Primary results of sedimetological research on the upper Jurassic to lower Cretaceous carbonate rocks in NW Zagros Mountains, Iran

The upper Jurassic-lower Cretaceous carbonate extensively distributed in Zagros Mountains (southern Iran) is correlated to hydrocarbon reservoir rocks, however has not been studied with sedimentological aspects. The studied section of about 1000 m thick exposed in Kuh-d-Yaghma (Aligdaz Province) mainly consists of shallow marine facies exhibiting sedimentary structures, such as paleosols, paleokarsts, biostromes, and stromatolites. The section was subdivided into nine units based on the results of observation of outcrops and thin sections. Depositional ages were estimated by fossil occurrences and strontium stable isotope. Units 1 and 2 represent subaerial-meteoric diagenetic structures (paleosols. paleokarsts, and banded cements) and dolomite of a mixed-water origin. Originally, the dolostone was highly-permeable coarse-grained sediment, in which dolomitization selectively subjected. These diagenetic processes may have been associated with global sea-level low or a regional tectonic event during Kimmeridgian, and formed lithified substrate, which is suitable for sedentary organisms. Unit 3 abundantly yields potential reef-building organisms, such as stromatoporoids, corals, and calcareous algae. However, the dominant constituents are broken uniserial branching stromatoporoids, their constructions should be regarded as biostromes and did not form reef framework. Fossil association and strontium isotopic ratio indicate that this unit was deposited in Tithonian. Units 4～7 are alternations of two deeper and two shallower facies. The deeper units (units 4 and 6) mainly consists of micritic limestone with biofacies characterized by ostracodes, bryozoans, and sponge spicules. The shallower units (units 5 and 7) represents stromatolites, oncoids, and ooids with rich assemblage of calcareous algae. Jurassic/Cretaceous boundary was placed in unit 5. First appearance of orbitolinid foraminifers at the base of unit 7 was interpreted to correspond to the base of Barremian. Units 8 and 9 consist of four upward-shallowing sequences. The base of each cycle consists of thinly bedded limestone containing brachiopod shell, and change into thickly bedded and massive limestone with shallow marine stromatolies and fauna, such as corals and rudists. Gradual decrease in thickness of the sequence indicates that the platform was in progradation due to accumulation of the carbonate deposits

Dispersion Behavior of Magnetic Iron Oxide in Organic Slurry Containing Fatty Acids

Dispersion of magnetic iron oxide powder, γ-Fe2O3 in the mixture of toluene and cyclohexane was studied to decrease the viscosity of the slurry and prepare the stable slurry in the presence of some saturated fatty acids with a straight chain as dispersing agents. The dispersion of γ-Fe2O3 is controlled by the steric hindrance of the dispersing agent adsorbed on it. Therefore, the viscosity and dispersion of the slurry significantly depend on the carbon number and the amount of the fatty acids. Since water content of γ-Fe2O3 greatly influences the control of the viscosity and dispersion degree, low water content is required to get lower viscosity and more stable dispersed state. The four measurements to evaluate slurry flow characteristics, namely viscosity, yield stress, sedimentation volume and particle size measurements, can become a standard method to estimate the degree of flocculation and dispersion of particles in solvents

Solvent Extraction of Copper from Chloride Solution with 2-Ethylhexanal Oxime

There has been a trend to switch from pyrometallurgy to hydrometallurgy in copper refining of copper sulphide ores since pyrometallurgy process needs a huge amount of energy and is harmful to the environment. In this study, focusing on the extraction selectivity of EHO (2-ethylhexanal oxime), which extracts Cu, Ni and Pd from chloride solution, the mechanism and behavior of Cu2+ extraction with EHO from the leached solution of copper sulphide ores with ferric chloride solution and stripping of copper with water were investigated in order to clarify the possibility of an environmentally friendly hydrometallurgical process. The EHO extracts Cu2+ selectively from the chloride solution and the extraction reaction is a solvation type as follows ; Cu2+aq + 2Cl-aq + EHOorg＝CuCl2・2EHOorg The extractant does not extract other metal ions such as Zn2+, Fe2+ and Fe3+, which are the main impurities in the leached solution. It was also found that the extraction is an exothermic reaction of ΔH=-130kJ/mol and the stripping reaction is endothermic with the reaction heat of ΔH=43kJ/mol

DISPERSION AND FLOCCULATION OF α-Al2O3 IN AQUEOUS SOLUTION CONTAINING HYDROPHILIC POLYMERS

The effect of polyacrylic acid on the dispersion and flocculation behavior of Al2O3 in aqueous solution was investigated. The stability of Al203　suspension was evaluated from the measurements of average particle size, turbidity, sedimentation volume and viscosity. The dispersion and flocculation behavior of Al2O3 was explained by measuring the adsorption amount of the polyacrylic acid and the zeta potential of Al203. When the adsorption of polyacrylic acid on Al203 is saturated, the dispersion of Al203 is enhanced. It is evident that the conformation of the polymer is a controlling factor in determining the stability of Al203 particles. The addition of polyacrylic acid with a molecular weight of 6000 gives the best dispersion state among the various polyacrylic acids of different molecular weights used in our experiments

Solvent Extraction of Copper from Chloride Solution for Environmentally Friendly Copper Hydrometallurgical Process

The present refining of copper from sulfide copper ores by pyrometallurgical process is lack for the environmental concerns, that is, generation of harmful SO2 gas and high energy consumption. Considering our environmental aspect and saving the energy, we directed our attention to recover Cu by using the more advantageous L-SX=EW (Leaching-Solvent Extraction-Electrowinning) method. This hydrometallurgical L-SX-EW method can be designed as a closed system and lessen the wastes from the process. Based on the investigation we have already reported with respect to the extraction mechanism of Cu2+ with EHO (2-ethylhexanal oxime), in this study the separation of Cu2+ was examined from the leached solution obtained after leaching copper sulfide ores with ferric chloride solution, and the realizability of the environmentally friendly hydrometallurgical process was also investigated. The extractant EHO is very effective to separate Cu2+ from the leached solution containing Fe2+, Fe3+ and Zn2+. Cupric ions are selectively extracted in the organic phase at chloride ion concentration, 3～5 mol/dm3, while Fe3+ and Zn2+ are not transferred into the organic phase. The stages and phase ratio (A/O) required to attain the desired Cu2+ recovery are estimated to be 2-stage countercurrent extraction with the phase ratio (A/O) of 1.5. In order to strip Cu with water from the organic phase, 6-stages countercurrent stripping with the phase ratio (O/A) of 1.8 are required. By the extraction and stripping operation, 10 g/dm3Cu2+ is purified and concentrated to 25 g/dm3 Cu2+

CHEMICAL FIXATION OF CARBON DIOXIDE USING SOLVENT EXTRACTION

Investigations were carried out to create a chemical fixation process, where carbon dioxide and sodium chloride solution are converted to sodium hydrogen carbonate and hydrochloric acid. Because the reaction has a large and positive free energy change, it does not proceed unless a suitable condition is established.The reaction is able to proceed if hydrochloric acid，which is one of the reaction products，is removed from the reaction system by extraction with amine.Stripping of hydrochloric acid from the organic phase containing amine hydrochloride is very difficult, due to the high chemical stability of amine hydrochloride. The stripping is accomplished by using a mixed aqueous-organic media as a stripping agent. This paper proposes both a total process and a process flow for the chemical fixation of carbon dioxide

STUDIES OF SEPARATION BEHAVIOR AND MECHANISM OF PLASTICS, PVC AND PET, BY FLOTATION METHOD

Heretofore, waste disposal by combustion or reclamation treatment has been prevalent. Since plastic is a very convenient material, the amount of waste plastic has been increasing without establishment of a particular recycling method for it.Recycling not only decreases wastes, but protects our environment, too. PVC (polyvinyl chloride) especially generates terrible toxic gases such as dioxin, chlorine and hydrochloride during the combustion process. As both PVC and PET (polyethylene terephthalate) have similar chemical and physical properties(hydrophobicity, specific gravity, etc), it is very difficult to separate them

FLOW CHARACTERISTICS of r-Fe203-HYDROCARBON SLURRY IN THE PRESENCE OF VARIOUS FATTY ACIDS

The effect of some fatty acids on the flocculation and dispersion properties of r-Fe203 particles in magnetic slurry was investigated. For preparation of the magnetic slurries in this experiments, r-Fe203 powders, some straight chained fatty acids with carbon numbers of C9-C21 in the alkyl chain and toluene-cyclohexane solution were used. The rheological properties of the slurry，namely the flow curve，yield stress and sedimentation volume of the r-Fe203 slurry were measured. It was found that the flow characteristics of the slurry varies depending on the alkyl chain length for each fatty acid added. The addition of stearic acid gives the best dispersion in our experimental trials. From the result of the calculation of the energy acting between particles，it was found that r-Fe203 particles in the slurry have a strongly magnetic attractive force

Continuous versus intermittent antibiotics for bronchiectasis

Background Bronchiectasis is a chronic airway disease characterised by a destructive cycle of recurrent airway infection, inflammation and tissue damage. Antibiotics are a main treatment for bronchiectasis. The aim of continuous therapy with prophylactic antibiotics is to suppress bacterial load, but bacteria may become resistant to the antibiotic, leading to a loss of effectiveness. On the other hand, intermittent prophylactic antibiotics, given over a predefined duration and interval, may reduce antibiotic selection pressure and reduce or prevent the development of resistance. This systematic review aimed to evaluate the current evidence for studies comparing continuous versus intermittent administration of antibiotic treatment in bronchiectasis in terms of clinical efficacy, the emergence of resistance and serious adverse events. Objectives To evaluate the effectiveness of continuous versus intermittent antibiotics in the treatment of adults and children with bronchiectasis, using the primary outcomes of exacerbations, antibiotic resistance and serious adverse events. Search methods On 1 August 2017 and 4 May 2018 we searched the Cochrane Airways Review Group Specialised Register (CAGR), CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, and AMED. On 25 September 2017 and 4 May 2018 we also searched www.clinicaltrials.gov, the World Health Organization (WHO) trials portal, conference proceedings and the reference lists of existing systematic reviews. Selection criteria We planned to include randomised controlled trials (RCTs) of adults or children with bronchiectasis that compared continuous versus intermittent administration of long-term prophylactic antibiotics of at least three months' duration. We considered eligible studies reported as full-text articles, as abstracts only and unpublished data. Data collection and analysis Two review authors independently screened the search results and full-text reports. Main results We identified 268 unique records. Of these we retrieved and examined 126 full-text reports, representing 114 studies, but none of these studies met our inclusion criteria. Authors' conclusions No randomised controlled trials have compared the effectiveness and risks of continuous antibiotic therapy versus intermittent antibiotic therapy for bronchiectasis. High-quality clinical trials are needed to establish which of these interventions is more effective for reducing the frequency and duration of exacerbations, antibiotic resistance and the occurrence of serious adverse events. Plain language summary Are antibiotics more effective when given continuously or intermittently to people with bronchiectasis? Background Bronchiectasis is an incurable lung disease characterised by repeated chest infections. Antibiotics are a main form of treatment and can be taken long term to prevent chest infections from developing. This could be continuously or intermittently for a fixed period of time. However, we do not currently know which approach is the most effective for reducing the frequency and duration of exacerbations, managing antibiotic resistance and minimising side effects. Study Characteristics On 1 August 2017 we searched a wide range of sources to find clinical trials for our review. We found 268 potentially relevant results but on closer examination none of the studies met our review criteria and none could be included. Authors' conclusions There is no high-quality evidence about whether continuously administered or intermittently administered antibiotics are safer and more helpful for people with bronchiectasis. More research is needed to evaluate which one of these methods is better for reducing chest infections, limiting resistance to antibiotic therapy and reducing serious side effects