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By Jitka Jandová

In this study, hydrometallurgical processing of waste ZnO flue dust arising during zinc removal from galvanized low-alloy steel sheets was investigated on a laboratory-scale to obtain electrolytic zinc. The flue dust was separated from flue gases, generated during heating waste galvanized steel sheets in an electric furnace under air atmosphere at temperatures of about 1000oC. The dust, comprising tetragonal ZnO and insignificant amounts of SiO2, was contaminated by Fe, Mn, Pb, Al, Mg, Pb, Cu and Ca. The dust was leached in 0.5 and 1.0M H2SO4 and/or in 20 and 30% NaOH at different temperatures and different liquid-to-solid ratios to determine the optimum conditions leading to the highest possible selectivity of leaching and efficiency of Zn extraction in minimum time. The subsequent electrowinning process was performed with refined zinc sulphate leach liquors and/or with untreated zinc caustic solutions. Zinc sulphate leach liquors were purified using a combination of a hydrolytic pH-controlled precipitation, cementation and carbon refining. Effects of operational variables on Zn electrowinning have been studied for both sulphate and caustic electrolytes. The conventional plate-plate electrowinning cell has been explored in this study. Comparison of results obtained for both zinc electrowinning from acid sulphate and alkaline solutions is presented contribution.

Jan 1, 2003

By A. V. Tarasov

In order to improve technical, economic and environmental performance of hydrometallurgical processing of intermediate products containing copper and nickel, the Gintsvetmet Institute and the IMET Institute of the Russian Academy of Sciences have conducted studies into the efficiency of the use of alternating current of industrial frequency on processes applied for hydrochemical leaching of various copper- and nickel-containing materials. It has been found that: 1.Imposition of alternating current over the process of leaching of softly reduced nickel oxide with recycled copper sulfate solutions resulted in an increase by 20 to 30% of the rate of the copper cementation process and reduced by 20% its activation energy. At the same time, the recoveries of nickel, cobalt and iron to the leach solution increased up to 82.2%, 78.5% and 57.1%, respectively, and that of copper to the cement precipitate up to 74%. Optimal process conditions have been identified with respect to the current density, electrode material, copper concentration in solutions and the process temperature. 2.In the process of hydroelectrochemical sulfuric acid leaching of nickel and copper sulfides, the grain size, the phase form of sulfides, the solution composition (H2SO4, Cl?, Cu2+, Fe3+)and the current amperage had an effect on the nickel recovery to the solution, which reached 90%, while the degree of copper transfer to solution did not exceed 20%. The process of hydroelectrochemical sulfuric acid leaching of nickel and copper sulfides with an addition of Cl? made it possible to selectively recover nickel into the leach solution along with concentrating copper in the leach residue. 3.When subjecting samples of commercial-grade magnetic fractions of converter matte to sulfuric acid leaching, the imposition of electric current, the concentrations of sulfuric acid and chloride ion in the solution and the duration of the reaction process had an effect on the process. The nickel recovery was 85% and that of cobalt and iron was 95% and the recoveries reached 97.5%, 98.3% and 99.8% as a result of repeated treatment of the primary residue under similar process conditions. Up to 75% of copper, 75% of sulfur and 99.0-99.5% of palladium was concentrated in the solid reach residues. The experimental data obtained indicates that the use of AC for hydroelectrochemical sulfuric acid leaching for separation of copper- and nickel-containing intermediate products has favorable prospects.

Jan 1, 2003

By Fatbardha Osmani, Skender Osmani

"A system analysis of the resource and environment management (water, energy etc) starts from its definition. Unfortunately, there is not a unique semantics of the mentioned concept. On these circumstances, in this paper the following issues are presented: 1.A short view on the existing concepts of management. 2.A new definition on the concept of management. It is considered as a complex and rational activity on human and natural resources ,environment etc, which starts from a analysis of infrastructure ,technology , etc, mission , alternatives , project etc. and ends to an optimal output. Basing on this definition, the management has two principal components: strategy and policy. The strategy is referred as a blue print program (the same definition as in Game Theory), which contains all the contingency alternatives. , while the policy is referred as a strategy applied into practice. The strategy is the first , while the policy is the second one. The best alternative of a policy is the project, Each strategy has one and only one project. The mentioned definition erases the differences between concept of policy and politics. Each strategy has its alternatives ,the next has its sub strategy and so on, i.e. whatever are going to be the strategy, there are a hierarchy composed by sub strategies up to the simplest strategies applied by a single individual (human beings or robots). The strategy objectives are necessary and sufficient conditions for its realization i.e . the strategy is an optimal activity, in which all resources are integrated and processed . Several strategies could be joined into one( for example the surface water strategies of the Balkan countries) . In this view, the strategy could be globalized into optimal way basing on different criteria’s as social, economic, environmental, their risks and effectiveness etc. etc An example from the water management illustrates the mentioned concepts."

Jan 1, 2008

By Yang Tian-zu

Sodium pyroantimonate which is widely used as the clarifier in the glass industry and as the synergist in anti-flaming industry respectively has a production history of about 30 years in China. At present there is the production capacity of about 20,000 tons per year in China and China is chief producer of sodium pyroantimonate. In this work the production processes adopted by the producers of China, the operation conditions and the product qualities of sodium pyroantimonate prepared by different preparation methods have been summarized, and on the basis of comparing the advantages and disadvantages for each process the most advanced method - the air-oxidation method was introduced in detail. The production processes of sodium pyroantimonate mainly include the method of oxidation by sodium nitrate, the oxidation method of hydrogen peroxide, the potash salt method, the chlorination method and the air-oxidation method etc. The method of oxidation by sodium nitrate in which the crude antimony oxide, sodium carbonate and sodium nitrate are separately used as the raw material, the flux agent and the oxidant, has the advantage of short and simple technological process, but low grade quality of sodium pyroantimonate and bringing about serious environmental pollution are the disadvantages and this method has been substituted by other methods. Sodium pyroantimonate can be directly prepared by the hydrogen peroxide oxidation method with the advantages of simple technological process, high grade quality of the product and little environmental pollution. High grade quality of sodium pyroantimonate can be also synthesized by the potash salt method, in which industrial antimony white, the hydrogen peroxide, potassium hydroxide and sodium hydroxide are applied as the starting material. The disadvantages of these two preparation methods are high production cost and high requirements on the raw materials. The chlorination method with the crude antimony oxide, hydrochloric acid and chlorine as the raw material has the advantages of low production cost and high grade quality of the product. However complex process, high requirement of anti-corrosion for the equipments and producing plenty of waste water limit its application. The air-oxidation method with stibnite/jamesonite concentrate, sodium sulfide, and sodium hydroxide as the raw material and atmosphere as the oxidant is a newly developed method and its advantages are low production cost and the complex raw material can be treated by this method and its disadvantage is that the quality of sodium pyroantimonate is lower than that prepared by the oxidation method of hydrogen peroxide and the potash salt method.

Jan 1, 2006

By Yinlun Huang, Cristina Piluso

"Industrial sustainability looks to improve material and energy efficiencies, product quality and variety, and productivity within an industrial zone, thus pursuing the long-term sustainable development of the region. This paper introduces a systems-based modeling methodology, which provides industrial leaders with the ability to evaluate future production options to determine the path with the highest positive impact on both their own sustainability and the sustainability of the overall industrial zone. A comprehensive study on sustainable development of an auto-manufacturing focused industrial zone under uncertainty is illustrated. Introduction Sustainable development refers to a continuous process of improvements that must be followed in order to achieve a state of sustainability. In its most general form, a widely accepted definition of sustainable development was identified in the Brundtland Report as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs” [1]. Sustainability will occur when the material and social conditions can be maintained or improved for human health and the environment over time without exceeding the ecological capabilities that support them [2]. An industrial zone is defined as a geographic area comprised of a network of industrial sectors, each composed of a number of entities. Such a zone is highly integrated and complex, and contains numerous uncertainties due to each industry’s extreme dependencies on its suppliers and customers throughout the product supply chain. In the context of an industrial zone, sustainable development refers to the continuous process of advancements in the zone, and the entities that comprise it, creating more value, wealth, and profits (economically viable dimension), providing environmentally benign products with less raw material consumption and waste generation (environmentally compatible dimension), and collaboration and a direct relationship among all involved in the supply chain, i.e. the corporations, employees, suppliers, investors, communities, customers, etc. (socially responsible dimension). These are the triple bottom lines of industrial sustainability. In order for economic, environmental, and social sustainability improvements to be successfully implemented within an industrial zone, the industrial decision makers must possess system-wide analysis abilities. The analysis of the sustainable development of an industrial zone involves decisions at the local, regional, or national levels, which are complex and involves handling of ill-defined parameters with a high degree of uncertainty due to the imperfect understanding of the underlying issues [3]. This work focuses strictly on the uncertainties in future zone planning and a method and a scenario based approach that can be used to evaluate the sustainable development of an industrial zone among these uncertainties."

Jan 1, 2008

By Thomas Schuman, Jaan Kers, Lucas N. W. Damoah, Xiangjun Zuo, Lifeng Zhang

"Rapid technological innovation has propelled the use of electronic equipment leading to the generation of more and more waste electrical and electronic equipments (WEEE). Printed wiring board (PWB) is a component made of one or more layers of insulating material with electrical conductors. To investigate an environmentally friendly process to recycle PWBs, PWB samples with and without additives were pyrolyzed. Liquid, gas and solid products were achieved with different conversion fraction. Analysis of the exhaust gases from the experiments using GC-MS and MS showed that without CaCO3 additives poisonous gases such as C6H6 and HBr were produced which were adequately controlled if CaCO3 was added.IntroductionPyrolysis is one of the best methods for treating complex mixtures of waste polymers and to recover the material and energy content. The process consists of thermal decomposition at moderate temperatures in total absence or small amount of oxygen in which the structures of polymers break down into smaller intermediate products "". The decomposition temperature of a substance is the temperature at which the substance breaks up into smaller substances or into its constituent atoms 2). Thermal treatment of PWBs were reported using DC Arc Plasma furnace 3), and fixed bed reactor 4). One drawback in dealing with thermal treatment of PWB scraps is the likely production of super-toxic halogenated dibenzodioxins and dibenzofurans from the bromine containing structures. Pyrolysis of organic materials contained in waste PWBs leads to the formation of gases, oils, and chars which can be used as chemical feedstock or fuels ""'. Dehalogenation of the pyrolysis product of electronic scraps is essential to make it commercially acceptable. It would be obviously the most advantageous solution as pyrolysis and dehalogenation are carried out simultaneously. Reported pyrolysis investigations are at experimental stage and have been carried out in vacuum, molten salt, fluidized bed, rotary kiln, entrained, stationary, and moving bed reactors 7). Comparing to the incineration and combustion of PWBs, the pyrolysis process has several characteristics: 8'"">) 1). Converting the organic solid substance into fuel gas, fuel oil and carbon-black as storage energy; 2) Emitting toxic substances such as sulfur, bromine and heavy metals in wastes; and 3) Keeping metals from being oxidized. Although many researches into the pyrolysis of PWB wastes have been reported, most of the works have been carried out using analytical pyrolysis techniques or very small batch reactors ""~'5). Also, most of the works for the pyrolysis of PWBs haves concentrated on the composition of the organic products, particularly the brominated organics. The current study is to investigate the pyrolysis of PWB powders in a small TG-DTA scale and a 50-gram tube furnace scale."

Jan 1, 2011

By Carla Lupi, Mauro Pasquali

"Photographic technology is based on light sensitivity of silver halides that, because of silver properties, are capable of forming photographic images. Photographic laboratories and hospital departments because of digital photographic systems less use this technology today. Nevertheless recovery of silver is still advantageous because environmental problems related to Ag ions danger to biological system. Many processes have been studied to treat silver containing photographic bath: cementation, chemical precipitation and electrowinning. In this work, after preliminary voltammetric tests, a batch electrometallurgical process has been studied to completely deplete the silver containing photographic fixing baths. The effect, of silver concentration in the electrolyte, varying over the range 0,2-1 g/L, bath stirring and current density ranging from 10 to 500 A/m2 on process yield and deposit quality, has been investigated. Introduction Photographic wastes, electronic scrap and spent catalysts constitute the main sources of materials for silver recycling. Among those silver secondary sources, the photographic discharged material could be still important and useful, even if photographic laboratories and hospital departments, because of digital photographic systems, less use photographic technology. Several processes have been developped in order to recover silver used in the field of photography from both photographic solutions and scrap film paper[1-5]. Fixing solutions are very complex baths but, because of silver position in the electromotive series, electrolysis could represent an advantageous method for silver recovery. Electrolysis produces high purity silver without generating new pollutants, while the fixer can be reused: obviously it is necessary to purge off a portion of this solution in order to avoid the excessive build up of other deleterious compounds into solution. A tested recovery method was constituted by the dissolution of silver from X-ray films with concentrated nitric acid. Internal electrolysis and external electrolysis methods were carried out using a steel electrode as cathode and a copper electrode as anode [6]. Silver recovery from photographic chemical solutions has been also performed in a special cell [7]: the solution is supplied to the bottom of a non-agitated cell having a vertically elongated form and including a central anode enclosed by a cathode. An other study discloses the use of an electrolytic cell comprising at least one anodic compartment and one cathodic compartment: the solution is treated in the cathodic compartment and then recycled in the anodic one [8]. A more recent work proposes the use of zirconium cathode for the recovery of silver from photographic fixing solution [9]: studies carried out by cyclic voltammetry showed that about 98% of total Ag can be recovered with an electrical efficiency close to 92%."

Jan 1, 2008

By K. Twite, K. Mujinga, J-M. Dereydt, P. Louis

"GECAMINES is a large mining concern and the world's leading cobalt producer having some of the richest cobalt deposits in the world. Cobalt is associated in the ore with copper as sulphides and oxides and in some locations with nickel too. Specific hydrometallurgical processes have been developed by GECAMINES which had done an important contribution to the development of the cobalt hydrometallurgy.In the Shituru plant, cobalt is obtained from an unique in-pulp electrolysis process, while in Lullu, cobalt is electrolyzed in a clear acidic solution giving a purer deposit. In the beginning of 1996 Shituru started the treatment of mixed Cu-Co-Ni Shinkolobwe hydrates obtained as by-product of an uranium solvent extraction plant. A typical analysis of this feedstock is: 2% Cu, 8% Co and 4% Ni.The nickel sulfide depolarized cementation process developed previously by GECAMINES was inefficient to treat such a high level of nickel contamination and it was decided to produce alloyed Cobalt-Nickel cathodes in the Shituru tankhouse.As anticipated from laboratory tests as previous studies and publications, a lower Ni/Co in the deposit was obtained compared to the Ni/Co ratio solution, despite the nickel reversible electrochemical potential is somewhat higher than the one of cobalt (-0.25 V vs -0.28 V).In this paper, the process flow-sheet and production data are given. Cobalt alloy with 5 - 20 % Ni was obtained at a production level of 300 t per month. The process developed is a new contribution to cobalt hydrometallurgy."

Jan 1, 1997

By M. Cross, K. Pericleous, A. Mouchmov

"Copper - nickel - sulphide alloys are typically cooled and solidified in 4, 8 and 16 tonne ingots. These ingots exhibit a variation of grain size distribution and macro segregation of the prime alloy components throughout. The former is assumed to be primarily due to the dominant relation between grain growth rate and the cooling profile, whilst the latter is heavily influenced by buoyancy driven residual convection. The objective of this research program is to examine the extent to which it is possible to develop a 'broad brush' computational model of this ingot cooling process, that can predict some 'integral' measure of the grain size (e.g. average diameter) and the macro-segregation as a function of operating conditions.A computational modeling software framework, PHYSICA+ is used to simulate the complex process of ingot casting, which involves coupling between different physical phenomena. The entire model involves:(i) a 'broad brush' grain growth model that could be used in the prediction of micro/macro-structure of alloy ingot cooling processes,(ii) a heat transfer and solidification model which takes into account a second phase transformation of P NhS2 to heazlewoodite, and (iii) NS fluid flow simulation which provides a good basis for further micro/macro segregation modeling.At this stage some results of the 3D convection driven thermal cooling and solidification profiles will be shown, together with the 'integral' model for the grain size prediction."

Jan 1, 2001

By Alexander V. Derevyanko, Victor P. Popov, Alexander I. Raitchenko

"If an electric current flows along some electroconductive suspension in columnar form the solid particles are 'experienced thermal, mechanical, and electromagnetic influences.The objects were suspension Sn (liquid) - Ni-Cr-Mo-W alloy (solid particles). This is refractory alloy on the Ni base. The direct constant current (with density -106 A/m2 ) flowed through the named suspension during 180+300 sec. At the beginning of experiments samples were ones containing particles suspended uniformly in volume. Although density of solid particles was ~9x103 kg/m3 , i. e. higher than density of liquid Sn (-6.8x103 kg/m3 ), after end of this processing, the non-uniform distribution of particles in volume of samples was observed: concentration of Ni-alloy particles in lower part was smaller than their concentration in upper part of samples, and simultaneously their concentration is increased near outer surface. There was probably the natural convection of Benard-Rayleigh type which had carried, so lid particles upwards, and, in same time, there was the action of spatial Lorentz-forces directed to center forcing the radial movement.The knowledge of named phenomena can be useful for elaboration of technology of gradient dispersed materials and development of some materials science fields.IntroductionThe liquid metal with the electric current or under the alternating magnetic field is experienced compression. This action causes the pressure within metal and the change of the surface of the metal column (see, for example, [1-4]). One of results of such an electromagnetic compression is extraction of the foreign solid particles from a cylindrical liquid sample to surface in the radial directions. However, more complicated paths of the inclusions are observed under some conditions of electric treatment."

Jan 1, 1999

By Kazuyoshi Sato, Keizo Uematsu, Nozomu Uchida

"Confocal fluorescence scanning laser microscope was applied to characterize the surface flaw of ceramics in great detail. A high potential -of the characterization technique is presented first. Then the technique was applied to clarify the relationship between the flexural strength of ceramics and the surface flaw. This kind of direct information of surface flaw should be essential for the fundamental study in this area, but has been lacking. The examination revealed that large defects are present on the machined surface of ceramics. Their size is consistent to the flexural strength measured on the material. The characterization tool was also applied to examine the formation of surface flaw in machining of ceramics.IntroductionClarification of fracture origin should be the starting point in the study on strength in ceramics. However, this task has been extremely difficult in some ceramics, such as an alumina ceramics. It may break from both internal and surface flaws. The former should reflect the quality of production process and the latter the machining. Examination of surface flaws should be very important for developing a better machining method for ceramics. The knowledge may valuable for establishing a better production process also.ExperimentAlumina Referceram (JFCC) was used as samples. They are cut to size of 3x4x40mm, and the surfaces were ground to meet the requirements of testing method for flexural strength of fine ceramics, JIS R 1601. They were soaked in an aqueous solution of fluorescence dye and evacuated with an aspirator for an hour to allow the solution penetrate into surface flaws. After excessive solution remained on the surface was removed by gentle washing, the specimens were dried at 120°C for 48 hours. The 4 point bending mode was applied to measure the fracture strength."

Jan 1, 2000

By Matsufumi Takaya, Yukihiro Sakamoto

"Electric field emission properties from CVD diamond fabricated using pulse-modulated microwave plasma CVD were studied. Diamond was synthesized by microwave plasma CVD apparatus equipped with a pulse-modulated microwave power supply. Pulse conditions were varied from 1 to 10 seconds for pulse periods and from 0.1 to lHz for pulse frequency either. Surface morphologies of the deposits were differed by pulse frequency and duty cycle. As a result, FE properties prepared by different pulse duty cycle were different from continuous film which synthesized using continuous microwave significantly. Highest current density was obtained from the uneven morphology diamond film prepared at 17.5% pulse duty cycle.FE properties of the CVD diamond were depended on surface morphologies that related to the pulse conditions.1. IntroductionDiamond has excellent physical and chemical properties as an industrial material. Especially, hydrogen terminated diamond had the negative electron affinity (NEA) 1) and CVD diamond has this NEA property either as deposited 2). So the electron emission source to the FED is expected as one of this application of CVD diamond as cold cathode of electric devices. We studied on FE properties of various CVD diamond, pulse microwave plasma CVD diamond showed better property than those of other CVD diamond 3).This report studied on· the effect of the duty-cycle of pulse modulate microwave condition on FE properties of the diamond fabricated by pulse modulated microwave plasma CVD."

Jan 1, 2000

By James D. Navratil

Although liquid membranes have several advantages over conventional liquid-liquid extraction, problems such as membrane instability remain. In order to solve these problems, we have combined an electrostatic field with the principle of liquid membranes and developed a novel reactor system for rare earth recovery. Our cylindrical reactor, filled with extractant and diluent, is divided by means of a perforated cylinder into an outer annular extraction cell and an inner stripping cell. Below the extraction and stripping cells are two settlers for the aqueous solutions. The design of the reactor permits the organic solution to flow freely through the special perforated cylinder and the added feed and strip solutions, outside and inside the perforation, respectively, to be completely separated.

Jan 1, 1990

By Munetaka Iwasaki

Nitrogen strongly affects mechanical properties of steel and therefore we may sometimes modify the various processes for its content. Numerous studies based on the results of chemical analysis of quenched samples were reported with a few exceptions of Hot Sievert method. The technique always poses a risk of uncertainty whether the true content of nitrogen in liquid metal is measured or not. In this study vacuum remelting under relatively low pressure was done to enhance gas phase mass transfer. Total pressure of the melt chamber was about 10-3 pa and electron beam heating was used. Mass spectroscopy was used for the direct observation of the rate of denitrization. Nitrogen molecules or atoms were detected by a mass spectrometer set above the melt. Continuous monitoring of the intensity of the fixed mass number may reflect the transfer of nitrogen from the melt to the vacuum. The results of the new and conventional techniques agree, both technique can be verified.

Jan 1, 1999

By C. M. F. Viera

In this work the properties of a clayey ceramic incorporated, up to 10 wt.%, with three types of wastes from a water treatment plant was evaluated. To determine the physical and mechanical properties such as linear shrinkage, water absorption and diametrical compression, specimens were prepared by 18 MPa uniaxial pressure and then fired in laboratory furnace at 700oC. The results indicated that the wastes incorporation changed the properties of the clayey ceramic. From the results it was found it possible to recycle these wastes into clayey ceramic in low amounts to avoid deleterious effect on the quality of the fired product.

Jan 1, 2008

By John R. Hugens

Modifications in the ALSCAN method of measuring hydrogen dissolved in liquid aluminum have made it possible to monitor the level of hydrogen dissolved in liquid copper. Measurements from the tundish show a correlation with eddy current readings from the continuously cast and rolled copper rod from the continuous casting and rolling system at Amarillo. The measurements also indicate that the copper in the tundish is supersaturated with hydrogen.

Jan 1, 1994

By Fathi Habashi

The behavior of pyrite, covellite, and arsenopyrite during leaching is different from other sulfides due to the presence of the disulfide ion, Sl. Arsenopyrite contains in addition, the diarsenide ion, Asl. The disulfide ion undergoes auto-oxidation in high acidity leading to elemental sulfur and sulfide ion formation: The sulfide ion may oxidize further by oxygen to elemental sulfur if high acidity is maintained. In neutral medium, the disulfide ion does not undergo auto-oxidation but oxidizes to thiosulfate then to sulfate: This leads to the two overall reactions observed experimentally: In acid medium and in neutral medium Covellite and arsenopyrite behave similarly.

Jan 1, 1995

By Lifeng Zhang, Zineb Benouahmane, Yaqiong Li

Experimental oxidation tests at high temperature (1000-1200 °C) on SiC samples have been respectively performed under wet and dry air atmosphere for different holding times. The thickness of thermally grown oxide was experimentally measured by DEKTAK Stylus Profilometry. The results showed that the oxidation rate was increased with temperature and holding time, corresponding to a passive oxidation regime which led to the formation of SiO2 layer. The sessile drop method was employed in order to measure the contact angles between Si and SiC at high temperature. Contact angle can be varied from 39.6° to 75.6° by controlling the atmosphere. The deoxidation of the oxide layer and infiltration of liquid silicon caused a decrease in the contact angle.

Jan 1, 2016

By Carlos Maurício. F. Vieira, Lázaro A. Rohen, Sérgio N. Monteiro, Rafael G. de Castro, Gustavo X. Borges, Maycon A. Gomes, Frederico M. Margem, Anna C. C. Neves

Economic and environmental benefits are motivating studies on natural fibers, especially lignocellulosic extracted from plants, have been studied to substitute synthetic fibers, such as glass fiber as reinforcement in polymer matrices. By contrast to synthetic fibers, natural fibers have the disadvantage of being heterogeneous in their dimensions specially the diameter. About the hemp fiber, little is known of their dimensional characteristics. The aim of the present work was to statistically characterize the distribution of the diameter of hemp fibers. Based on this characterization, diameter intervals were set and the dependence of the tensile strength of theses fibers with a corresponding diameter was analyzed by the Weibull method. The diameter was measured with precision using a profile projector. Tensile tests were conducted on each fiber obtain mechanical strength. The results interpreted by Weibull statistical showed a correlation between the resistances of the fiber to its diameter.

Jan 1, 2015

By F. W. H. Dean

A very sensitive sensor for the detection and measurement of hydrogen in solid steel is described. This technique is non-invasive and uses a collector to sweep the hydrogen emanating from a steel surface and feed to it sensor. This method is particularly sensitive, resolving fluxes to < 2 pI cm?2 S?I, with a linear measurement up to 1000 pI cm&apos;2 S?I, The collector is held on the steel substrate by magnets and it is shown that emanation of hydrogen from the steel is controlled by bulk diffusion of the hydrogen through the steel. The technique is demonstrated to have an excellent response time and reproducibility.

Jan 1, 2001