An orienteering model for the search and rescue problem

In this paper, we propose a new model for the search and rescue problem. We focus on the case of a single airborne search asset through a connected space and continuous time with a maximum travel time \(T\) . The intent is to maximize the detection of a cooperative target (search and rescue). The proposed model is based on the assumption of existing a priori information (e.g., result of information fusion process) to establish a spatial distribution of probability of containment in possible geographic locations. The possibility area is defined using a cut threshold on the probability of containment and the search path as well as the allocation of the level of effort to each region in the search space is obtained based on an orienteering model. We illustrate the application of the proposed model on an empirical example.     

Botanical Oils Isolated from Simmondsia chinensis and Rosmarinus officinalis Cultivated in Northern Egypt: Chemical Composition and Insecticidal Activity against Sitophilus oryzae (L.) and Tribolium castaneum (Herbst)

The rice weevil, Sitophilus oryzae (L.), and the red flour beetle, Tribolium castaneum (Herbst), are key stored-product pests in Egypt and worldwide. The extensive use of synthetic insecticides has led to adverse effects on the environment, human health, and pest resistance. As a result, environmentally friendly pest management alternatives are desperately required. The botanical oils of jojoba, Simmondsia chinensis (L.), and rosemary, Rosmarinus officinalis L. plants growing in Egypt were extracted, identified by gas chromatography/mass spectrometry (GC–MS), and evaluated for their insecticidal activity against S. oryzae and T. castaneum. The main constituents identified in BOs were carvyl acetate (20.73%) and retinol (16.75%) for S. chinensis and camphor (15.57%), coumarin (15.19%), verbenone (14.82%), and 1,8-cineole (6.76%) for R. officinalis. The S. chinensis and R. officinalis BOs caused significant contact toxicities against S. oryzae and T. castaneum adults, providing LC₅₀ values of 24.37, 68.47, and 11.58, 141.8 ppm at 3 days after treatment (DAT), respectively. S. chinensis oil exhibited significant fumigation toxicity against both insects; however, it was more effective against S. oryzae (LC₅₀ = 29.52 ppm/L air) than against T. castaneum (LC₅₀ = 113.47 ppm/L air) at 3 DAT. Although the essential oil (EO) of R. officinalis significantly showed fumigation toxicity for S. oryzae (LC₅₀ = 256.1 and 0.028 ppm/L air at 1 and 3 DAT, respectively), it was not effective against T. castaneum. These BOs could be beneficial for establishing IPM programs for suppressing S. oryzae and T. castaneum.     

Facile synthesis and antimicrobial evaluations of some novel pyrazolo[3,4-b]selenolo[3,2-e]pyrazines and their related heterocycles

A new series of pyrazolopyrazinoselenolotriazolopyrimidines was synthesized by a facile method based on condensation of 5-amino-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]selenolo[3,2-e]pyrazine-6-carbonitrile ( 3 ) with triethyl orthoformate followed by intramolecular cyclization with hydrazine to afford 7-amino-8-imino-3-methyl-1-phenyl-1,8-dihydro-7H-pyrazolo[3″,4″:5′,6′]pyrazino[2′,3′:4,5] selenolo[3,2-d]pyrimidine ( 5 ). The latter compound was utilized as a multipurpose precursor for the construction of other new triazoles fused to the pyrazolopyrazino- selenolopyrimidine moiety. Alternatively, acetylation and chloro-acetylation of compound 3 using acetic anhydride and chloroacetyl chloride yielded the acetyl amino 11 and chloroacetamido 12 derivatives, respectively. Compound 12 underwent nucleophilic substitution upon reaction with morpholine to provide the morpholinyl acetamide 13 . Furthermore, the pyrazolopyridoselenolopyrazine ring system 14 was synthesized by the reaction of the o-amino-carbonitrile 3 with malononitrile. Assignment of the chemical structures for the new compounds was confirmed depending on elemental and spectral techniques. On the other hand, most of the synthesized compounds revealed promising results against various bacterial and fungal strains.     

Water‐in‐Crude Oil Emulsions in the Burgan Oilfield: Effects of Oil Aromaticity,Resins to Asphaltenes Content (R/(R+A)), and Water pH

Asphaltenes and resins separated from emulsion samples collected from Burgan oil field were used with heptane‐toluene mixtures as model oil to study the effect of oil aromaticity, resin content, and pH of the aqueous phase on the stability of water in model emulsions. It was confirmed that, as long as the asphaltenes are completely solubilized, increasing aromaticity leads to less stable emulsions. A consistent correlation between emulsion stability and relative resin mass content (R/(R+A)) was observed for all three of the field samples. There was a sharp decrease in stability when the R/(R+A) value exceeded 0.75. Emulsion stability was enhanced at high pH and possibly at very low pH (<2).     

Studies on the Uptake of Rare Earth Elements on Polyacrylamidoxime Resins from Natural Concentrate Leachate Solutions

Synthesis of poly(acrylamidoxime) resin from polyacrylonitrile performed with different crosslinking ratios 2, 5, and 10 wt% of divinylbenzene as crosslinking agent, using methylbenzoate and dioctylphthalate as pore producing solvent, the reaction mixture occurred under nitrogen. Studies carried out on diluted solution from rare earth elements (REEs) concentrate contains impurities as Cu²⁺, Ni²⁺, Zn²⁺, Fe³⁺, Al³⁺, Si⁴⁺, Th⁴⁺, U⁶⁺, Ca²⁺, and K⁺. Changing some parameters as pH of the solution, time of feeding and type of acid as HCl, HNO₃, H₂SO₄. The adsorption efficiency of resin is in the order pH 6 > pH 5 > pH 4 > pH 2 with excluding pH 6 due to the precipitation of some of REEs with the impurities and complete precipitation of Dy ion during pH adjustment, the adsorption in HNO₃ > HCl > H₂SO₄ media.     

Nickel(II) complexes of 3-acetyl-4,5-dihydro-1,2,4-triazole hydrazones

3-Acetyl-1,2,4-triazole hydrazones (3b,c) and methylhydrazone (4d) were prepared by reacting triazoles (1b–d) with an excess of hydrazines at room temperature. Square planar nickel(II) complexes (8b,c) of (3b,c) were obtained from their reaction with Ni(OAc)₂ in a 2:1 mol ratio in EtOH at room temperature. The spectral data suggest structures (8b,c) for the obtained complexes, which result from ring opening of the triazole ring followed by recyclization to give the 5-arylhydrazono-2,3-dihydro-4H-1,2,4-triazine ligand (7b,c). The reaction of triazole methylhydrazone (4d) with Ni(OAc)₂ in EtOH resulted, however, in the formation of the starting triazole (1d). All new compounds were characterized by elemental analysis, i.r., ¹H-n.m.r. ¹³C-n.m.r. and hrms.     

Evaluation of sorption of uranium onto metakaolin using X-ray photoelectron and Raman spectroscopies

Metakaolin prepared from a natural clay mineral ore of aluminium kaolinite is a promising low cost and high activity aluminosilicate material that has been investigated for studying the sorption behavior of uranium. Here, metakaolin was characterized using X-ray photoelectron spectroscopy (XPS) and the effects of pH, contact time and initial metal ion concentration on its sorption behavior were studied. The sorption process was found to initially be rapid (∼60% at time 0 min) but became slower with time; equilibrium was established within 24 h (∼80% sorption). The data were applied to study the kinetics of the sorption process. The Langmuir and Dubinin-Radushkevich (D-R) sorption isotherms were used to describe partitioning behavior for the system at room temperature. The binding of metal ions was found to be pH dependent, with optimal sorption occurring at pH 5. The retained metal ions were eluted with 5 mL of 0.1 M HNO₃. Raman spectroscopy and XPS were used to evaluate the sorption mechanism of U(VI).     

Synergistic effects of ion-pairing in the enantiomeric separation of basic compounds with cyclodextrin derivatives in nonaqueous capillary electrophoresis

The enantiomeric separation of various kinds of basic pharmaceuticals has been investigated in nonaqueous capillary electrophoresis (NACE) systems using an ion-pairing reagent in combination with cyclodextrins (CDs). The simultaneous addition to the methanolic background electrolyte (BGE) of (+)-S-camphorsulfonate or alkanesulfonates and an anionic beta-cyclodextrin derivative, heptakis(2,3-dimethyl-6-sulfato)-beta-cyclodextrin (HDMS-beta-CD), led to partial or complete enantioresolution in most cases. In the absence of ion-pairing reagent, the enantiomeric resolution obtained with this CD derivative was most often completely lost or strongly reduced, indicating the important role of ion-pairing in the chiral recognition mechanism in these NACE systems. The influence of the nature and concentration of the counterion and the anionic CD derivative on the enantioseparation of basic compounds was studied. Synergistic effects between these two kinds of charged additives were clearly observed.     

Synthesis and antimicrobial activity of substituted [(pyrazol‐4‐yl)methylene]hydrazono‐2,3‐dihydrothiazoles and their sugar derivatives

A number of new [(pyrazol‐4‐yl)methylene]hydrazono‐2,3‐dihydrothiazole derivatives, their sugar hydrazones and N‐glycosides were synthesized. Furthermore, N‐substituted oxygenated alkyl and hydroxyl derivatives and 1,3,4,‐oxadiazoline acyclic nucleoside analogs were prepared. The newly synthesized compounds were tested for their antimicrobial activities and showed moderate to high inhibition activities. J. Heterocyclic Chem., (2012).