Precious Elements Research Articles

Photoelectrochemical Behavior of Electrophoretically Deposited Hematite Thin Films Modified with Ti(IV).

Doping hematite with different elements is a common strategy to improve the electrocatalytic activity towards the water oxidation reaction, although the exact effect of these external agents is not yet clearly understood. Using a feasible electrophoretic procedure, we prepared modified hematite films by introducing in the deposition solution Ti(IV) butoxide. Photoelectrochemical performances of all the modified electrodes were superior to the unmodified one, with a 4-fold increase in the photocurrent at 0.65 V vs. SCE in 0.1 M NaOH (pH 13.3) for the 5% Ti-modified electrode, which was the best performing electrode. Subsequent functionalization with an iron-based catalyst led, at the same potential, to a photocurrent of ca. 1.5 mA·cm−2, one of the highest achieved with materials based on solution processing in the absence of precious elements. AFM, XPS, TEM and XANES analyses revealed the formation of different Ti(IV) oxide phases on the hematite surface, that can reduce surface state recombination and enhance hole injection through local surface field effects, as confirmed by electrochemical impedance analysis.

Selenium partitioning between slag and matte during smelting

Copper concentrates usually contain a number of minor as well as precious elements, the control of which in copper smelting processes is often a key to the quality of the anode copper produced and may also have a bearing on the overall economics of the process. During copper smelting, the copper concentrates are partially oxidized to form slag and matte. The molten slag and matte are separated from each other in the settler. The matte being heavier in density settles at the bottom of the furnace and slag being lighter in density floats over the matte and is eventually discarded off. During the separation, selenium is distributed between slag and matte. Selenium is a value added by-product of copper process. The lower recovery of selenium from the copper process is attributed to the high loss of selenium to the discarded slag. Knowledge of the distribution and form of selenium in slag and matte is very important in the control of the selenium loss, although to date very little is known regarding their distribution. The samples of slag and matte were collected from the smelter exit before their separation. Selenium was added in different proportions in the sample. The experiments involving slag-matte separation were performed at 1250°C for 4 hours of soaking time under inert atmosphere in a vertical tubular furnace. The distribution of selenium and the mechanism by which selenium is dissolved in matte and slag have been established by this study.

Investigation of the degradation mechanism of catalytic wires during oxidation of ammonia process

The most common catalysts for the ammonia oxidation process are 80μm diameter platinum-rhodium wires knitted or woven into the form of a gauze. In an aggressive environment and under extreme conditions (temperature 800–900°C, intensive gas flow, high pressure) precious elements are drained from the surface of the wires. Part of this separated material quickly decomposes on the surface in the form of characteristic “cauliflower-shape protrusions”. The rest of the platinum is captured by palladium-nickel catalytic-capture gauzes located beneath.In our investigation we focused on the effects of the degradation of gauzes from one industrial catalytic system. The aim of the study was to compare the degree and the mechanism of degradation of gauzes from a different part of the reactor. The study covered PtRh7 catalytic and PdNi5 catalytic-capture gauzes.X-ray computer microtomography investigation revealed that despite strong differences in morphology, each Pt-Rh wire has a similar specific surface area. This indicates that the oxidation process and morphological changes of the wires occur in a self-regulating balance, resulting in the value of the specific surface area of the catalyst. Microtomography analysis of Pd-Ni wires revealed strong redevelopment of the wires’ surface, which is related to the platinum capture phenomenon.Scanning electron microscope observations also revealed the nanostructure in the cauliflower-shape protrusions and large grains in the wires’ preserved cores. The high temperature in the reactor and the long-term nature of the process do not favor the occurrence of the nanostructure in this type of material. Further and detailed analysis of this phenomena will provide a better understanding of the precious metals etching and deposition processes during oxidation.

Contrasting the Material Chemistry of Cu2ZnSnSe4 and Cu2ZnSnS(4-x)Se x.

Earth-abundant sustainable inorganic thin-film solar cells, independent of precious elements, pivot on a marginal material phase space targeting specific compounds. Advanced materials characterization efforts are necessary to expose the roles of microstructure, chemistry, and interfaces. Herein, the earth-abundant solar cell device, Cu2ZnSnS(4-x)Se x , is reported, which shows a high abundance of secondary phases compared to similarly grown Cu2ZnSnSe4.

Voluntary Blood Donation: Attitude and Practice among Indian Adults

Background: Human blood is universally recognized as the most precious and essential element of human life. The collection of blood from voluntary, non-remunerated blood donors is an important measure for ensuring the availability and safety of blood transfusion. Adequate and safe blood supply is a demanding challenge in developing countries like India. Every year, state like Uttarakhand which is visited by lakhs of visitors during pilgrimage season and where natural calamities and accidents are very common, the availability of blood is of utmost importance. Material and Method: A quantitative approach with exploratory descriptive research design was undertaken on 198 adults by convenient sampling technique to assess the attitude and practice of adult population regarding voluntary blood donation. Attitude scale and practice checklist were used as data collection tool. Results: Result of the study shows that half of adult participants were between the age group of 18 to 29 years. More than half of the samples were females (55.1%) and majority (72.7%) of them were Hindus. Students (15.7%) and homemakers (32.3%) constituted half of the study participants. There was a statistically significant association (p=0.021) of age and attitude at the significant level of p=0.05. Conclusion: Voluntary blood donation was lacking among adult population. There was a gross difference between attitude and practice regarding blood donation. Factors associated not donation of blood were fear, pain related to needle prick, hesitation, anemia, beliefs, custom and weakness after donating. The study concluded that there is need of community awareness programs to motivate the general public for voluntary blood donation.

Atomic architectonics, nanoarchitectonics and microarchitectonics for strategies to make junk materials work as precious catalysts

In order to solve problems of limited resources and their unbalanced distributions, considerable efforts to replace precious elements with naturally abundant elements have been made using various approaches. In this highlight article, we briefly introduce several recent examples of the use of earth-abundant elements for producing environmentally friendly catalysts with performance efficiencies comparable to those made from precious metals on the basis of three types of architectonics: atomic architectonics, nanoarchitectonics, and microarchitectonics. Atomic architectonics has been applied to make highly efficient catalysts of the activation of molecular hydrogen, NO oxidation, and photo-driven water splitting with inexpensive elements through well-considered combinations and compositions of these elements. Applying nanoarchitectonics to control lattice features and produce hierarchical arrangements of “junk” materials such as CuO have made these materials catalyze the consumption of NO better than Pt catalysts and as well as Rh catalysts. Larger-scale control of morphology by applying microarchitectonics has been used to effectively avoid the agglomeration of catalyst particles and hence suppress the degradation of these catalysts as well as to minimize the use of precious-element catalysts.

Structure and water oxidation activity of 3d metal oxides

Water splitting driven by solar energy is regarded as the candidate for the next generation of power source. The reaction is however kinetically hindered by the oxygen evolution reaction (OER) involving four proton–electron transfer steps. The ideal OER catalyst should avoid using precious elements, such as Ir, Ru, and Pt, and have a long‐term stability under positive bias potential. Recent experiments have shown that most 3d oxides are OER active catalysts, while some can even achieve comparable activities to commercial Ir/Ru catalysts in lab condition. In this article, we review the recent theoretical progress for characterizing the structure of 3d oxides and understanding the photo‐electrocatalytic water splitting mechanism over these catalysts. The methodology for global structure exploration, including evolutionary algorithm and stochastic surface walking method, is first introduced together with their applications in exploring the potential energy surface of TiO2 and NiOx systems. The current theoretical approaches to investigate the thermodynamics and kinetics of photo‐/electrochemical reactions are discussed and the latest understanding for OER reactions are summarized. WIREs Comput Mol Sci 2016, 6:47–64. doi: 10.1002/wcms.1236This article is categorized under: Structure and Mechanism > Computational Materials Science Computer and Information Science > Computer Algorithms and Programming Theoretical and Physical Chemistry > Reaction Dynamics and Kinetics

Microbially Supported Recovery of Precious Metals and Rare Earth Elements from Urban Household Waste Incineration Slag

The use of precious metals and Rare Earth Elements in electronic, medical, and automobile industries is drastically increasing. To meet this demand and to escape the financial pressure of the global metal market, not only mining activities but recently also the recovery of these elements from industrial and urban household waste is in the focus of research. It has been shown that the application of extracting solutions with pH values lower than 4 lead to an economically feasible recovery of industrially precious metals. It is unclear, however, whether and to which extent this abiotic extraction efficiency can potentially be increased by using microorganisms capable of dissolving more stable minerals at low pH. The goal of this project therefore is to first view urban household waste as a resource for metals and evaluate combined abiotic and biotic extraction procedures for an increase in metal extraction efficiency.

Simulation on neonatal stabilization and transport

Legal problems are more numbered even in Neonatology. Hospital policy should establish strategies to limit systematic, environmental and human errors, including solutions to optimize organization and increase knowledge [1].Staff retraining by means of simulation could be a precious instrument. Simulation works through mechanisms that are proper of our brain for decision-making (i.e. simulated mind) [2]. The capacity of evaluating a situation earlier than it happens and so planning possible actions is the so called anticipatory simulation [3]. Physiological basis of simulation effectiveness are deeply related to mirror neurons [4]. Simulation emphasizes the so called “deutero-learning”, i.e. the context in which (proto-)learning processes occur: at the same time people are learning simple concepts, and also learning something about the world and about how things occur [5]. In sum, simulation maximises learning through the extraction of implicit rules, and putting specific bits of basic experiences in context to generalise them. The aim of this lecture is to focus on methods of simulation on neonatal stabilization and transport (more than on medical procedures themselves). Simulation retraining for medical (or nurse) staff should be based on the andragogic approach: adults are conscious of their own educational needs and focus their own attention on specific interests (related to daily practice) [6]. This methodological approach needs that teachers behave as peers towards learners, with empathy and a collaborative attitude. A precious additive methodological element is fun: the serious medical game is the approach to optimize technical memories trough emotions [5]. In our experience, materials for simulation are daily clinical devices and innovative stuff developed by a multidisciplinary collaboration [7];we discuss published guidelines (e.g. STABLE Program) and participants’ experiences. As regards neonatal stabilization and transport, we perform: i) annual retraining sessions for all the operators in our Unit, ii) low and medium fidelity simulation sessions for nearby hospitals, iii) high fidelity sessions for colleagues working at geographically uncomfortable hospitals (i.e. island) and so needing for transport by helicopter, as a kind of “full scale CRM (Crisis Resources Management)”. In our opinion the traditional approach to teaching is inadequate for retraining of adult professionals. We propose simulation as the method to deepen knowledge, strengthen abilities and so optimize performances. Recording sessions and analysing them to discuss behaviours is a main instruments for debriefing. Every kind of support (e.g. e-learning platforms, papery stuff, pocket memory materials, etc) is admitted and should be creatively promoted.

Effective Method To Remove Metal Elements from Pharmaceutical Intermediates with Polychelated Resin Scavenger

A catalytic reaction is an important methodology for the production of pharmaceuticals from the viewpoint of green and sustainable chemistry. Since elemental impurity levels should be controlled within acceptable limits in API, the development of removal of element is also important as well. The technology for removal of elements was developed using cost-effective polychelated resin scavenger. The precious elements were removed efficiently by passing through the packed cartridge filled with appropriate scavenger. The feasibility of the scavenger was evaluated, and the application for actual manufacturing process is described. In contrast to another type of immobilized scavengers, polychelated resin scavenger provides an inexpensive method to scavenge several elements.

Impact Prevention and Management of Emergency Situation for Sustainable Development

Planet earth is the only planet in the universe that has the most precious element - life. Life, in all its forms, consisting of all living organisms, the land and the ocean takes the Earth from the shores of seas and oceans to the peaks of the highest mountains. All these form the natural heritage to be used by our generation without compromising future generations the opportunity to enjoy the same living conditions. The most intelligent species on Earth depends on the man. From the beginning of its existence, for survival and basic needs interfered with or without the knowledge of the nature, helping fast enough to destroy more wealth than created, causing global warming or climate weather situations extreme irreversible planet Earth that created negative influences on health and life in all its diversity, the environment, cultural and material values important. The scale and intensity, frequency and complexity of emergency event generated by initiating and developing global policies aimed at maintaining priority natural heritage and reduce the risks of them. In this context Romania joins global efforts for sustainable development of the planet Earth. and the Ministry of Interior through the Emergency Department and the General Inspectorate for Emergency Situations coordinate international and national prevention activities and emergency management, human resources, material, financial and other resources necessary to restore the normal state including first aid qualified emergency care.

Phase Relations, Precious Elements Distribution, and Activities in the Cu-Fe-Pb-As System Saturated with Carbon at 1473 K (1200 °C)

In order to develop a new pyrometallurgical process for the elimination of detrimental arsenic and the recovery of precious elements, such as, silver, gold, and platinum from arsenic-rich copper-lead scraps, the phase relations in the Cu-Fe-Pb-As system saturated with carbon and the distribution of precious elements between the condensed phases generated during the equilibrium at high temperature were investigated. The investigation was carried out by performing a series of laboratory scale experiments using an electrical furnace at 1473 K (1200 °C), followed by the quenching of molten samples taken on the final stage. The samples obtained from the experiments were analyzed using electron probe X-ray micro analysis, inductively couple plasma, and carbon infrared spectrometry techniques. The results were discussed on the basis of the activity coefficient of arsenic, interaction parameters of minor components, and distribution parameters for precious metals in the three equilibrated alloy phases of lead-rich, copper-rich, and iron-rich that coexists in the corresponding miscibility gap. The present results suggest that the recovery of valuable silver and gold into the copper-rich alloy and lead-rich alloy phases and the elimination of arsenic and iron into the iron-rich alloy phase might be feasible.

Recycling of Indium From CIGS Photovoltaic Cells: Potential of Combining Acid-Resistant Nanofiltration with Liquid–Liquid Extraction

Electronic consumer products such as smartphones, TV, computers, light-emitting diodes, and photovoltaic cells crucially depend on metals and metalloids. So-called "urban mining" considers them as secondary resources since they may contain precious elements at concentrations many times higher than their primary ores. Indium is of foremost interest being widely used, expensive, scarce and prone to supply risk. This study first investigated the capability of different nanofiltration membranes of extracting indium from copper-indium-gallium- selenide photovoltaic cell (CIGS) leachates under low pH conditions and low transmembrane pressure differences (<3 bar). Retentates were then subjected to a further selective liquid-liquid extraction (LLE). Even at very acidic pH indium was retained to >98% by nanofiltration, separating it from parts of the Ag, Sb, Se, and Zn present. LLE using di-(2-ethylhexyl)phosphoric acid (D2EHPA) extracted 97% of the indium from the retentates, separating it from all other elements except for Mo, Al, and Sn. Overall, 95% (2.4 g m(-2) CIGS) of the indium could be extracted to the D2EHPA phase. Simultaneously, by nanofiltration the consumption of D2EHPA was reduced by >60% due to the metal concentration in the reduced retentate volume. These results show clearly the potential for efficient scarce metal recovery from secondary resources. Furthermore, since nanofiltration was applicable at very low pH (≥ 0.6), it may be applied in hydrometallurgy typically using acidic conditions.

Comparative analysis in residential property price level and price dynamics in urban and rural areas of Hajdú-Bihar County

In modern market economies residential real estate prices, price shifts and their correlations with macroeconomic factors are surveyed quite frequently. However, in contrast with the wide scope of foreign examples, so far existing analyses in Hungary have ignored examining relation and extensity of macroeconomic indicators and failed to examine their effect on real estate pricing. The scope of this survey is to highlight these potential correlations and thus develop new aspects of analysis. Although the examination needs further extension both in time and space, the results of this survey may help to understand the importance of the responsible management of the most precious element of national wealth from the perspective of sustainable rural development.&#x0D; Based on my preliminary results, there exists a strong correlation between the number of inhabitants of a settlement and the average real estate prices. Nevertheless, the correlation seems to be significant only for cities. In the case of smaller settlements the correlation still exists but at a lower level. As opposed to the results of former publications and my own expectations, no direct link could be tackled between the amount of income tax paid by private individuals and real estate prices either in the cities or in the villages within the territory and time span examined in my analysis. Although this correlation is measurable on a macro-economic level, my micro-regional analyses revealed the complexity of asset pricing and price volatility. Continuing this survey, my goal is to identify the hidden factors influencing real estate prices, whose thorough mapping may promote conscious rural development.

Bismuth Doped TiO2 Functionalized Hetero-Junction Semiconductor Anode with an Enhanced Reactive Chlorine Generation for Use in Electrochemical Wastewater Treatment

An electrolysis cell with a high-salinity wastewater as electrolyte is capable of anodic transformation of recalcitrant pollutants. In particular, chloride in the wastewater, which provides the ionic strength, also mediates an indirect oxidation of organic or inorganic compounds by producing reactive chlorine species (RCS). To this end, one can imagine that an enhanced RCS generation can reduce the energy consumption and hydraulic retention time. Metal oxide anodes, the core of electrochemical wastewater treatment system, have been traditionally categorized depending on an existence of electrocatalytic activity for oxygen evolution reaction (OER). PbO2 are SnO2 are well known materials with relatively high current efficiency (selectivity) toward heterogeneous oxidation of pollutants or chloride by formation of surface-bound hydroxyl radical. However, a large kinetic barrier frequently observed for these fully-oxidized metal oxides require a large energy consumption to increase the reaction rate (current). On the other hand, Pt group metal oxides (IrO2 and RuO2) with low OER overpotentials brought about a prodigious progress in water splitting and chloro-alkali cell. Redox transition of electroactive materials readily quenches the surface hydroxyl radicals to form higher oxides, resulting in a greater current response but with lower current efficiency toward the oxidation of chloride. In this presentation, we report a hetero-junction semiconductor anode with an enhanced RCS generation. The outer surface of our novel anodes is functionalized with bismuth-doped TiO2 which provide the surface hydroxyl group, while underlying IrO2/Ta2O5 layer serves as an electron shuttle. The hetero-junction semiconductor anodes were prepared by sequential thermal decomposition method. H2IrCl6 and TaCl5 were utilized as precursors for the IrO2/Ta2O5 (Ir:Ta = 7:3) layer annealed at 525 ºC. Aqueous titanium-glycolate complex was prepared from either hydroxo-peroxo titanium or titanic acid, which was mixed with bismuth citrate solution with variable molar ratio of Ti to Bi (annealing at 425 ºC). Prepared electrodes were analyzed by SEM, XRD, FT-IR and XPS techniques. Electroanalytic experiments including cyclic voltammetry (CV) and Tafel analysis were performed to assess the OER onset-potential and current response under variable anodic potentials. The current efficiencies of reactive chlorine generation were estimated using DPD reagent under potentiostatic conditions (2~3 V versus NHE) in dilute chloride solutions (50 mM NaCl) with circum-neutral pH. In addition, the stability of the electrodes was assessed by an accelerated life test.The Bi-doped TiO2 in the form of transparent thin film showed negligible current generation without the underlying IrO2/Ta2O5. Comparing CV data of the hetero-junction anode with IrO2/Ta2O5 anode indicated that the over-coating of Bi-doped TiO2 increases the OER onset-potential by 100~200 mV depending on the molar ratio of Ti to Bi, which was in consistent with the potentiostatic current densities reduced by 15 ~ 50%. Nevertheless, the hetero-junction fabrication was always found to increase the current efficiency of RCS generation. The highest current efficiency was observed for the Ti:Bi ratio of 7:3, which approached virtually unity (100%). A series of material characterization and electro-analysis suggested that the hydration of TiO2 provides active sites for the hydroxyl radical formation, while partial substitution with Bi resulted in a distortion in the crystalline structure and an increase in surface area. Consequently, the potentiostatic generation rate of reactive chlorine for Bi0.3Ti0.7Ox anode was almost twice of that for IrO2/Ta2O5. The accelerated life test predicted the lifetime of the hetero-junction anodes to be more than 2 year under normal operational range (300 A m-2), thereafter a dissolution of Ir was observed. Therefore, our hetero-junction fabrication can also elongate the service life without a loss of precious element.

Landscaped Estimation of the Ancient Mercuriferous Career Potentialities in the Algerian Northeast for Its Bio-Restoration

The bio-restoration project of the mercurial career of Guenicha operating in the region of Azzaba must not only take into account the potential of the site but also its integration into the surrounding landscape. To achieve this result we performed a qualitative estimation of the potentialities of the site to understand better the structuring of the space and these various affectations. We took into account the current occupation of grounds to locate the precious elements, the curiosities susceptible to remain constant in the landscape and to highlight sectors or zones of an exceptional fragility which we call sensitive sectors or zone where any intervention can influence the visual atmosphere of the landscape. The zoning allowed us to reveal two landscaped bulks represented by the plain of Azzaba and the career of Guenicha. At first time we identified their components. To increase the visibility of the site, we shall create the dominances which characterize them and we arrange the transitions between them. In the last we will link the study area with the surrounding landscape by offering the most sensible choice of a pardon to restore the soil and also achieve the integration with the surrounding landscape.

Progress in Platinum Group Element (PGE) in Black Shale Series

The black shale enriched in various precious metal elements and platinum group elements. And the PGE deposit in black shale series is a new promising mineral resource. Comprehensive research on the geology, geochemistry, petrology, mineralogy, fluid inclusion and geochronology of the PGE in black shale series has been carried out and made a series of achievements. This paper summarized the advances in PGE in black shale series and pointed out the controversial views about the source of the PGE.

Romantic Reinventions in D. H. Lawrence's "Women in Love"

Previous articleNext article No AccessRomantic Reinventions in D. H. Lawrence's "Women in Love"Eugene StelzigEugene Stelzig Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Wordsworth Circle Volume 44, Number 2-3Spring-Summer 2013 Article DOIhttps://doi.org/10.1086/TWC24044228 Views: 36Total views on this site © 2013 by The University of Chicago. All rights reserved.PDF download Crossref reports no articles citing this article.

Correlation among measures of stress, indicators of biohumoral nature and medico-legal considerations

Man devotes most of the daily time to work, and also a large part of physical and mental resources. Depression and many other morbid conditions can be related etiopathologically to the performance of a dangerous occupation in terms of quality (hazardous work activities, lack of motivation for deficient career opportunities) or merely quantitative (duration of work shifts, frequency shifts work). The medical legal ascertainment is limited because stress cannot be valued by objective nature, but only through precious elements collected directly by workers by questionnaires. This is in response to legal requirements in terms of civil liability, occupational disease and disability. The objective of this study is to analyze the change of cytokines (IL-6, IL-12, TNF-α) and stress-related hormones (prolactin and cortisol) in a sample of 314 individuals working at the University Hospital Umberto I in Rome without acute diseases but only with the "feeling stressed" for at least a month and to analyze if there is a correlation between some of these biochemical variables and stress values measured by questionnaire. The results of this study confirm the usefulness to associate laboratory analysis, such as the study of inflammatory cytokines and the hormonal profile, to psychometric tests, precious for the lower cost and in some cases also for the high diagnostic sensitivity, to reach a probative value which satisfies even the most demanding application of accuracy.

Simple organic molecules as catalysts for enantioselective synthesis of amines and alcohols

The discovery of new catalysts that can generate complex organic compounds via enantioselective transformations is central to advances in the life sciences;i for this reason, many chemists try to discover catalysts that can be used to produce chiral molecules with a strong preference for one mirror image isomer.ii The ideal catalyst should be devoid of precious elementsiii and should bring reactions to completion in a few hours using operationally simple procedures. In this manuscript, we introduce a set of small organic molecules that can catalyze reactions of unsaturated organoboron reagents with imines and carbonyls; the products of the reactions are enantiomerically pure amines and alcohols, which can be used to synthesize more complex, biologically active molecules. A distinguishing feature of this new catalyst class is the presence of a 'key' proton embedded within their structure. The catalyst is derived from the abundant amino acid valine and was prepared in large quantities in four steps using inexpensive reagents. Reactions are scalable, do not demand stringent conditions, and can be performed with as little as 0.25 mol % catalyst in less than six hours at room temperature to generate products in >85% yield and ≥97:3 enantiomeric ratio. The efficiency, selectivity and operational simplicity of the transformations and the range of boron-based reagents render this advance vital to future progress in chemistry, biology and medicine.