Weld repair practices without post weld heat treatment for ferritic alloys and their consequences on residual stresses: A review

The use of the half-bead, temper bead welding (TBW), and cold repair techniques is proving to reduce the cost of repairs and extend the life of aged components in power plants, petrochemical and hydrocarbon processing industries. It has been a significant area of interest for more than twenty years. A critical factor in this context is residual stress. The presence of residual stresses can lead to cracking which ultimately results in structural failure. This paper reviews the half-bead, TBW, and cold repair technique practices and their consequences on residual stresses within the nuclear, power, refinery and petrochemical industries and some of the contributions made by our group of researchers in this area.     

Evaluation of engineering properties of scoria in central Harrat Rahat, Saudi Arabia

 Although black scoria deposits occur extensively in western Saudi Arabia, there has been little work undertaken on its engineering characteristics as a light-weight aggregate which can be used in concrete for structural, masonry and insulating purposes. In an attempt to remedy this, central Harrat Rahat was selected for an engineering evaluation of scoria deposits in the vicinity of major cities where it may provide an easily accessible resource for natural aggregate. The petrography of the scoria and the deleterious material content were found to be acceptable by ASTM standards, but grading analyses indicated it would need to be processed before use. The other physical properties of the scoria such as bulk density, specific gravity and absorption indicated that samples from Jabal Halat Ash Shaykh quarry gave acceptable results. The porosity of the scoria is relatively high and some of the pore spaces are not interconnected. The material is pozzolanically active and can be also used as an additive to Portland cement. Received: 16 April 1999 · Accepted: 25 March 2000     

Hydrochemical Processes and Environmental Isotopic Study of Groundwater in Kuwait

Abstract

The present paper studies the hydrochemical processes and the isotopic characteristics of the main aquifers, the Kuwait Group and Dammam aquifers in the State of Kuwait. The water chemical types are dominantly NaCl and Na₂SO₄ in the Kuwait Group aquifer and Na₂SO₄, CaSO₄, and NaCl in the Dammam Limestone aquifer. The groundwater of the Kuwait Group aquifer is supersaturated with respect to quartz and calcite, and near saturation with respect to aragonite, but under-saturated with respect to anhydrite, dolomite, gypsum, and halite. While the groundwater of the Dammam aquifer is strongly under-saturated with respect to anhydrite, halite, and gypsum and is supersaturated with respect to quartz, dolomite, aragonite, and calcite. The saturation indices of the calcite and dolomite are increased in the direction of flow from southwest toward north-northeast. Al-Rawdhatain and Umm Al-Aish groundwater samples lie near the meteoric water line. They represent the effect of recharge by rainfall during pluvial period. The brackish palaeo-groundwater of the Dammam aquifer has low values of δ¹⁸O (?4.5 per mil) and δD (?35 per mil), which reveal that these waters are related to the palaeo-water from the cool wet period in the eastern Arabia 11,000 to 60,000 years B.P. The investigated brackish groundwater samples showed that the deuterium excess values are much lower than that of the Mediterranean areas. This may suggest that the evaporation was a prevailing process before the infiltration to the aquifers.     

Stress-strain curve for the design of high-strength concrete elements

Although the great advances in concrete technology have led to the possibility of obtaining ready-mix concrete with compressive strength around 100 MPa, some national and international codes for concrete structures do not cover concrete strengths above 50 MPa. Many codes are under revision, but some of them (including the Brazilian Code) will still not include high strength concretes. Due to the different characteristics of higher strength concrete some design procedures traditionally used in normal strength concrete structures have to be changed. Different types of stress-train relationships for concrete have been proposed for the non-linear analysis of member behavior and for the ultimate state analysis of high strength concrete elements under combined flexure and axial load. In this work comparisons are made between proposed stress-strain curves and between the axial load-moment interaction diagrams based on these curves. Comparisons of test results with these diagrams, for columns subjected to eccentric compression, give an idea of the different degrees of safety obtained using those curves.

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Résumé Malgré les grands progrès de la technologie en matière de béton, qui ont rendu possible l'obtention de bétons résistant à une compression d'environ 100MPa, quelques codes nationaux et internationaux relatifs aux constructions en béton ne couvrent pas des résistance du béton supérieures à 50 MPa. Plusieurs codes sont en cours de révision, mais beaucoup (dont le code brésilien) ne s'intéressent toujours pas aux bétons à haute résistance. En raison des différentes caractéristiques des bétons à haute résistance, certains procédés de définition traditionnellement utilisés pour les constructions en béton normal doivent être modifiés. Différents types de relations contraintes—déformations ont été proposés pour le béton dans le cadre de l'analyse non-linéaire de son comportement et dans celui de l'analyse finale des éléments en béton armé en flexion combinée avec une charge axiale. Cet article compare les courbes contraintes—déformations proposées et les diagrammes interaction charge axiale—moment qui résultent de ces courbes. Les comparaisons effectuées entre les résultats expérimentaux et ces diagrammes, pour des colonnes soumises à des compressions excentriques viennent illuster les différents degrés de sécurité obtenus grace à ces courbes.

     

Effect of isomerization on the stability of the surface aggregation structure of chlorinated polyacrylamide thin films on the basis of interferometric observations

Three isomers of chlorinated polyacrylamides were synthesized by a solution polymerization technique. The prepared polymers were dissolved in acetone to prepare 0.1 and 0.05 wt % solution concentrations. Polymer thin films were then prepared by spin‐casting from acetone solutions onto a glass substrate. The prepared films were characterized by Fourier transform infrared (FTIR) spectroscopy and annealed at 80°C for 6 h. The surface morphology of the prepared films was studied before and after annealing with an interference microscope to determine the effect of isomerization on the stability of the polymer thin films. The thin film of the polymer with a chlorine atom in the para‐position showed better stability due to the ionic interaction with the glass substrate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2601–2606, 2002     

Evaluation of the quality of bread,biscuit and butcher's sausage supplemented with rootlets of malt sprouts

The dietary fiber components of the rootlets of malt sprouts were determined. The rootlets were incorporated at different substitution levels in two types of bread (flattened and pan bread), biscuits and butcher's sausage. The proximate analysis of these products were also determined. Substitution levels of 5% and 10% gave good and acceptable bread of higher contents of protein and fiber. Although biscuits containing up to 15% rootlets were acceptable, yet their sensory qualities were adversely affected. Butcher's sausage containing up to 10% rootlets were of good sensory and cooking properties. Meat substitution with rootlets improved the cooking quality, reduced the cooking losses and lowered the cost of production of butcher's sausage.     

Mass-transfer to a channel wall downstream of a cylinder

The electrochemical method is used to measure the mass-transfer to a channel wall downstream of a cylinder. For Reynolds numbers based on cylinder diameter Re > 50, the flow is unsteady, and the mass-transfer rate is a function of time. When 50 < Re < 200, the mass-transfer rate is periodic with a frequency in the range of 1–3 Hz. When the ratio of cylinder diameter d to channel height h is 0.25, the Strouhal number is measured to be 0.27±0.02, and when d/h = 0.51, the Strouhal number is 0.49±0.01. The average mass-transfer rate at various positions downstream of the cylinder is reported. Experiments are compared to two-dimensional numerical simulations. The simulated and experimental variations of Nusselt number with position and Re contain similar features, but exact agreement is not found.     

Extractability and functional properties of some legume proteins isolated by three different methods

The extraction of protein from the flour of three grain legumes (faba beans, chick peas and fenugreek) was investigated using three different methods. Three protein preparations were made: by alkaline extraction and precipitation at isoelectric pH (protein isoelectric precipitate, PIP); extraction with 0.5 M sodium chloride solution and precipitation by ionic strength reduction (protein micellar mass, PMM); extraction in aqueous or saline solution in the presence of pepsin or pancreatin (partially hydrolysed protein preparation, PHP). Two of the protein isolates had higher values of water absorption and fat absorption compared to their corresponding parent flours, with fenugreek being the exception. Oil emulsification of the isolates was in the descending order: PMM, PHP and PIP. The PHP isolate had the highest nitrogen solubility index (NSI) values at pH 2.4 followed by PMM at pH 5.7–6.4 and finally PIP at pH 4.5–5.5.     

Upper Cretaceous Duwi Formation shale’s oil potentiality Safaga-Quseir,Red Sea,Egypt

Duwi Formation shale deposits at Safaga – Quseir area were assessed by rock eval pyrolysis for its shale oil potentiality. The studied shale’s organic matter are mainly of type I, type II, mixed type I/II in addition to some of type III. The studied shale is described as very good source rock with total organic carbon (TOC?>?2?wt%). The kerogen maturation in the studied samples is immature according to PI and Tmax. Extracted shale oil from the studied samples as bitumen was fractionated by liquid chromatography (LG) into saturated hydrocarbon, aromatic hydrocarbon, resin and asphaltene. The saturated hydrocarbon was described by gas chromatography (GC), the pristane/phytane, isoprenoids/n-alkane and CPI ratios show that, samples were deposited in marine environment with some input of terrestrial environment and are characterized by immature level.The X-Ray Diffraction (XRD) analysis for the studied shale samples show their bulk minerals are mainly quartz, calcite, dolomite, gypsum, hematite and pyrite in addition to apatite and fluorapatite. While their clay minerals are mainly smectite and kaolinite. The chemical composition of the studied samples showed high concentration of trace elements such as Co, Cr, Cu, Ni, V and Zn which in turn through more lights on the depositional environment of the organic matter.