Surface and bulk properties of ancient Egyptian mortars. Part I: X-ray diffraction studies

A series of Ancient Egyptian Mortars were extracted from the great Giza Pyramid, the second Giza Pyramid and the Sphinx and its adjoining temple. X-Ray Diffraction studies revealed the presence of gypsum, calcite and silica in most of the samples with a clearcut predominance of gypsum in the samples extracted from the Sphinx. Calcium silicates of different crystallographic modifications seem to be present in a large proportion of the samples. X-Ray studies carried out on heat-treated samples indicated the prevalence of the hemihydrate or γ-CaSO₄ modification until a temperature as high as 400°C.     

The dissolution of cellulose in anhydrous chloral/aprotic solvents

Two new approaches toward the chemical modification and rapid dissolution of cellulose pulp in aprotic solvents containing chloral are presented. In the first method, cellulose pulp is water activated and then solvent exchanged prior to the addition of chloral. In the second method, cellulose pulp is heated in refluxing solvent and then cooled to ambient temperature before the addition of chloral. The methods do not entail the use of catalysts but require the preactivation of the pulp prior to treatment with chloral. Clear solutions obtained by the water activation–solvent exchange method were cast into films, and after washing with water the product was soluble in a variety of organic solvents including acetone. IR and NMR (¹H and ¹³C) analyses as well as chemical analyses led to the conclusion that a cellulose chloral hemiacetal with a DS of 2.2 is initially formed which then slowly decomposes upon standing at 23°C to a relatively stable hemiacetal of DS 0.4. Complete regeneration to cellulose results upon standing for an extended period or treatment with 1 N acetic acid at 80°C, 1 N HCl at 50°C, 0.5% NH₄OH or 0.1 N NaOH at 23°C. When solutions, obtained by the hot solvent activation method, were coagulated in water at ambient temperature, regenerated cellulose was obtained. In both methods, little or no degradation of the regenerated cellulose resulted.     

Effects of processing on oxidative stability of sesame oil extracted from intact and dehulled seeds

Oxidative stability of oils extracted from intact and dehulled sesame seeds was determined by monitoring changes in fatty acid composition, iodine value (IV), peroxide value (PV), conjugated diene (CD), para-anisidine value (p-AV), and 2-thiobarbituric acid (TBA) value and by nuclear magnetic resonance spectroscopy after storage under Schaal oven conditions at 65°C for up to 35 d. The oils from coated seeds were more stable, as reflected in PV, CD, p-AV and TBA values, than those extracted from dehulled seeds after roasting at 200°C, steaming at 100°C, roasting at 200°C plus steaming, or microwaving at 2450 MHz, except for TBA values of oil from microwaved seeds. After 35 d of storage at 65°C, the CD, p-AV, and TBA values of extracted oil from dehulled microwaved seeds were 17.72, 10.20, and 1.22, respectively, while those of their coated counterparts were significantly (P<0.05) different at 14.20, 16.47, and 1.26, respectively. Few significant changes were evident in the fatty acid composition of oil obtained from either coated and dehulled seeds subjected to different treatments. Nuclear magnetic resonance analyses found that R_ao (aliphatic to olefinic protons) and R_ad (aliphatic to diallylmethylene protons) ratios increased steadily over the entire storage period, which indicated progressive oxidation of unsaturated fatty acids.     

Reinforcement of maleated polyethylene/ground tire rubber thermoplastic elastomers using talc and wood flour

Maleated polyethylene (MAPE)/Ground tire rubber (GTR) thermoplastic elastomer with 50 vol % GTR was reinforced by incorporation of talc powder and wood flour. Scanning electron microscopy (SEM) reveals that maleated polyethylene (MAPE) has good compatibility with wood flour, but the adhesion with talc particles is weak. Tensile moduli of MAPE/GTR increase more significantly after inclusion of talc particles compared to wood flour. Prediction of the tensile modulus of hybrid MAPE/GTR/particle composites is successfully performed using a combination of Kerner and Halpin‐Tsai models. Elastic moduli are shown to depend strongly on both aspect ratio and level of particle dispersion in the matrix. Measurement of compression sets shows that elastic recovery of the compounds decreases after addition of solid particles. Samples having better particles/matrix compatibility show higher elastic recovery. Thermogravimetric analysis shows that inclusion of wood flour decreases thermal stability of compounds. Density and hardness of MAPE/GTR are also shown to increase after inclusion of particulate reinforcements. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40195.     

Impact compaction on a subgrade layer overlying deep deposit

Recent expansions of urban communities around the world have forced geotechnical engineers to deal with weak deep deposit for the construction of highways and roads. The current practice in estimating the level of field compaction is based on the results of a laboratory test, known as ‘Proctor’, where wide discrepancies are found between the laboratory-predicted and the field measurements. Impact compaction is a widespread soil-improvement technique that has been used with proven effectiveness. The technique is environmentally friendly, simple to apply and relatively inexpensive. This study presents a numerical model, which was developed to simulate the case of a dry thin subgrade layer overlying a deep deposit and subjected to impact compaction. The model is capable of measuring the total energy applied to the surface of the subgrade layer and its two components; namely the portion dissipated into the lower deposit and the portion remaining in the subgrade layer causing its compaction. A design guideline is presented.     

A bipolar implementation of the Beta neuron

The great flexibility of the Beta function and its universal approximation characteristics, make Beta basis function neural networks (BBFNNs) very useful. We present a hardware implementation of the Beta neuron. The proposed circuit was designed by using a standard bipolar technology. PSPICE simulations show the good concordance of the output of our circuit with the analytic Beta function. We also successfully integrated the electronic Beta neuron in the design of a BBFNN that approximates a nonlinear mapping.     

Improvement of operational control of internal precision of fire assay results for geological samples of gold-bearing ores

An algorithm of operational control of internal precision of fire assay results is proposed for geological samples of gold-bearing ores of the first group. The algorithm allows the labor inputs and the cost of this type of control activities to be reduced.     

A New and Accurate Modeling Technique for Glass Resistance in Multiphase Multielectrode Glass Furnaces

One of the design elements involved in sizing the electrical power equipment for glass furnaces is the determination of the glass resistances between the operating electrodes. All methods used for this purpose to date are approximate and are based on a simple model considering the resistance between only two electrodes at the time. This paper presents a technique to develop a resistance model for any general configuration of electrodes and supply voltages in glass furnaces. The technique is based on relating the glass conductivity as represented by Ohm's law to the electrostatic property as represented by Gauss's law. The resistance model is then derived in a matrix form using the bus admittance frame of reference. A digital computer program has been developed to implement the proposed technique and example results are presented.     

Estimation of generalized entropies with sample spacing

In addition to the well-known Shannon entropy, generalized entropies, such as the Renyi and Tsallis entropies, are increasingly used in many applications. Entropies are computed by means of nonparametric kernel methods that are commonly used to estimate the density function of empirical data. Generalized entropy estimation techniques for one-dimensional data using sample spacings are proposed. By means of computational experiments, it is shown that these techniques are robust and accurate, compare favorably to the popular Parzen window method for estimating entropies, and, in many cases, require fewer computations than Parzen methods.