Obfuscated Fuzzy Hamming Distance and Conjunctions from Subset Product Problems

We consider the problem of obfuscating programs for fuzzy matching (in other words, testing whether the Hamming distance between an $n$-bit input and a fixed $n$-bit target vector is smaller than some predetermined threshold). This problem arises in biometric matching and other contexts. We present a virtual-black-box (VBB) secure and input-hiding obfuscator for fuzzy matching for Hamming distance, based on certain natural number-theoretic computational assumptions. In contrast to schemes based on coding theory, our obfuscator is based on computational hardness rather than information-theoretic hardness, and can be implemented for a much wider range of parameters. The Hamming distance obfuscator can also be applied to obfuscation of matching under the $\ell_1$ norm on $\mathbb{Z}^n$. We also consider obfuscating conjunctions. Conjunctions are equivalent to pattern matching with wildcards, which can be reduced in some cases to fuzzy matching. Our approach does not cover as general a range of parameters as other solutions, but it is much more compact. We study the relation between our obfuscation schemes and other obfuscators and give some advantages of our solution

Pyrolysis of Phragmites Australis and characterization of liquid and solid products

In this study, an investigation was conducted in order to find out whether Phragmites Australis can be utilized in various ways by means of pyrolysis in a tubular fixed-bed system. To this end, a study was carried out to investigate the effect of the pyrolysis temperature, heating rate, sweep gas flow rate and the size of Phragmites Australis on pyrolysis. The maximum tar yield was achieved at 550 °C pyrolysis temperature, a heating rate of 25 °C/min and a sweeping gas flow rate of 100 ml/min. The average chemical composition of the tar obtained was established by elemental analysis and its structural analysis was conducted by 1H NMR spectrum and FTIR spectrum. Moreover, elemental and proximate analyses were conducted of the chars obtained in all experimental conditions to collect information on their structure. © 2008 The Korean Society of Industrial and Engineering Chemistry.2003-13-02-08The writer should like to express her gratitude to Zonguldak Karaelmas University for the Scientific Research Fund (Project No.: 2003-13-02-08) for their financial assistance at the project stage

The examination of liquid, solid, and gas products obtained by the pyrolysis of the three different peat and reed samples

Samples from four different parts of the peat deposits in the Yeniçaga (Bolu, Turkey) region were pyrolyzed in a fix-bed pipe type furnace at a heating rate of 2° C/min and at a temperature of 600°C. The analyses for the structure of the liquid products obtained were performed by elemental analysis, 1H-NMR spectroscopy and Fourier transform infrared spectroscopy. The structure of the solid products was determined by proximate and ultimate analyses, while the composition of gas products was found by gas chromatography. Copyright © 2008 by ASME

Removal of Pb(II) and Ni(II) ions from aqueous solution by peat

The purpose of this study is to investigate the tendency of peat to adsorb Pb(II) and Ni(II) ions from an aqueous solution. The experiments conducted aimed at studying the effect of initial metal ion concentration, adsorbent dosage, aqueous solution pH and aqueous solution temperature in the single-component aqueous solutions. In addition, a binary-component aqueous solution was used to investigate the effects of contact time and desorption. According to the results of the experiments carried out under these conditions, it has been established that the optimum peat dosage is 2 g peat/L, the optimum pH 6, the optimum initial metal ion concentration 5 mg/L Pb(II) and 5 mg/L Ni(II), the aqueous solution temperature 20°C, and contact time 60 min. According to the results of all experimental conditions, the adsorption capacity was found to be Pb(II)>Ni(II). It has been established that the adsorption isotherm is well-suited to the Langmuir isotherm. © by PSP 2007

Pyrolysis by thermogravimetric analysis of blends of peat with coals of different characteristics and biomass

In this study, an investigation was carried out into the thermal behaviours of peat, reed, lignite, bituminous coal and blends of these with peat. The blends were prepared in 20:80, 40:60, 60:40, 80:20. The samples were pyrolysed in a TG analyzer in a nitrogen atmosphere (50 mL/ min) at temperatures ranging from 25 to 900 °C. Using TG/DTG graphs, variations were investigated, which occurred in reaction intervals, percent of weight loss, peak temperatures and maximum devolatilization rate. The activation energy (E) and pre-exponential constant (A) were calculated using the Arrhenius type kinetic model. © 2007 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved

Coal desulfurization using natural Ca-based sorbents

Lignite with a high organic sulfur content was desulfurized by pyrolysis performed at temperatures ranging from 650 to 950°C. An investigation was carried out on the effect of calcium-based sorbents such as lime, limestone, and dolomite on removing sulfur during pyrolysis in the presence of N2 and CO2 gases. Limestone and dolomite proved more effective than lime and more sulfur was removed in an atmosphere of CO2 than in an atmosphere of N2.Fundamental Research Fund of Shandong University: ZKU-AFP-2002-13-02-03Received 4 April 2004; accepted 22 July 2004. The author expresses her gratitude to Zonguldak Karaelmas University Research Fund (ZKU-AFP-2002-13-02-03) for financial assistance at the project level. Address correspondence to Hale Sutcu, Chemistry Department, Zonguldak Karaelmas University, 67100 Zonguldak, Turkey. E-mail: [email protected]

Pyrolysis of peat: Product yield and characterization

Pyrolysis of peat obtained from Yeniçaga, Bolu, Turkey was conducted in a fixed-bed tube furnace under various conditions, and variations in the structure of the char, tar and gas products were examined. The chars produced were studied by proximate and ultimate analyses. The maximum tar yield of 20.41% was obtained at a heating rate of 20 °C/min, a temperature of 450 °C, a sweeping gas flow rate of 100 ml/min and a 0.5-2.0 mm size range. The chemical composition of the tar was examined by elemental analysis, FTIR spectroscopy, 1H-NMR spectroscopy and column chromatography. The chemical composition of the tar with dense aliphatic structure was established to be CH1.22O0.25N0.02. The composition of the gases obtained at a heating rate of 20 °C/min for the 0.5-2.0 mm size range was examined by gas chromatography. © 2007 Springer.2003-13-02-08The writer should like to express her gratitude to the Zonguldak Karaelmas University Scientific Research Fund (Project No: 2003-13-02-08) for their financial assistance at the project stage

Optimization of some parameters in column flotation and a comparison of conventional cell and column cell in terms of flotation performance

In this study, a comparative evaluation was made between column and mechanical flotation cells for fine coal cleaning. In addition, the optimum values of operating parameters were examined, which are important to achieve a desired separation performance in column flotation, such as the frother concentration, the collector dosage, the froth thickness, the wash water rate, the air rate and the feeding rate. The coal sample was collected from a classifying cyclone overflow stream consisting of nominally - 130 µm material. Ash, volatile mater, fixed carbon and total sulfur contents of the sample were found to be 47.50%, 20.80%, 31.70% and 0.75%, respectively. Comparison of the column and mechanical flotation results indicated that column flotation was considerably more efficient than mechanical flotation for fine coal cleaning. High froth thickness and wash water addition during column flotation made it possible to obtain cleaner coals. The column flotation produced a 15.60% product ash with a 50.92% clean coal yield and 81.85% combustible recovery. © 2007 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved