Chemical Reactivity Test Research Articles

Comparative Study of Starch-Based Bioplastic from Banana (Musa acuminata) peel (SBB) Incorporated with Commercialized and Extracted Chitin

Abstract: The study produced extracted Chitin from Asian Green Mussel (Perna viridis) and Golden Apple Snail (Pomacea canaliculate) shells using two-way chemical extraction process; deproteinization and demineralization. The extracted and commercialized Chitin were characterized through Fourier Transform Infrared (FTIR) Spectroscopy to determine and compare the functional groups present. Starch-based bioplastics were produced using banana peel starch (BPS) incorporated with commercialized chitin and chosen chitin extract which is from AGM. The bioplastics were tested for its morphology through Scanning Electron Microscopy (SEM), physical property through air test, chemical properties through biodegradability test, chemical reactivity test, water vapor transmission rate (WVTR) test, water absorption test and flammability test, and mechanical property through tensile strength test. Four treatments were carried out using 1%, 2%, 3%, and 4% by weight chitin addition. The control SBB does not contain any chitin. All treatments were prepared using constant amount of BPS, PVA solution and glycerol. Based from the results, chitin addition improves the strong acid resistance, water-barrier properties, and tensile strength of the SBB. It was found out that the best treatment was T3 of AGM which has a WVTR of 73.9868 g/m2 , dissolved in water in an average of 6.1783 days, and has a tensile strength of 64286.3777 Pa

Energy, safety, and absorption efficiency evaluation of a pilot-scale H2S abatement process using MDEA solution in a coke-oven gas

This study models an H2S removal unit for steel-manufacturing coke-oven gas and suggests optimal operating conditions and safety analysis for absorption and regeneration columns. Sensitivity analysis was performed on H2S removal to identify the minimum methyldiethanolamine (MDEA) solution flow rate using 99% H2S removal as a constraint and minimal heat duty. The optimized L/G ratio and regeneration column pressure were investigated accordance with change in H2S emission limit or desulfurization efficiency (99–99.9%), to reflect the different usage of COG. For the absorption column, the MDEA solution and heating duty were expected to be reduced in optimal conditions by 35% and 23% respectively when absorbent to gas mass ratio was decreased from 2.0 to 1.3, respectively. The most effective operating pressure for the distillation column was 2.5 bar (Basis pressure: 1.2 bar) based on a trade-off between reboiler energy and the H2S remaining in the recycle stream. According to optimization result with variation in efficiency, the higher optimized L/G ratio, higher reboiler duty, higher intermediate heat exchanger duty, and lower optimized regenerator pressure were required to maintain higher efficiency with different COG utilization. To ensure safe operating conditions, chemical reactivity tests were conducted for mixture of chemicals. Additionally, Gas dispersion analysis predicted the concentration and distance of gas spread to ensure safety from gas leak accident.

Ligand-Based Storage of Protons and Electrons in Dihydrazonopyrrole Complexes of Nickel.

A newly developed dihydrazonopyrrole ligand and corresponding Ni complexes have been synthesized and thoroughly characterized. Electrochemical studies and chemical reactivity tests show that these complexes can reversibly store both electrons and protons, or equivalently H-atoms, via ligand-based events. The stored H-atom equivalent can be transferred to small molecules such as acetonitrile or oxygen. Furthermore, this series of complexes can adopt a variety of different coordination modes. In addition to one e- reactivity, the two e- electrophilic oxidation of phosphines is also demonstrated. Taken together, these results show that dihydrazonopyrrole complexes represent a geometrically and electronically flexible scaffold for controlling the flow of both electrons and protons.

Synthesis and characterization of the oxygen-deficient perovskite BaFe0.9-xY0.1CoxO3-δ (0 ≤ x ≤ 0.15)

BaFe0.9-xY0.1CoxO3-δ (0≤x≤0.15) is shown to adopt the cubic perovskite structure at temperatures up to 1400K in air. The oxygen vacancy concentration increases with both cobalt content and temperature, with BaFe0.75Y0.1Co0.15O2.35 being the most oxygen-deficient composition observed. At 700K the conductivity is ∼2Scm−1 across the whole composition range. Measurements of the Seebeck coefficient show that holes are the dominant carrier. The coefficient of thermal expansion is essentially constant above 800K, but not at lower temperatures. Chemical reactivity tests, along with the coefficient of expansion, show that these perovskites would not be suitable electrodes for fuel cells with fluorite electrolytes but they might serve as permeable membranes in catalytic reactors.

Fabrication and electrochemical characterizations of Nd2NiO4+δ-Ce0.8Gd0.2O2−δ composite cathodes for anode-supported intermediate temperature solid oxide fuel cells

Nd2NiO4+δ (NNO)-Ce0.8Gd0.2O2−δ (CGO) composites were investigated as cathodes for intermediate temperature solid oxide fuel cells (IT-SOFCs). Planar NiO-YSZ anode-supported cells in size of 50 mm×50mm were fabricated with YSZ as the electrolyte. The effects of sintering temperature and the relative proportions of NNO and CGO on the cell performance were investigated in combination with chemical reactivity tests of NNO-YSZ and NNO-CGO. NNO-CGO composite cathodes were successfully sintered on YSZ electrolyte at 1000°C. By using La0.6Sr0.4CoO3−δ (LSC) as current collector, the cell with 70NNO-30CGO composite cathode sintered at 1000°C exhibited the highest power density of 620mWcm−2 (at 0.7V) and the lowest polarization resistance of 0.302Ωcm2 at 800°C. Short-term durability studies revealed that the degradation of cell performance was attributed to the crack formation on the LSC current collector layer and the delamination between NNO-CGO cathode layer and LSC current collector layer.

Synthesis and preliminary study of La4BaCu5O13 + δ and La6.4Sr1.6Cu8O20 ± δ ordered perovskites as SOFC/PCFC electrode materials

La4BaCu5O13+δ (LBCu) and La6.4Sr1.6Cu8O20±δ (LSCu) oxygen deficient perovskites, synthesized by a Pechini-type gel combustion method, have been investigated as potential cathode materials for IT-SOFC applications. The thermal stability and chemical compatibility with SOFC/PCFC electrolyte materials are examined using X-ray diffraction technique. For both compounds, no structural change is detected in air until 900°C. The evolution of cell parameters with temperature shows thermal expansion coefficients (TEC) of 17.3×10−6K−1 and 12.1×10−6K−1 for LBCu and LSCu, respectively. For LBCu, the formation of oxygen vacancies is evidenced between 700 and 900°C in air. Chemical reactivity tests with several SOFC electrolyte materials reveal a high reactivity of both cuprates with YSZ, GDC and, to a lesser extent, with LSGM. On the other hand, and contrary to what occurs for LSCu, LBCu presents an excellent chemical compatibility with doped barium cerate and zirconate, opening further perspectives for this material as possible SOFC or PCFC cathode. LBCu material presents a quite high electrical conductivity with metallic-type behavior.

Synthesis and thermal stability of Re2Zr2O7, (Re=La, Gd) and La2(Zr1−xCex)2O7−δ compounds under reducing and oxidant atmospheres for thermal barrier coatings

Rare-earth zirconates and cerates have attracted particular interest for thermal barrier coating (TBC) applications due to their advantageous thermal properties, such as a low conductivity and efficient phase stability at elevated temperatures. This study focuses on synthesising La 2 Zr 2 O 7 , Gd 2 Zr 2 O 7 , La 2 Ce 2 O 7− γ and La 2 (Zr 0.7 Ce 0.3 )O 7− γ compounds via two soft chemistry processes, alkoxide and citrate synthesis. Thermal analysis, X-ray diffraction (XRD) and scanning electron microscope observations were used to analyse the powder after calcinations under air. Chemical reactivity tests under a reducing atmosphere were performed at 1400 °C and investigated by XRD analysis. It was found that the lanthanum and gadolinium zirconates are the most stable and interesting materials under an Ar (g) /3%H 2(g) atmosphere.

Cooperativity between two selected RNA Pdases in the synthesis of Pd nanoparticles

We have made the surprising discovery that the crystallinity of nanoparticles formed from solutions containing RNA depends upon the presence of sequence mixtures. That is, a single sequence selected from the original random RNA sequence library produced mostly amorphous hexagonal nanoparticles, while a combination of sequences that emerged from the selection yields crystalline material as determined by SAED. To our knowledge this is the first example in which two biomolecules (RNA, DNA, or peptides) selected in vitro work together to provide a unique chemical outcome. In addition, this article provides a rigorous examination of the chemistry of Pd nanoparticle formation using RNA and the organometallic precursor complex Pd2(DBA)3 (DBA is dibenzylideneacetone). These studies have identified the specific conditions required for the successful RNA-mediated synthesis of Pd nanoparticles from aqueous solutions (10% THF : 90% H2O) containing Pd2(DBA)3, as well as conditions that led to anomalous results. A variety of techniques were employed to characterize materials formed under different solution conditions including SEM, AFM, TEM, selected area electron diffraction (SAED), and a chemical reactivity test. These analysis methods support the formation of Pd particles by RNA mediation when accounting for and controlling the important variables in the execution of the experiments. It is now clear that nanoparticles formed from RNA sequences isolated viain vitro selection can be dependent on many factors and it is understood that the specific sequence or sequence mixtures must be taken into account to fully understand RNA mediation of nanoparticle formation.

Runaway reactions in aluminum, aluminum chloride, HCl, and steam: An investigation of the 1998 CONDEA Vista explosion in Maryland

AbstractOn October 13, 1998, an explosion and fire occurred at a 3,000 gallon reactor in the linear alkyl benzene (LAB) process at the CONDEA Vista plant in Maryland. Process materials released from the various vessels and piping fueled a subsequent fire that took approximately two hours to extinguish. The accident investigation revealed that, prior to the explosion, the bottom of the reactor was plugged with approximately 180 gallons of a sludge‐like mixture of coarse aluminum powder, aluminum chloride, and various hydrocarbons. The explosion occurred approximately 10 minutes after steam was introduced at the bottom of the reactor in an effort to break up the sludge accumulation.A series of reduced‐scale chemical reactivity tests were completed to investigate the potential reactions between steam and manufactured sludge similar to what had accumulated inside the reactor. Rapid runaway chemical reactions were observed after steam was injected into this mixture, and pressures in excess of 45 barg (660 psig), and temperatures in excess of 700° F were recorded before the test vessels ruptured. A review of possible chemical reactions between steam, aluminum, and aluminum chloride confirms that the predominant reaction mechanism is the exothermic hydrolysis of aluminum chloride to produce HCl vapor. Significant amounts of hydrogen gas can also be generated as the aluminum reacts with the acid/steam mixture after it is stripped of its protective oxide coating. The investigators concluded that the root cause of this accident was direct and sustained contact between the steam and accumulated sludge at the bottom of the reactor.

The effect of chemical and surface properties of hydrogenated carbon overcoats on the tribological performance of rigid magnetic disks

The chemical and surface properties of hydrogenated carbon films were evaluated by using various surface and bulk analytical techniques. These properties were then related to the disks' tribological performance. The techniques used included hydrogen forward scattering, Fourier transform infrared spectroscopy, Raman spectroscopy, resistance measurements, contact angle measurements, electron spectroscopy for chemical analysis, drag tests, and a chemical reactivity test. As the hydrogen content of the carbon films increased from 16 to 53%, the carbon bonding character changed from sp/sup 2/ to sp/sup 3/. This change in chemical properties improved the film's mechanical and physical properties, which, in turn, led to improved mechanical durability in the drag tests. Incorporation of H into the films passivated the carbon dangling bonds at the film's surface. This change at the films' surface prevented oxidation and improved the performance of the films in the chemical reactivity test.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The chemical reactivity test - a compatibility screening test for explosives

The chemical reactivity test is used to evaluate the compatibility of explosives with other materials. This test has been in use at Pantex for more than 15 years, and during this time several improvements have been made in the test apparatus. The basic test apparatus consists of a gas chromatograph with subambient temperature programming. A special inlet and a calibration system were designed and added to the chromatograph. Samples are conditioned in specially designed sample holders. A description of the test apparatus is given and data from a variety of different types of materials with explosives are discussed. Examples of various types of information which can be obtained from the test are also discussed.

Chemische Konstitution und mutagene Wirkung

A number of bifunctional chloroethylamines with different basic structure has been tested for their mutagenic effectiveness in Drosophila. The test substances were applied orally to 1–3 day old males of the stock Berlin wild of Drosophila melanogaster and the ratios of recessive X-chromosomal lethal mutations were ascertained by means of the Base-method. In experiments to modify the mutagenic effects of phenyl-lost-derivatives by substitution in para-position to the lost nitrogen we obtained the following sequence of mutagenicity (R=substituent): $$R = NH_2 > H > OCH_3 \sim CHO > Cl = control.$$ . The differences in mutagenicity were partly restricted to specific stages of the cycle of spermatogenesis. There was no correlation between mutagenicity and chemical reactivity. The mutagenicity increased proportionally to duration of feeding. The mutagenic activity of the cytostatically ineffective and only extremely weakly reactive p-Bis-(β-chloroethyl)-amino-benaldehyde (C.B. 1077) shows that chemical reactivity tests are not suited for the estimation of the mutagenicity of drugs by routine. In the series of the bifunctional N-lost-cyclophosphamides the mutagenicity decreased in the series B 801>B 518≧B 525 according to the chemical reactivity. The differences between the mutagenic activity of B 801 and the other substances were especially significant in mature spermatozoa. The sensitivity of the stages of the cycle of spermatogenesis was tested by fractionated matings against the mutagenic impulse of the test substances. Generally the observed mutations were due do changes, induced in postmeiotic and meiotic germ cell stages. Mature spermatozoa proved especially sensitive against p-Bis-(β-chloroethyl)-amino-phenylalanine (C.B. 1128), while on the other hand the efficiency of Cytoxan on this stage was relatively weak. The toxicity of the aromatic nitrogen-mustards was neither correlated with the mutagenic activity nor with the chemical reactivity of these compounds. The most active mutagen had the weakest and the weakest mutagen the highest toxicity. Simultaneous application of C.B. 1128 and 1-cysteine led to a drastical decrease of the mutation rate in comparison with the C.B. 1128 control; previous cysteine treatment was ineffective. The feeding of cysteine respectively cysteamine before X-irradiation with 2,000 R respectively 3,000 R had no inhibiting effect on the X-ray induced mutations.