Digital forensics of microscopic images for printed source identification

Multimedia Tools and Applications - When trying to identify a printed forged document, examining digital evidence can prove to be a challenge. In this study, microscopic images are used for printed...     

Synthesis and antimicrobial activity of some polymers derived from modified amino polyacrylamide by reacting it with benzoate esters and benzaldehyde derivatives

Functionalized polymers have gained much interest in the last decades. This is due to their functional groups and their polymer nature, which give them unique properties and more advantages than the corresponding small molecules. In this trend, we modified polyacrylamide by introducing an amino group in the side chain of the polymer by reacting it with ethylenediamine. The amine‐modified polymer was reacted with two classes of active compounds. The first group is aromatic aldehydes containing active groups such as p‐hydroxybenzaldehyde, vanillin, p‐chlorobenzaldehyde, and anisaldehyde. The second group is phenolic ester derivatives such as p‐hydroxymethylbenzoate, 2,4‐dihydroxymethylbenzoate, 2‐hydroxymethylbenzoate and 3,4,5‐trihydroxypropylbenzoate. The antimicrobial activity of these two classes were explored by cut plug method against Candida albicans SC5314, Aspergillus flavus, and Fusarium oxysporium as fungal organisms and Bacillus subtilis, Escherichia coli, and Staphylococcus aureus as bacterial organisms. It was found that the diameter of inhibition zone varied according to the active group in the modified polymer and the examined microorganism. In general, the modified polymers showed antimicrobial activity against the tested microorganisms. However, the polymer derivative of p‐chlorobenzaldehyde being the most effective on bacteria and fungi species. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

An ultraviolet phosphor from submicrometer-sized particles of gadolonium-doped yttrium oxide prepared by heating of precursors in a polymer solution

Gadolonium-doped yttrium oxide (Y₂O₃:Gd) was synthesized by simple heating of precursors in a polymer solution. This material is potentially useful as an ultraviolet source, since ultraviolet light is emitted when electron transition between energy states in Gd ions occurs. The grain sizes of the particles were found to be sub-micron down to several tens of nanometers. Optimum conditions for producing highly crystalline material with small grain and crystal sizes was investigated by varying the parameters for the synthesis, such as heating temperature, heating time, and dopant concentration. A heating temperature at 800 °C and a heating time of 30 min was optimum, i.e., appreciably high crystallinity and small grain sizes were produced. The particles produce ultraviolet light, peaking at 315 nm, and the intensity of the light depends on the dopant concentration. The maximum intensity was achieved at a dopant concentration of 5 to 10% at./at.     

Smart Bubble Sort: A Novel and Dynamic Variant of Bubble Sort Algorithm

In the present era, a very huge volume of data is being stored in online and offline databases. Enterprise houses, research, medical as well as healthcare organizations, and academic institutions store data in databases and their subsequent retrievals are performed for further processing. Finding the required data from a given database within the minimum possible time is one of the key factors in achieving the best possible performance of any computer-based application. If the data is already sorted, finding or searching is comparatively faster. In real-life scenarios, the data collected from different sources may not be in sorted order. Sorting algorithms are required to arrange the data in some order in the least possible time. In this paper, I propose an intelligent approach towards designing a smart variant of the bubble sort algorithm. I call it Smart Bubble sort that exhibits dynamic footprint: The capability of adapting itself from the average-case to the best-case scenario. It is an in-place sorting algorithm and its best-case time complexity is Ω(n). It is linear and better than bubble sort, selection sort, and merge sort. In average-case and worst-case analyses, the complexity estimates are based on its static footprint analyses. Its complexity in worst-case is O(n²) and in average-case is Θ(n²). Smart Bubble sort is capable of adapting itself to the best-case scenario from the average-case scenario at any subsequent stages due to its dynamic and intelligent nature. The Smart Bubble sort outperforms bubble sort, selection sort, and merge sort in the best-case scenario whereas it outperforms bubble sort in the average-case scenario.     

Investigation of a multiple trigger active disassembly element

An active disassembly (AD) shape memory polymer nanocomposite (SMPN) fastener that is released by application of a thermal and magnetic field has been developed. Provided is key data on the behavior of the fastener at specific temperature ranges and magnetic field strengths for exhibiting proper levels for disassembly. Furthermore, a comparison of this fastener to a previous shape memory polymer (SMP) fastener shows differences in the thermal shape memory ability of the SMP fastener and the thermal-magnetic ability of the SMPN fastener. The SMPN fastener is an option for disassembly and exhibits added control parameters to single trigger AD fasteners.     

Relative importance of Al(V) and reinforcement to the flexural strength of geopolymer composites

We prepared 1 cm × 1 cm × 10 cm geopolymer bars from sodium silicate and six commercial metakaolins, both unreinforced and reinforced with 20 wt% of 55-μm wollastonite (CaO·SiO₂) needles, to evaluate the relative contributions of five-coordinated aluminum in the metakaolin and the presence of a reinforcing phase to the flexural strength of geopolymers. Two metakaolins, with about 20 at% and lower of five-coordinated aluminum content, did not react sufficiently with our processing method and could not be tested. The flexural strengths of the other four geopolymers were similar at about 11–14 MPa unreinforced and 22–29 MPa reinforced. The effect of reinforcement on flexure strength is more significant than the choice of metakaolin provided that the metakaolin is reactive. The geopolymerization reaction depends on the amount of five-coordinated aluminum present in the metakaolin and is the primary difference between the samples that reacted and those that did not react.     

Emulsion stability of clove oil in chitosan and sodium alginate matrix

Clove oil was emulsified in 1% w/w chitosan (CC emulsions) and 2.5% w/w sodium alginate matrix (CA emulsions) containing Tween 80 as the surfactant. Different homogenization speeds (5,000, 10,000, 15,000 and 20,000 rpm) were used to produce the emulsions, and the stability of the emulsions during storage (29 days) was determined. The stability of the emulsions containing clove oil prior to the solidification process was assessed when chitosan and sodium alginate were used as encapsulating materials. Different homogenization speeds resulted in polydisperse emulsions with a size of 2–3 μm and 90% of stability after 29 days of storage. Different homogenization speeds did not significantly affect the concentrations of the active compounds contained in the emulsions. However, these concentrations changed significantly after 29 days of storage when sodium alginate was used to make the emulsions and the homogenization speeds were ≥ 10,000 rpm. High temperature caused by the high viscosity of the solution and high energy dissipation during homogenization suggested that the emulsions composed of sodium alginate were unstable. Chitosan enabled a longer processing time during the clove oil encapsulation process compared to sodium alginate, when emulsification by homogenization was used. The stability of the emulsion of the clove oil-in-chitosan matrix prior to the solidification step was superior.     

Energy Dispersive X-Ray Microanalysis of Elemental Distribution in Raw and Germinated Brown Rice Varieties

In this study, the mineral composition of germinated brown rice, brown rice, and white rice was evaluated. Brown rice grain was processed through a combination of chemical pretreatment and low oxygen treatment, after which germination was confirmed through imaging under a microscope. Using energy dispersive X-ray analysis, Mg, Al, and Cl were found to be slightly higher in germinated brown rice than in brown rice and white rice. These variations in the mineral content of germinated brown rice were attributed to the joint effect of the germination process and the prior soaking. The inability of energy dispersive X-ray to detect other minerals suggested that it was not sensitive and, hence, it was not suitable for studying elemental distribution in rice grains, or maybe the elements were not present in the rice grains studied.     

Quantum-well infrared photodetector structure synthesis: methodology and experimental verification

A numerical method for global optimization of quantum-well infrared photodetector (QWIP) performance parameters is presented and experimentally verified. The single-band effective-mass Schroedinger equation is solved by employing the argument principle method (APM) to extract both the bound and quasibound eigen-energies of the quantum heterostructure. APM is combined with a simulated annealing algorithm to determine a set of device design parameters such as potential barrier height V/sub i/, layer thickness d/sub i/, number of material layers N, total device length, applied bias V/sub Bias/ etc., for which the QWIP performance is within a predetermined convergence criterion. The method presented incorporates the effect of energy-dependent effective mass of electrons in nonparabolic conduction bands. The present model can handle many optimization parameters and can incorporate fabrication constraints to achieve physically realizable devices. In addition, the method is not limited to the optimization of absorption structures, and can be used for other intersubband devices such as electron-wave Fabry-Perot filters and quantum-cascade lasers. The strength and versatility of the present method are demonstrated by the design of a bicolor equal-absorption-peak QWIP structure, and experimental verification of the zero-bias absorption spectrum is presented.