couple potential of —0.49-volt vs the saturated calomel electrode. The potential of titanium in boiling 2 M HC1 was also determined as a function of concentration of the following metallic cations in the acid: copper, silver, antimony, nickel, gold, palladium, rhodium, platinum and iridium. The influence of the cations on the corrosion rate was explained in relation to the polarization curve. 6.3.15
An Industrial Experience of Attack on Metals by Synthesis Gas From Methane-Oxygen Combustion★
Authors: EBERLE F. , WYLIE R. D.
Published: July 2014

Severe metal–wastage was experienced on AISI Type 347 (18Cr-8Ni-Nb) and AISI Type 310 (25Cr-20Ni) used in the construction of a gas generator in which methane was burned with oxygen to produce carbon monoxide and hydrogen for fuel synthesis of the Fischer-Tropsch type. The mode of attack varied with temperature. At the highest temperatures, above 1650 to 1800 F, it consisted of straight oxidation, progressing intergranularly. With decreasing temperatures, heavy carburization with occasional signs of interspersed oxidation manifested itself. As temperatures declined further, cycling carburization, oxidation and reduction were observed, accompanied by severe metal wastage.

Typically attacked metal surfaces consisted of a semi-scale containing tiny globules of metallic particles surrounded by carbon or graphite interspersed with oxide. Tests with specimens of numerous steels and alloys installed at various locations in the reactor showed that the most resistant materials were those which best resisted carburization, that is, nickel, Monelj, Inconel, AISI Type 446 (27 chrome-iron), copper, and pack-calorized materials. 4.2.3
The Evaluation of Certain Organic Nitrogen Compounds As Corrosion Inhibitors★
Authors: SCHWOEGLER E. J. , BERMAN L. U.
Published: July 2014

The Static Water Drop Test adapted to research methods has been utilized to evaluate the corrosion inhibiting ability of a number of heterocyclic nitrogen compounds. Most of these heterocyclic N derivatives were synthesized and purified and evaluated in a petroleum-type lubricating oil and a synthetic diester-type lubricating oil.

The effect of various functional groups and their positions in the molecule was related to the corrosion inhibiting properties. It was found that the adsorptive power was a function of the heterocyclic nitrogen containing a hydrogen atom as the substituent. It was also found that the adsorptive power at the heterocyclic nitrogen atom was lost when other substituents replaced the hydrogen. It was concluded that the adsorptive effect of the heterocyclic nitrogen is due to its unshared electron pair, which is sterically hindered when substituents other than hydrogen are attached.

N-Hydroxyalkyl derivatives in diester oil seemed to arrange themselves in order of effectiveness on the basis of the position of the hydroxyl group in the alkyl chain. The closer the hydroxyl was to the heterocyclic nitrogen the more effective it was as a corrosion inhibitor. There was no way to explain the order of effectiveness of the same compounds in petroleum oil. 5.8.1
High Temperature Oxidation of Chromium-Nickel Steels★
Authors: CAPLAN D. , COHEN M.
Published: July 2014

The scaling of austenitic stainless steels Type 302, 309 and 330 has been investigated by weight gain vs time measurements in air at 1600 to 2000 F and subsequent examination of the scales. As had been found previously with chromium steel, the curves exhibit breaks indicating intermediate periods of rapid oxidation due to disruption of the protective scale layer. Accumulation of silica at the metal/scale interface is found to contribute to this disruption; voids are considered to have the same effect. A distinction is drawn between such breaks and the type which arises from the extraordinary protectiveness of an initial thin oxide film, which is markedly affected by surface preparation and prior treatment. 3.2.3
Comparative Corrosion Resistance Of 200 and 300 Series Stainless Steels In Chemical Manufacturing Processes★
Authors: HAMSTEAD A. C. , VAN DELINDER L. S.
Published: July 2014

Data are presented showing the comparative corrosion resistance of several experimental heats and of two commercial heats of AISI 200 series chromium-nickel-manganese steels with the 18-8 chromium-nickel steels (300 series) in a variety of chemical manufacturing processes.

Results of this preliminary comparison have indicated that the chromium-nickel-manganese alloys may be utilized in a number of chemical services where the higher nickel compositions (18-8 steels) are now used. Some environments were encountered in chemical plant processes in which the chromium-nickel-manganese steels in the annealed condition were more corrosion resistant than the 300 series (Types 304 and 316).

In some of the plant processes tested, it was found that in the sensitized condition (1-hour at 1200 F), the susceptibility of the commercial heats of 201 and 202 to intergranular attack was greater than that of the 18-8 chromium-nickel steels. 6.25
Evaluation of Steam Resistant Coatings For Carbon Steel Hospital Ware★
Authors: BOBALEK E. G. , PARK W. R. R. , BELL E. G. , DAWSON W. R.
Published: July 2014

Steam exposure presents the most severe environment for producing blistering failure of synthetic resin coatings. Conflicting evidence has been presented over the past several years regarding the performance of modern coatings in preventing the corrosion of steel in steam exposure. Tests were made to determine the feasibility of replacing stainless steel hospital ware with coated carbon steel ware. In this connection an experimental survey was made by panel testing more than 120 commercial coatings representing about 25 different chemical types over a variety of surface treatments. Tabular comparisons were made regarding the relative worth of different types of coatings. It was found that coated mild steel could not be regarded as an adequate substitute for stainless alloys in the manufacture of sterilizers. It was discovered, though, that a number of coating types, properly applied, could withstand 500 hours or more exposure to 250 F steam. 5.4.8
Laboratory Methods for Determining Corrosion Rates Under Heat Flux Conditions★
Authors: FISHER A. O. , WHITNEY F. L
Published: July 2014

Laboratory techniques for testing the effect of heat flux and skin temperatures upon corrosion rates of 316 stainless steel, steel and cast iron in various environments are described. Advantages and disadvantages with supporting evidence are given for three practical approaches to this fundamental study in the laboratory.

Based on the data obtained, skin temperature rather than heat flux has been found to be the controlling factor in the corrosive environments investigated. Heat removed from the corroding surface through agitation and/or other methods appears to be the most practical means of increasing heat flux input without excessively increasing corrosion rate.

Preliminary results indicate the superiority of these techniques over the customary immersion tests for obtaining corrosion data involving heat transfer conditions. Continued research on these methods should eventually lead to the development of limiting skin temperatures for various metals in specific environments. Practical application of the data should form a sound basis for predicting plant corrosion rates in heat transfer equipment. 2.3.7
Evaluating The Economy of Reconditioning And Coating Underground Steel Pipe★
Authors: PEMBERTON GEORGE M.
Published: July 2014

By carefully selecting pipe for reconditioning, and accurately determining the time required for spot welding, the cost per foot for reconditioning an underground bare steel gas pipe line can be predicted. A method is developed to show that the economy of the total operation is related to this and other easily determined costs. A description of welding and wax coating methods used for an actual job is included with photographs, charts and graphs. 1.2.2
Stress Corrosion Crack Paths in Alpha Aluminum Bronze In Ammonia and Steam Atmospheres
Authors: KLEMENT J. F. , MAERSCH R. E. , TULLY P. A.
Published: July 2014

The investigation presented illustrates the importance of analyzing stress corrosion crack paths, and the interpretation of the crack paths with respect to alloys and corrosive media. Testing involved alpha aluminum bronze alloys of 5–8 percent Al content exposed to ammonia and steam atmospheres, while stressed to about 80 percent of the yield strength. The various crack paths obtained are illustrated in micrographs, and the reasons for the different types of crack paths are associated with factors such as equilibrium grain boundary segregation and the chemical attack of segregated solute elements by corrosive agents. The results of the investigation are discussed in terms of analyzing causes of field failures. Examples of processing considerations to minimize failures are cited. 3.2.2
Corrosion Protection Features Of the Hyperion Ocean Outfall★
Authors: KEELING HARRY J.
Published: July 2014

Details are presented on the planning, design and installation of corrosion protection facilities to provide 100-year design life for a 7-mile, 22-inch steel pipe sewer outfall, the outer end of which is in ocean water 340 feet deep. The outfall serves the sewerage systems of Los Angeles and 16 other adjacent municipalities.

An impressed current cathodic protection system is used to protect the exterior of the pipe which is wrapped with a multiple-layer coal tar coating reinforced with glass fiber with bonded impregnated asbestos felt shield. A reinforced pneumatically applied cement mortar jacket provides negative buoyancy. Interior is protected by centrifugally-spun mortar lining with epoxy sleeves at welded tie-in joints.

Because of the depth of water in which the pipe was to be placed several novel features were necessary. Cathodic protection was applied continuously during installation by the use of zinc anodes. This system was monitored to detect any serious coating holiday before the pipe was laid in deep water. Permanent test leads also were attached to the pipe so performance of the impressed current system could be checked, continuously.

After 1½ years' operation there has been very little change in effective coating resistance, a pipe potential of —1.05 volts versus a copper/copper sulfate electrode being maintained with consumption of about 150 ma. 5.2.3
Corrosion of Reinforcing Steel In Concrete in Marine Atmospheres★
Authors: LEWIS D. A. , COPENHAGEN W. J.
Published: July 2014

Where a reinforced concrete structure is exposed to a marine atmosphere, serious corrosion of the reinforcing steel sometimes takes place within a relatively short time and the concrete cover round the reinforcing is spalled off.

This phenomenon, examples of which are described, constitutes a major problem in South Africa, particularly in coastal areas. No exhaustive work on this particular subject is described in the literature and because of the nature of concrete, conventional methods of corrosion prevention find little direct application.

The reaction proceeds by electro-chemical mechanisms whose emf's derive from differences in pH, aeration or other factors but whose severity is influenced mainly by presence of sodium chloride in the concrete.

Accelerated corrosion tests in a salt spray cabinet using steel reinforced mortar specimens indicated that factors of considerable significance are cover to the steel, protective coatings to the mortar, and the curing, cement content and water cement ratio of the mortar. The effects of these variables in the corrosion of the steel are discussed.

A comprehensive series of both accelerated and natural exposures of reinforced concrete specimens in progress is outlined. 6.6.5
Cathodic Protection of Lead Cable Sheath★
Authors: BRUCKNER W. H. , JANSSON OLE G.
Published: July 2014

The paper describes the results of laboratory tests with gradient lead cathodes in environments of high pH level. By observation of the corrosion limit and corresponding potential it was possible to define the cathodic protection requirements for permanence of metallic lead as a function of the pH of the environment. The increment of cathodic potential required for interface protection of partially immersed lead cathodes was also defined for laboratory test cells. The effects of overprotection and of a soil barrier to diffusion are shown in the paper to increase the susceptibility of the lead system to corrosion loss during periods of minimum current supply.

The instability of a lead electrode was evident in attempts to measure static potentials except under precisely controlled conditions not obtainable in the field. It was recommended, therefore, that potentials in the field be obtained with other standards than the lead electrode. 5.2.4
Stress Corrosion Crocking of Oil Country Tubular Goods★
Authors: McGLASSON R. L. , GREAT HOUSE W. D.
Published: July 2014

Stress corrosion cracking as encountered in oil production is discussed as two problems: sulfide corrosion cracking and sweet corrosion cracking. Brief review of the literature is included.

A new test method is given which uses a notched ring loaded to different percentages of yield deformation. Also includes simple polished beam specimen test methods. Tabular data is given on hardness, applied stress and time-to-failure obtained in a saturated H2S-brine system using J-55 and N-80 steels. Concludes that any steel will suffer sulfide corrosion cracking above given hardness limits and that these limits depend on applied stress.

Tests to reproduce failures in sweet systems are reported. Conclusion is drawn that sweet cracking failures are sulfide cracking at low H2S concentrations and that time-to-failure is an inverse function of the H2S concentration. 3.2.2
Prevalence of HBV and HCV infection among multi-transfused Egyptian thalassemic patients
Authors: Mansour Ahmed Kamel , Aly Rabab Mahfouz , Abdelrazek Sohier Yahia , Elghannam Doaa Mahmoud , Abdelaziz Sherin Mohamed , Shahine Dina Abdalhalim , Elmenshawy Nadia Mohamed , Darwish Ahmad Mohamad
Published: July 2014

BACKGROUND AND OBJECTIVES:

Though regular blood transfusion improves the overall survival of patients with β-thalassemia, it carries a definite risk of infection with blood-borne viruses. The present study was carried out to estimate the real frequency of hepatitis B virus (HBV) and hepatitis C virus (HCV) among Egyptian β-thalassemic patients, and determine the infection-associated risk factors in these patients.

DESIGN AND SETTING:

A prospective study conducted in a university hospital from January 2009 to January 2010.

PATIENTS AND METHODS:

Two hundred patients with β-thalassemia major were enrolled in this study. using enzyme-linked immunoabsorbent assay (ELISA), their sera were tested for hepatitis B surface antigen (HBsAg), antibody to hepatitis C core antigen (anti-HBc), and HCV antibody (HCV Ab). The positive HCV AB results were confirmed by second generation recombinant immunoblot assay (RIBA).

RESULTS:

The study sample consisted of 111 males and 89 females, with a median age of 13 years. Eighty-one (40.5%) patients were HCV Ab positive by ELISA and 39 (19.5) were anti-HCV positive By RIBA; 58 (29.0%) were HBsAg positive and 13 (6.5%) were anti-HBc positive. Older age, an increased number of transfusion units, and HBsAg seropositivity were significantly associated with a higher prevalence of HCV and HBV.

CONCLUSION:

The prevalence of HCV and HBV infections are very high among Egyptian β-thalassemic patients, which calls for a critical look into the prevailing transfusion practices and adoption of stricter donor selection criteria to decrease the incidence rate of both HCV and HBV infections effectively. Furthermore, there is a compressing need for the use of more specific and sensitive methods for HCV testing in Mansoura university Hospitals.
Systematic analysis of tropospheric NO2 long-range transport events detected in GOME-2 satellite data
Authors: Zien A. W. , Richter A. , Hilboll A. , Blechschmidt A.-M. , Burrows J. P.
Published: July 2014

Abstract. Intercontinental long-range transport (LRT) events of NO2 relocate the effects of air pollution from emission regions to remote, pristine regions. We detect transported plumes in tropospheric NO2 columns measured by the GOME-2/MetOp-A instrument with a specialized algorithm and trace the plumes to their sources using the HYSPLIT Lagrangian transport model. With this algorithm we find 3808 LRT events over the ocean for the period 2007 to 2011. LRT events occur frequently in the mid-latitudes, emerging usually from coastal high-emission regions. In the free troposphere, plumes of NO2 can travel for several days to the polar oceanic atmosphere or to other continents. They travel along characteristic routes and originate from both continuous anthropogenic emission and emission events such as bush fires. Most NO2 LRT events occur during autumn and winter months, when meteorological conditions and emissions are most favorable. The evaluation of meteorological data shows that the observed NO2 LRT is often linked to cyclones passing over an emission region.
Single-particle characterization of the high-Arctic summertime aerosol
Authors: Sierau B. , Chang R. Y.-W. , Leck C. , Paatero J. , Lohmann U.
Published: July 2014

Abstract. Single-particle mass-spectrometric measurements were carried out in the high Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS). The instrument deployed was an aerosol time-of-flight mass spectrometer (ATOFMS) that provides information on the chemical composition of individual particles and their mixing state in real time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 and 3000 nm in diameter showed mass-spectrometric patterns, indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the high Arctic. To assess the importance of long-range particle sources for aerosol–cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest the presence of a particle type of unknown composition and source. In general, the study suffered from low counting statistics due to the overall small number of particles found in this pristine environment, the small sizes of the prevailing aerosol below the detection limit of the ATOFMS, and its low hit rate. To our knowledge, this study reports on the first in situ single-particle mass-spectrometric measurements in the marine boundary layer of the high-Arctic pack ice region.
Black carbon concentrations and sources in the marine boundary layer of the tropical Atlantic Ocean using four methodologies
Authors: Pohl K. , Cantwell M. , Herckes P. , Lohmann R.
Published: July 2014

Abstract. Combustion-derived aerosols in the marine boundary layer have been poorly studied, especially in remote environments such as the open Atlantic Ocean. The tropical Atlantic has the potential to contain a high concentration of aerosols, such as black carbon, due to the African emission plume of biomass and agricultural burning products. Atmospheric particulate matter samples across the tropical Atlantic boundary layer were collected in the summer of 2010 during the southern hemispheric dry season when open fire events were frequent in Africa and South America. The highest black carbon concentrations were detected in the Caribbean Sea and within the African plume, with a regional average of 0.6 μg m−3 for both. The lowest average concentrations were measured off the coast of South America at 0.2 to 0.3 μg m−3. Samples were quantified for black carbon using multiple methods to provide insights into the form and stability of the carbonaceous aerosols (i.e., thermally unstable organic carbon, soot like, and charcoal like). Soot-like aerosols composed up to 45% of the carbonaceous aerosols in the Caribbean Sea to as little as 4% within the African plume. Charcoal-like aerosols composed up to 29% of the carbonaceous aerosols over the oligotrophic Sargasso Sea, suggesting that non-soot-like particles could be present in significant concentrations in remote environments. To better apportion concentrations and forms of black carbon, multiple detection methods should be used, particularly in regions impacted by biomass burning emissions.
On the effects of circulation, sediment resuspension and biological incorporation by diatoms in an ocean model of aluminium*
Authors: van Hulten M. M. P. , Sterl A. , Middag R. , de Baar H. J. W. , Gehlen M. , Dutay J.-C. , Tagliabue A.
Published: July 2014

Abstract. The distribution of dissolved aluminium in the West Atlantic Ocean shows a mirror image with that of dissolved silicic acid, hinting at intricate interactions between the ocean cycling of Al and Si. The marine biogeochemistry of Al is of interest because of its potential impact on diatom opal remineralisation, hence Si availability. Furthermore, the dissolved Al concentration at the surface ocean has been used as a tracer for dust input, dust being the most important source of the bio-essential trace element iron to the ocean. Previously, the dissolved concentration of Al was simulated reasonably well with only a dust source, and scavenging by adsorption on settling biogenic debris as the only removal process. Here we explore the impacts of (i) a sediment source of Al in the Northern Hemisphere (especially north of ~ 40° N), (ii) the imposed velocity field, and (iii) biological incorporation of Al on the modelled Al distribution in the ocean. The sediment source clearly improves the model results, and using a different velocity field shows the importance of advection on the simulated Al distribution. Biological incorporation appears to be a potentially important removal process. However, conclusive independent data to constrain the Al / Si incorporation ratio by growing diatoms are missing. Therefore, this study does not provide a definitive answer to the question of the relative importance of Al removal by incorporation compared to removal by adsorptive scavenging.
Frozen ponds: production and storage of methane during the Arctic winter in a lowland tundra landscape in northern Siberia, Lena River Delta
Authors: Langer M. , Westermann S. , Walter Anthony K. M. , Wischnewski K. , Boike J.
Published: July 2014

Abstract. Lakes and ponds play a key role in the carbon cycle of permafrost ecosystems, where they are considered to be hotspots of carbon dioxide CO2 and methane CH4 emission. The strength of these emissions is, however, controlled by a variety of physical and biogeochemical processes whose responses to a warming climate are complex and only poorly understood. Small waterbodies have been attracting an increasing amount of attention since recent studies demonstrated that ponds can make a significant contribution to the CO2 and CH4 emissions of tundra ecosystems. Waterbodies also have a marked effect on the thermal state of the surrounding permafrost; during the freezing period they prolong the period of time during which thawed soil material is available for microbial decomposition. This study presents net CH4 production rates during the freezing period from ponds within a typical lowland tundra landscape in northern Siberia. Rate estimations were based on CH4 concentrations measured in surface lake ice from a variety of waterbody types. Vertical profiles along ice blocks showed an exponential increase in CH4 concentration with depth. These CH4 profiles were reproduced by a 1-D mass balance model and the net CH4 production rates then inferred through inverse modeling. Results revealed marked differences in early winter net CH4 production among various ponds. Initial state ponds underlain by stable permafrost with little or no signs of degradation yielded low net production rates, of the order of 10–11 to 10–10 mol m−2 s−1 (0.01 to 0.14 mgCH4 m−2 d−1). In contrast, advanced state ponds exhibiting clear signs of thermal erosion yielded net CH4 production rates of the order of 10–7 mol m−2 s−1 (140 mgCH4 m−2 d−1). The net production rate per square meter of advanced state ponds exceeded the maximum summer CH4 emission rates per square meter which was measured for the average tundra landscape at the study site. Our results therefore indicate that, once a particular threshold in thermal erosion has been crossed, ponds can develop into major CH4 sources. This implies that any future warming of the climate may result in non-linear CH4 emission behavior in tundra ecosystems.
ASAM v2.7: a compressible atmospheric model with a Cartesian cut cell approach
Authors: Jähn M. , Knoth O. , König M. , Vogelsberg U.
Published: July 2014

Abstract. In this work, the fully compressible, nonhydrostatic atmospheric model ASAM is presented. A cut cell approach is used to include obstacles and orography into the Cartesian grid. Discretization is realized by a mixture of finite differences and finite volumes and a state limiting is applied. An implicit time integration scheme ensures numerical stability around small cells. To make the model applicable for atmospheric problems, physical parameterizations like a Smagorinsky subgrid scale model, a two-moment bulk microphysics scheme, precipitation and vertical surface fluxes by a constant flux layer or a more complex soil model are implemented. Results for three benchmark test cases from the literature are shown. A sensitivity study regarding the development of a convective boundary layer together with island effects at Barbados is carried out to show the capability to perform real case simulations with ASAM.
Pangolin v1.0, a conservative 2-D transport model for large scale parallel calculation
Authors: Praga A. , Cariolle D. , Giraud L.
Published: July 2014

Abstract. To exploit the possibilities of parallel computers, we designed a large-scale bidimensional atmospheric transport model named Pangolin. As the basis for a future chemistry-transport model, a finite-volume approach was chosen both for mass preservation and to ease parallelization. To overcome the pole restriction on time-steps for a regular latitude-longitude grid, Pangolin uses a quasi-area-preserving reduced latitude-longitude grid. The features of the regular grid are exploited to improve parallel performances and a custom domain decomposition algorithm is presented. To assess the validity of the transport scheme, its results are compared with state-of-the-art models on analytical test cases. Finally, parallel performances are shown in terms of strong scaling and confirm the efficient scalability up to a few hundred of cores.
Hydrological recurrence as a measure for large river basin classification and process understanding
Authors: Fernandez R. , Sayama T.
Published: July 2014

Abstract. Hydrologic functions of river basins are summarized as water collection, storage and discharge, which can be characterized by the dynamics of hydrological variables including precipitation, evaporation, storage and runoff. In some situations these four variables behave more in a recurrent manner by repeating in a similar range year after year or in other situations they exhibit more randomness with higher variations year by year. The degree of recurrence in runoff is important not only for water resources management but also for hydrologic process understandings, especially in terms of how the other three variables determine the degree of recurrence in runoff. The main objective of this paper is to propose a simple hydrologic classification framework applicable to global scale and large basins based on the combinations of recurrence in the four variables. We evaluate it by Lagged Autocorrelation, Fast Fourier Transforms and Colwell's Indices of variables obtained from EU-WATCH dataset composed by eight hydrologic and land surface model outputs. By setting a threshold to define high or low recurrence in the four variables, we classify each river basin into 16 possible classes. The overview of recurrence patterns at global scale suggested that precipitation is recurrent mainly in the humid tropics, Asian Monsoon area and part of higher latitudes with oceanic influence. Recurrence in evaporation was mainly dependent on the seasonality of energy availability, typically high in the tropics, temperate and subarctic regions. Recurrence in storage at higher latitudes depends on energy/water balances and snow, while that in runoff is mostly affected by the different combinations of these three variables. According to the river basin classification 10 out of the 16 possible classes were present in the 35 largest river basins in the world. In humid tropic region, the basins belong to a class with high recurrence in all the variables, while in subtropical region many of the river basins have low recurrence. In temperate region, the energy limited or water limited in summer characterizes the recurrence in storage, but runoff exhibits generally low recurrence due to the low recurrence in precipitation. In the subarctic and arctic region, the amount of snow also influences the classes; more snow yields higher recurrence in storage and runoff. Our proposed framework follows a simple methodology that can aid in grouping river basins with similar characteristics of water, energy and storage cycles. The framework is applicable at different scales with different datasets to provide useful insights into the understanding of hydrologic regimes based on the classification.
Recognition of a porphyry system using ASTER data in Bideghan – Qom province (central of Iran)
Authors: Feizi F. , Mansouri E.
Published: July 2014

Abstract. The Bideghan area is located south of the Qom province (central of Iran). The most impressive geological features in the studied area are the Eocene sequences which are intruded by volcanic rocks with basic compositions. Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) image processing have been used for hydrothermal alteration mapping and lineaments identification in the investigated area. In this research false color composite, band ratio, Principal Component Analysis (PCA), Least Square Fit (LS-Fit) and Spectral Angel Mapping (SAM) techniques were applied on ASTER data and argillic, phyllic, Iron oxide and propylitic alteration zones were separated. Lineaments were identified by aid of false color composite, high pass filters and hill-shade DEM techniques. The results of this study demonstrate the usefulness of remote sensing method and ASTER multi-spectral data for alteration and lineament mapping. Finally, the results were confirmed by field investigation.
Parameterization of basal friction near grounding lines in a one-dimensional ice sheet model
Authors: Leguy G. R. , Asay-Davis X. S. , Lipscomb W. H.
Published: July 2014

Abstract. Ice sheets and ice shelves are linked by the transition zone, the region where flow dominated by vertical shear stress makes a transition to flow dominated by extensional stress. Adequate resolution of the transition zone is necessary for numerically accurate ice sheet–ice shelf simulations. The required resolution depends on how the basal physics is parameterized. We propose a~new, simple parameterization of the effective pressure near the grounding line, combined with an existing friction law linking effective pressure to basal stress and sliding, in a one-dimensional, fixed-grid, vertically integrated model. This parameterization represents connectivity between the basal hydrological system and the ocean in the transition zone. Our model produces a smooth transition between finite basal friction in the ice sheet and zero basal friction in the ice shelf. In a set of experiments based on the Marine Ice Sheet Model Intercomparison Project (MISMIP), we show that with a smoother basal shear stress, the model yields accurate steady-state results at a fixed-grid resolution of ~1 km.