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This book presents the properties of concrete as needed in concrete construction, including strength and durability. All concrete ingredients (cementing materials, water, aggregates, admixtures, and fibers) are reviewed for their optimal use in designing and proportioning concrete mixtures. Applicable ASTM, AASHTO, and ACI standards are referred to extensively. The use of concrete from design to batching, mixing, transporting, placing, consolidating, finishing, and curing is addressed.
The research topic 'parent material for soil formation' is at the interface between the disciplines of geology and soil science; interdisciplinary research will be of mutual benefit. In order to foster such research and knowledge transfer, this paper presents the development of a novel geochemical-physical classification system for subsolum geological substrates as a basis for both understanding soil formation and estimating and modelling soil properties. It is based on information from classical geological surveys and maps and additional specific field data and laboratory analysis of surficial geology and is applicable to solid bedrock and unconsolidated deposits. In summary, the units of the classification system consist of three evaluation levels encoded in entities describing their lithogenetic, geochemical, and physical characteristics. Beside the geochemical-physical characterisation, the classification approach also considers the layer structure of unconsolidated deposits. The basis for the classification is mineral component groups of the subsolum geological substrates, namely dolomite, calcite, and felsic, mafic, and clay minerals. The categorisation is implemented in three distinct triangular diagrams with a scope of application according to the proportion of carbonate. The practical application includes the processing and classification of geological reference samples and was applied to 321 analysed field samples of unconsoli-dated deposits. In order to describe and evaluate the influence on soil formation and soil properties, we examined the soil analysis data of 389 and field descriptions of 1664 legacy forest soil profiles in the Tyrolean Alps. With the compiled dataset we were able to cover 50 different classification units representing approximately 92% of the forested area of Tyrol. We were able to show clear differences in the chemical and physical soil properties between units. Beside the mineral components of the parent material, the different lithogenetic entities play an important role in soil formation and soil properties. This is explained by the preliminary fragmentation of rock through different transport processes and distances as advanced soil genesis is facilitated by the presence of finer grain size. Hence, parent material is a key factor in soil formation, determining soils physical and chemical properties. The valorisation of geological information for soil science bridges the gap between the disciplines and contributes added value to other research fields. Due to the openness of the proposed classification system for the further differentiation of lithogenetic, geochemical, and physical entities, it is transferable to the entire Alpine arc and other mountain regions.
Geopolymers are alternative materials to portland cement, obtained by alkaline activation of aluminosilicates. They exhibit excellent properties and a wide range of potential applications in the field of civil engineering. Several natural aluminosilicates and industrial by-products can be used for geopolymer synthesis, but a lot of starting materials have the disadvantage of poor reactivity and low strength development. This paper presents a comprehensive review of the main methods used to alter the reactivity of aluminosilicate materials for geopolymer synthesis, as reported recently in the literature. The methods consist of mechanical, thermal, physical separation and chemical activation, of which mechanical activation is the most commonly employed technique. The reactivity of the activated aluminosilicate materials is mainly related to the activation method and the treatment parameters. Chemical activation by alkaline fusion is a promising method allowing preparation of one-part geopolymer materials, an alternative class of geopolymeric binders. However, the resulting alkaline-fused geopolymer products are vulnerable to attack by excessive alkalis.
Potential use of Geopolymers as binders in concrete instead of ordinary Portland cement (OPC) has attracted worldwide attention in recent years, due to its advantages such as more environment friendly, better durability and acceptable mechanical properties. In this paper, it is shown that the large resources of aluminosilicate waste materials in developing countries present a great opportunity for their use to make geopolymer concretes towards building of local physical infrastructure. This paper reviewed research on characteristics and properties of geopolymer binders and concretes. The effects of different raw materials, various activators, mixture formation and curing are discussed.
Assess the granite & Marble industry in Egypt. from the first point of exploration to the end .
Sandstone is a popular type of natural stone and is made up of collective grains of quartz. India is one of the countries blessed with various types of sandstones with appealing colors. Demand for Indian sandstones has increased in the international market and they are being exported to many countries like United States, United Kingdom, and New Zealand. Since Indian sandstones possess impressive qualities to durability, strength, and resistance to abrasion, they are being used in roofing, paving, flooring, aesthetic pillars, and stone carving. Quartz sandstone is a type where the elemental framework of sandstone is dominated by quartz and may contain a small amount of clay in the form of muscovite. Since the clay content in a quartz sandstone is much lower, they can be used as an effective replacement for conventional coarse aggregates in the production of cement concrete. In this paper, quartz sandstones coarse aggregates have been utilized as a substitute of conventional coarse aggregates and its response to sulfuric acid has been studied. It can be concluded that concrete with quartz sandstone aggregates up to 40% replacement showed better resistance to sulfuric acid exposure.
In this study oxalic, citric, and glycolic acids were used in order to reduce Fe and Ti (colored impurities) from the slimes (-75 µm) feldspar samples using organic acids. The results showed that removal ratios of the colored impurities from the feldspar samples were 67.9% for Fe and 43.75% for Ti using oxalic acid and the agitated leaching (AL) method. The influence of main parameters (temperature, pulp density, leaching time, and acid concentration) were examined by using full the factorial design (2 4) ANOVA-Yates test technique. Next, the removal ratios of Fe% and Ti% in the tests were determined to be 80.44% and 45.39%, respectively. Additionally, the main parameters which were obtained from the best results of AL were optimized for the-500+75 µm feldspar sample. Finally, the microwave-assisted pressure leaching (MAPL) method was apply to determine the effect of pressure on leaching. The obtained results indicated that the optimum removal ratios obtained were 95.74% for Fe and 70.88% for Ti by using the MAPL tests with oxalic acid. Furthermore, the measured whiteness (L) values were observed to be over 90%. This is a suitable purification ratio for the ceramic and glass industry.
This paper presents findings from microanalytical investigation conducted on disintegrated concrete that had been used to construct a weir within a coal mine in South Africa. The concrete was in contact with polluted mine water, commonly referred to as acid mine drainage (AMD). Accordingly, the weir had been exposed to AMD decant which led to disintegration of concrete due to chemical attack. Investigations were conducted by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD). The field samples examined consisted of soft, broken concrete chunks and a whitish powdery substance that had crystallised and formed a surface coating on certain cracked locations on the deteriorated concrete. No evidence of pyrite oxidation was found in the investigation. The observed deterioration is discussed in relation to acid attack mechanism and its possible co-existence with external sulphate attack process.
Geopolymer cement, high-alkali (K-Ca)-Poly(sialate-siloxo) cement, results from an inorganic polycondensation reaction, a so-called geopolymerisation yielding three dimensional zeolitic frameworks. High-tech Geopolymer K-Poly(sialate-siloxo) binders, whether used pure, with fillers or reinforced, are already finding applications in all fields of industry. These applications are to be found in the automobile and aeronautic industries, non-ferrous foundries and metallurgy, civil engineering, plastics industries, etc. Geopolymer cement hardens rapidly at room temperature and provides compressive strengths in the range of 20 MPa, after only 4 hours at 20°C, when tested in accordance with the standards applied to hydraulic binder mortars. The final 28-day compres- sion strength is in the range of 70-100 MPa.The behaviour of geopolymeric cements is similar to that of zeolites and feldspathoids; they immobilize hazardous materials within the geopolymeric matrix, and act as a binder to convert semi-solid wastes into adhesive solids. Their unique properties which include high early strength, low shrinkage, freeze-thaw resistance, sulphate resistance and corrosion resistance, make them ideal for long term containment in surface disposal facilities. These high-alkali cements do not generate any Alkali-Aggregate-Reaction. Preliminary study involving 27Al and 29Si MASNMR spectroscopy and the proposed structural model, reveal that geopolymeric cements are the synthetic analogues of natural tecto-alumino-silicates.
This study was conducted to investigate certain characteristics of tuff and volcanic ash quarried from Mt. Elgon and Mt. Rwenzori in Uganda that may render the materials beneficial for use in industrial applications as pozzolans. Both tuff and volcanic ash materials were ground and blended with Portland cement at varied replacement levels and tested for several properties. It was found that incorporation of 20 to 25% volcanic ash gave the highest compressive strength and substantially reduced alkali-silica reactivity. The ash met ASTM requirements for ‘Class N’ pozzolans. This study suggests that the volcanic ash, when ground to 506 m2/kg Blaine fineness develops high qualities for potential use as a mineral admixture in cement and concrete. Conversely, the use of tuff was found to significantly increase alkali-silica reaction. This reiterates the possible harmful effects of some pozzolans to concrete if used without precaution, discretion or thorough understanding of their characteristics.
Five types of granites [Rosa Arronches (RA), Cinzento Arronches (CA), Rosa Santa Eulália (RE),
Cinzento Santa Eulália (CE) and SPI] from Portalegre (SE Portugal) have been extensively used as
ornamental building stones in Portugal, and also in other countries including Japan, USA, England, Qatar,
Denmark and The Netherlands. Fresh specimens of these granites were sampled from their quarries, and
exposed to six, fifteen-day cycles of immersion in acidic solutions of HCl, H2SO4 and HNO3. The visual
changes observed in the mineral surfaces and the mass loss percentages were monitored during the ninety
days of chemical attack. Usually, HCl caused the highest mass loss and visual changes in the rock
minerals, followed by H2SO4 and HNO3. The results showed that the reaction of each rock to the acidic
solutions is related not only to mineralogical composition, texture, physical properties but also to the
initial state of rock weathering. Therefore, contrary to the common belief that granites are resistant to
weathering by acid rain, the adoption of preventive measures when applying ornamental silicate rocks is
strongly advised. Such studies can be highly useful for the ornamental stone sector companies, since
improved product knowledge can boost their trade, as well as allowing competitive differentiation from
their counterparts while increasing client trust.
The Rietveld method was successfully used for the quantitative phase analysis of zeolitized rocks containing montmorillonite, a phase in which the atomic positions cannot be determined exactly. The freely distributed program FULLPROF was used in its profile-matching mode with Cukα X-ray data. This program permits carrying out quantitative analysis without using structural data for one of the phases. This method was applied to a set of reference mixtures of kaolinite and quartz, in order to show its effectiveness compared to normal refinement. The composition of these synthetic mixtures covered the range between 10 wt% and 90 wt% of both components. The absolute errors were lower than 5 wt%. Also, a set of artificial mixtures of quartz, clinoptilolite, and montmorillonite were quantified with the profile matching mode applied to montmorillonite. The absolute errors were lower than 6 wt%. Ten different measurements and refinements were carried out on one of these samples to obtain estimates of the true standard deviations of the concentrations. The average error values obtained are similar to the error reported by the FULLPROF program from a single refinement. The application of the method to two zeolitized tuffs of the Chubut Group, Patagonia, Argentina, with different percentages of clinoptilolite, quartz, feldspars, and clay minerals resulted in an absolute error of 3 wt% (compared to the results estimated by chemical and thermogravimetric analysis). For the zeolite phase (clinoptilolite), it was necessary to refine the occupation parameters of the exchangeable cations and the structural water molecules. The results indicate that quantitative analysis by the Rietveld method, using the FULLPROF program in the profile matching mode for one of the phases, may be used as a routine tool for the characterization of mineral samples that contain phases with disordered structures.
Dissolution rates of 39 rock-forming minerals were determined at 20 °C and 100 °C and different pH values, using experimental set-ups which achieve near-zero cation concentrations. Weathering rates in nature for rock above surface were estimated from data in this study and data in the literature. Extraction in a Soxhlet extractor with boiling 2.5 m acetic acid causes an acceleration of such estimated natural weathering rates by a factor of 0.25 10 3 to 7 10 4 for nearly all important rock-forming minerals, including the carbonates. The applicability of such a comparative test for rock resistance to chemical weathering was corroborated by testing 32 different rocks and building stones. Run times of only one to four days were needed for a reliable result.
In this study, mechanical activation of bauxite was done using ball milling to alter the material’s geopolymeric reactivity. Geopolymer mortar composites were then prepared by partially replacing the volcanic ash with 0 to 25 wt% activated bauxite. A mixture of sodium hydroxide and sodium silicate, was used as the alkaline activator. Workability, compressive strength, pore volume and water absorption characteristics of the geopolymer mortar composites, were determined. Microstructural investigations were carried out using X-ray diffraction, Fourier transform infrared spectroscopy, electron and optical microscopy. It was found that bauxite of higher fineness gave greater geopolymeric reactivity and promoted the formation of a compact microstructure containing fewer and smaller pores. Incorporation of 15 wt% bauxite of 1000 to 1730 m²/kg Blaine fineness, gave optimal mechanical and physical properties. The volcanic ash geopolymer mortar composites synthesized in this study, gave relatively high compressive strengths and generally low water absorption characteristics, indicating the binder’s potential for use in structural applications.
The objective of this study is to investigate how exposure of concrete to organic acids affects its resistance to mechanical abrasion and to identify the most important factors contributing to its abrasion resistance under acid exposure. The abrasion resistance of both cement pastes and concrete materials with different water-to-cement ratios (w/c), coarse aggregate type, and proportions of aggregate were experimentally measured after exposure to organic acids. In addition, the effect of silica fume, latex, fibers, and chemical surface hardeners on the abrasion resistance of cement paste and concrete materials were investigated. The results indicate that in the absence or presence of an organic acid attack, the abrasion resistance of concrete is primarily a function of the hardness of the coarse aggregates and w/c plays a secondary role. While a secondary factor, the effect of w/c on the abrasion resistance is more significant in the presence of an organic acid attack.
This paper presents the development of a new mix design method for fly ash geopolymer mortars activated using combined sodium silicate and sodium hydroxide solutions. For a specified value of compressive strength, specified value of workability, and known chemical properties of the sodium silicate solution to be used in a mixture, the proposed method generates mixture design parameters consisting of activator to fly ash ratio, sodium silicate to sodium hydroxide ratio, and molarity of sodium hydroxide. It was found that the actual compressive strengths and actual workability values obtained from tests were satisfactorily comparable to the designed values. The proposed method concept can be applied to generate relevant mix design charts for various types of geopolymer binders.
Batch and column experiments were performed to evaluate contaminant removal from acid mine drainage (AMD) using volcanic scoria zeolite (VS) with or without zero-valent iron (ZVI). Two sources of AMD were used, comprising WZ from a gold mine and TDB from a coal mine. Both the WZ and TDB were acidic mine water with pH values of 2.43 and 2.93, respectively. It was found that VS was effective in removing heavy metals from AMD despite attaining a relatively lower maximum pH of 5.5, compared to the pH values of 7.0–8.5 attained using ZVI. The reactive media VS, ZVI, and 50:50 ZVI-VS all achieved effective removal of Al, Fe, Zn metals. The mixture 50:50 ZVI-VS gave the best contaminant removal performance, relative to the other reactive media used in the investigation.
Hematite and Goethite minerals were formed in ZVI upon its exposure to AMD during the mine water treatment. The VS that was exposed to AMD showed enhancement of Diopside and Augite along with the formation of two new phases comprising Forsterite and Ferroan. Geochemical changes and microanalytical investigations altogether showed pH-dependent chemical precipitation to be the main mechanism of heavy metal removal by ZVI, while adsorption and cation exchange processes were found to be responsible for pollutant removal by VS.
This investigation involved a column study and model simulation to evaluate longevity of zero-valent ion (ZVI) and pervious concrete (PERVC) reactive barriers for treatment of acid mine drainage (AMD). Each of the reactive media were evaluated for sorption capacity and hydraulic performance under the dynamic flow conditions of a column setup. The test data obtained were applied to the one-dimensional advective-dispersion transport equation to predict geochemical changes in concentration of contaminants flowing through a reactive barrier, as a function of time and distance. PERVC was found to be more effective in contaminant removal from AMD than ZVI. PERVC raised the pH of AMD from 2.99 to an average value of 11, compared with a maximum pH of 9 attained by ZVI treatment. While both media achieved complete removal of the main contaminants comprising Al, Fe, and Zn, the PERVC containing 30% fly ash (30FA-PERVC) had greater retardation factors and higher overall removal efficiency than ZVI. The hydrodynamic dispersion coefficient for 30FA-PERVC was 0.4 to 4×10-4 m2/s compared with 0.2 to 5×10-6 m2/s for ZVI. A barrier wall of 1.5 m thickness was estimated to provide indicative treatment life spans of 5 and 10 years for ZVI and 30FA-PERVC reactive media, respectively. Based on these results, the longevity of 30FA-PERVC reactive barriers can be about twice that of ZVI barriers.
Dolomite is one of carbonate minerals that contain magnesium. Magnesium is important element used in many aspects of life such as cofactor of many enzymes in human body, nutrient for plants, and raw material in automotive industry. Dolomite can be processed through low temperature process to obtain magnesium and calcium oxide that is needed in important applications such as base material for making drugs, raw material in the synthesize slow release fertilizer, materials for fire retardant, component for catalyst, etc. One of the important step of this low temperature process is dissolution of dolomite. Optimizing the dissolution process determines the % extraction of magnesium and calcium oxide from dolomite. The dissolution of dolomite from Gresik, East Java Provence Indonesia, in chloric acid solution has been conducted. Chloric acid concentration and pulp density are the variables that were observed. The dissolution of magnesium and calcium from Gresik dolomite was found to be very fast. The stable stage of dissolution can be reached for 5-10 seconds. The % extraction is mainly determined by the molar ratio of chloric acid / dolomite. At molar ratio of chloric acid / dolomite equal or above stoichiometric of dolomite dissolution, % extraction of magnesium is almost 100 %.
This book summarizes the technical advances in recent decades and the various theories on rock excavation raised by scholars from different countries, including China and Russia. It not only focuses on rock blasting but also illustrates a number of non-blasting methods, such as mechanical excavation in detail. The book consists of 3 parts: Basic Knowledge, Surface Excavation and Underground Excavation. It presents a variety of technical methods and data from diverse sources in the book, making it a valuable theoretical and practical reference resource for engineers, researchers and postgraduates alike. © Metallurgical Industry Press and Springer Science+Business Media Singapore 2017.
The genesis of granite is intimately related to the dynamic structure of the Earth. Granite is the main component of continents; it is one of the oldest known rocks; and the geological history of granite provides the main evidence about the growth and evolution of continents through time. Granite formed in a number of different situations. Some granite was generated in zones of rifted continental or oceanic crust, but most granite was generated in zones of collision between continents and oceanic crust, and where continents were amalgamated. Granite formed by two different processes: by fractional crystallization of basaltic magma; and by melting older continental crust. Between these end members, there is a spectrum of hybrid processes, including mixing of basaltic and granitic magmas, and contamination of basaltic magma by partial melts of different kinds of continental crust. Although superficially simple and similar, most granites reflect a complicated history of multistage, hybrid processes. This complexity has led to a diversity of interpretations, and the origin of granite has been one of the most hotly debated topics in geology. The following review outlines the nature and diversity of granite; where, how, and when granite was generated; how it was intruded through the crust; the structures that it formed; and the history of debates over its origin.
Pervious concrete was investigated for potential use as a permeable reactive barrier (PRB) for treatment of acid mine drainage (AMD). Pervious concrete mixtures of various water/cement ratios (0.50, 0.40, 0.35, 0.30, 0.27) and cement contents (300, 360, 380, 400 kg/m(3)) were prepared. Dolomite and granite aggregate types, size 9.5 mm, were employed. The tests performed were density, compressive strength and porosity. Water treatment was determined by analysis of the influent and effluent AMD after passage through the pervious concrete. It was found that a filter thickness of at least 500 mm was required to increase the pH of acidic mine water from 2.8 to between 5 and 7, and achieve a corresponding reduction in electrical conductivity. When used in the filter mix design, the granite aggregate gave better treatment performance in comparison with the dolomite aggregate. The concrete PRB treatment led to the effective removal of major metals from the AMD. The treatment reduced the metals in the AMD by 30% sulfate, 99% iron, 50-83% manganese, 85% calcium and 30% total dissolved solids. There was, however, a noticeable increase in magnesium concentration in the water effluent 49-66%. These results are short-term tests and further work is in progress to investigate the system's life expectancy.
The evolution of hydraulic conductivity and porosity during the process of dedolomitization was examined in a series of laboratory experiments by analyzing the effects of concurrent dolomite dissolution and calcium carbonate precipitation. Linear flow experiments were performed in columns of crushed sucrosic dolomite by injecting different concentrations of HCl at various flow rates. Temporal changes in head gradient were used to calculate overall hydraulic conductivities of each column, while chemical analyses of the effluent acid enabled estimation of porosity changes during the experiments. After each experiment, the rock samples were retrieved and sectioned in order to study the pore space geometry, micromorphology, and mineral concentrations. A range of injected HCl concentrations and flow rates was identified which leads to oscillations in the effective hydraulic conductivity and porosity of the evolving rock samples; in all cases, however, the porous medium ultimately clogged. Short-term experiments were also used to study the formation of dissolution and precipitation bands along the columns. Under the experimental conditions, dolomite dissolution is a reaction rate controlled process; experiments indicated that, as such, the flow rate and the pH of the injected fluid affect dissolution only during the initial stages, when calcium carbonate is dissolved. On the other hand, both the flow rate and the pH of the injected fluid strongly influence the precipitation process throughout the duration of the experiments because higher flow rates retard nucleation. These findings are in qualitative accordance with field observations of dolomite formations.
Synopsis
The paper reports tests to determine the relative rates of erosion of siliceous-gravel and limestone-aggregate OPC concretes subjected to sulphuric acid concentrations of 0·0016% and 0.02% by weight. Care was taken to simulate conditions not too divorced from practice. The limestone-aggregate concrete eroded to present a relatively smooth surface with no detritus. In contrast, the siliceous-aggregate concrete eroded to form a very irregular surface with considerable aggregate detritus. The rates of erosion of the siliceous-aggregate concrete were very sensitive to the quality of the cement paste matrix, whereas the rates for the limestone-aggregate concrete were relatively insensitive. The behaviour of the limestone-aggregate concrete can be exploited in certain applications. There is no increasing surface roughness or accumulation of debris to reduce flow in channels, and damage with scrapers in sedimentation tanks can be minimized with a smoother surface. Design for erosion with limestone concretes entails estimating the thickness of a sacrificial layer of concrete appropriate for the rate of acid attack and the design life of the structure.
Quantitative determination of the mineralogical composition of hydrothermally altered rocks was performed by means of the Rietveld method using X-ray powder-diffraction data. Initially, experiments were carried out to minimize systematic errors arising from preferred orientation of particles as well as micro-absorption. The precision of the proposed method was tested by independent replicate sample-preparation and analyses. The closeness of the replicate phase-determinations showed that random within-laboratory errors were comparatively small. Expressed as chemical compositions, the quantitative results are in good agreement with the major oxide concentrations determined by X-ray fluorescence. The results indicate that the relative abundanc es of phases and refined element substitutions were accurately determined. The method developed was applied to hydrothermally altered rocks from the Waterloo volcanic-rock-hosted massive sulfide (VHMS) deposit in Queensland, Australia. Hierarchical cluster analysis led to the discrimination of several mineralogically distinct alteration-induced assemblages. These mineral assemblages are characteristic of specific zones of alteration. The strong spatial zoning with respect to the mineralized body and the distinct mineralogical assemblages of the alteration halo are interpreted to result primarily from varying degrees of hydro lytic decomposition and potassium metasomatism of the wallrocks. Based on these results, we suggest that quantitative phase-analysis by the proposed method represents a new powerful tool in studies of alteration halos.
At present, a computer model is being developed to predict the corrosion of concrete construction components subjected to acidic solutions with pH values ranging between 4.0 and 6.5, i.e. exposure classes XA3 down to XA1 according to DIN EN 206-1. The concrete may contain Portland cement based binders with dissolvable or acid resistant aggregate. Calcium aluminate cement is also considered. The concrete degradation is characterised by a corroded layer of high porosity whose thickness is determined by the combination of dissolution, precipitation and transport processes which depend on cement chemical composition, binder reactivity, aggregate reactivity, grading curve as well as concrete composition. It is also intended to include the effect of abrasion. The model components will be described in detail in forthcoming publications.
Dolomite-mineral planning factsheet
- D Highley
- A Bloodworth
- R Bate
- Highley D.
Introduction to mineralogy and petrology
- S K Haldar
- Haldar S. K.
Applied mineralogy: Applications in industry and environment
- S Mukherjee
- Mukherjee S.
The surface reactions of silicate minerals, part I-The reactions of feldspar surfaces with acidic solutions
- V E Nash
- C E Marshall
- Nash V. E.
Recovery of SiO2 and Al2O3 from coal fly ash
- G Sedres
Carbonate and gypsum, methods of soil analysis: Part 3 chemical methods
- R H Loeppert
- D L Suarez
- Loeppert R. H.
Geology, landform, minerals and rocks
- J Rafferty
- Rafferty J.