Studies concerning charged nickel hydroxide electrodes IV. Reversible potentials in LiOH,NaOH, RbOH and CsOH

The variation of reversible potential E_r with log a_moh and has been studied for several nickel hydroxide/oxyhydroxide couples in various alkali hydroxides. Both activated and deactivated -phase couples show only a small dependence ofE _r with log_moh (or where known) in LiOH, NaOH, RbOH and CsOH electrolytes. The change in MOH content on oxidation/reduction is found to be about 0.1 mol MOH per two-electron transfer and is the same as found previously in KOH. These results confirm that the bulk oxidized -phase lattice is devoid of alkali cation although a small quantity may be adsorbed by the surface. On the other hand both activated and deactivated /-phase couples show a marked dependence of 0.45 mol MOH per two-electron transfer in LiOH, NaOH and RbOH (at concentrations > 0.5 m), also in good agreement with earlier data for KOH. On the basis of these results a general stoichiometry can be inferred for the -phase, namely M_0.32NiO₂ · 0.7H₂O where M=Li⁺, Na⁺, K⁺ or Rb⁺. Measurements imply that the Cs⁺ ion or the Rb⁺ ion at low concentration (<0.5 m) do not enter the interlayer structure of the -phase. This behaviour is thought to be related to the low Rb-O and Cs-O bond strengths afforded by the -phase structure.     

Critical solution point and chain dimension of branched-polystyrene solutions

Summary Critical solution point and chain dimension were measured for branched polystyrene(BPS) in solution as a function of molecular weight(M) and compared with those for linear polystyrene(LPS). The critical concentration _c of BPS was quite different from that of LPS at a fixed M, but the same at a fixed overlap-concentration ^*, i.e., plots of _c vs. ^* fall on a single straight line for both BPS and LPS (gf_c ^*). Reduced critical temperature _c defined by gt_c=(–T_c)/ [T_c: critical temperature, : the -temperature] was related to _c as _{c c} ² for BPS, whereas _{c c} for LPS.     

Syntheses and properties of polyimides based on bis(p-aminophenoxy)biphenyls

Three biphenyl unit-containing diamines,4,4-bis(p-aminophenoxy)biphenyl (III_a), 2,2-bis(p-aminophenoxy)biphenyl (III_b), and 3,3,5,5-tetramethyl-4,4-bis(p-aminophenoxy)biphenyl (III_c), were prepared by the chlorodisplacement ofp-chloronitrobenzene with 4,4-biphenol (I_a), 2,2-biphenol (I_b), and 3,3,5,5-tetramethyl-4,4-biphenol (I_c), respectively, giving the corresponding bis(nitrophenoxy) compounds II_a-c, followed by catalytic reduction with palladium (Pd) and hydrazine. Three series of polyimidesp-PI,o-PI, and Me-PI were prepared from diamines III_a-c and aromatic tetracarboxylic dianhydrides via a two-stage procedure that included ring-opening polyaddition to give poly(amic acid)s followed by thermal cyclodehydration to polyimides. The resultant three series of poly(amic acid)s had inherent viscosities of 1.09–2.83, 0.78–1.93, and 1.55–3.09 dL/g, respectively. Almost all the poly(amic acid)s could be solution-cast and thermally converted into transparent, flexible, and tough polyimide films. All the polyimides were characterized by solubility, tensile test, wide-angle X-ray scattering measurements, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Effects of the structures of aromatic diamines and dianhydrides on the properties of polyimides were investigated.     

Laminar radial flow electrochemical reactors. III. Electroorganic sysnthesis

This paper investigates the performance and design of three laminar radial flow electrochemical cells (the capillary gap cell, stationary discs; the rotating electrolyzer, co-rotational discs; the pump cell, one disc rotating and the other stationary). Modeling of a competing electrosynthesis pathway is described — the methoxylation of furan. The model developed incorporates convective, diffusive and migrative influences with three homogeneous and two electrodic reactions. Two sizes of reactors are considered and the performance of the different reactor types analyzed as a function of size. The superiority of the rotational cells is illustrated for this reaction scheme compared to both the capillary gap cell (CG) and a parallel plate reactor (PPER). Scale-up criteria are scrutinized and two approaches to laminar radial flow reactor scale-up are investigated. The one suggested herein shows that Taylor number, residence time,IR drop and rotational Reynolds number must all be accounted for even with a fairly simple electrosynthesis pathway. A quantitative evaluation of this scale-up procedure is included.Nomenclature a gap width (m) - C dimensionless concentration - D diffusion coefficient (m² s^-1) - Pe Peclet number ( _c a/D) - Q volumetric flow rate (m³ s^-1) - r dimensionless radius - R radius (m) - Re Reynolds number ( _c a/v) - Re rotational Reynolds number (R ₀ ² /v) - t time (s) - residence time of reactor - _r dimensionless radial velocity - _z dimensionless axial velocity - V volume (m³), velocity (m s^-1) and voltage - z dimensionless axial distance Greek symbols Taylor number ((a ² )/4v)^1/2 - ratio of characteristic lengths (a/R ₀) - constant - v kinematic viscosity (m² s^-1) - angular velocity (rad s^-1) - reference value - Thiele moduli      

Studies concerning charged nickel hydroxide electrodes I. Measurement of reversible potentials

Reversible potentials (E _R) have been measured for nickel hydroxide/oxyhydroxide couples over a range of KOH concentrations from 0·01–10 M. It is shown that the couples derived from the parent- and-Ni(OH)₂ systems can be distinguished by the relative change in KOH level on oxidation and reduction. In the case of couples derived from the-class of materials a dependence of 0·470 moles of KOH per 2e change is found compared with 0·102 moles of KOH per 2e change for the-class of materials. Couples derived from the- and-Ni(OH)₂ systems can be encountered in a series of activated and de-activated forms having a range of formal potentialsE ₀ . Activated. and de-activated-Ni(OH)₂/-NiOOH couples are found to lie in the range 0·443–0·470 V whilst-Ni(OH)₂/-NiOOH couples lie in the range 0·392–0·440 V w.r.t. Hg/HgO/KOH. It is demonstrated for de-activated,-Ni(OH)₂/-NiOOH couples thatE _R is independent of the degree of oxidation of the nickel cation between states of charge of 25% and 70%. SimilarlyE _R is constant for states of charge between 12% and 60% for activated-Ni(OH)₂/-NiOOH couples. The constant potential regions are considered to be derived from heterogeneous equilibria between pairs of co-existing phases both containing nickel in upper and lower states of oxidation. Differences inE ₀ between the activated and de-activated couples are considered to be related to the degree of order/disorder in the crystal lattice.     

Note of the estimation of the Θ temperature and Ψ parameter from the critical temperature data

Summary Critical values of the polymer volume fraction _2,c and the interaction parameter _c have been computed for the case that the equation for the chemical potential of solvent contains terms _{c 2} ³ and _{c 2} ⁴ in addition to ₂ ² . For 0 _c 1/3, the limits for infinite chain length are _2,c = 0 and _c = 0.5. Quite different results are obtained for _c > 1/3, _2,c being finite and _c lower than 1/2. Conclusions for the estimation of the temperature and the entropy-of-dilution parameter are discussed.     

Development of pheromone lure for monitoring field populations ofEoreuma loftini (Lepidoptera: Pyralidae)

Formulations of Mexican rice borer (MRB) pheromone components were more effective in capturing males in fields of sugarcane when dispensed from rubber septa than when evaporated from four other substrates. Concentrations of 0.63–10.0 mg of total pheromone per lure were effective over a 112-day period when formulated in rubber septa in a ratio of 811.3 of (Z)-13-octadecenyl acetate, (Z)-11-hexadecenyl acetate, and (Z)-13-octadecenal, respectively. Component ratios of 411.3 and 811.3 were equally effective in capturing male MRB, but efficacy decreased with higher relative concentrations of (Z)-13-octadecenyl acetate.Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.     

The impedance of the Ledanché cell. I. The treatment of experimental data and the behaviour of a typical undischarged cell

The impedance spectrum of an undischarged commercial Leclanché cell (Ever Ready type SP11) is presented in the forms of the Sluyters plot and the modified Randies plot. The decomposition of the experimental cell impedances into the component parts has been achieved using a computer. The decomposition process and the component processes representing the overall cell behaviour are described.List of symbols R _s in-phase component of (experimental) electrode impedance - R _t charge transfer resistance referred to nominal area of Zn ( cm²) - 1/(C _s) out-of-phase component of (experimental) electrode impedance - angular frequency (= 2f) - R resistance of electrolyte solution - charge transfer resistance - C _L double layer capacitance - C _DL double layer capacitance of electrode referred to nominal area of Zn (F cm^–2) - j –1 - Warburg coefficient - D factor in Equations 1 and 2 - C _s R _s calculated values ofC _s andR _s (first approximation) - C _s R _s calculated values ofC _s andR _s (refined values taking into account the additional network) - C _s R _s calculated values of C_s andR _s (refined values taking into account porosity) - _x resistive part of additional series component (parallel connection) - C _x capacitance part of additional series component (parallel connection) - D factor in Equations 6 and 7     

Application of the accelerated Tafel plot technique to corrosion kinetics: Role of double layer through simulation

Results on the simulated -t transient response of an actively corroding system under accelerated Tafel plot (ATP) conditions have revealed the influence of input parameters (i, ) and system parameters (C _dl,i _corr andb) and explained the observed dependence of kinetic parameters (arrived at on the basis of the intercept-slope method) on in certain time domains. New improved methods, which eliminate such dependence and give uniform corrosion rate data over all time domains, are described in the paper.Nomenclature ATP accelerated Tafel plot - transfer coefficient - b Tafel slope (V) - C _d double layer capacitance (F cm^–2) - i initial value of the exponentially decaying current (A) - E _c corrosion potential (V) - overpotential (V) - n overpotential corresponding to maximum in -t transient (V) - F Faraday constant (C mol^–1) - i _corr corrosion current density (A cm^–2) - n number of electrons involved in charge transfer step - p intercept of ATP (V) - R gas constant (JK^–1 mol^–1) - R _p polarization resistance ( cm²) - S slope of ATP, i.e. d/dt (V) - S _av average of theS values at > _el (V) - S _meas slope of the linear -t region, i.e. d/dt (Vs^–1) - T temperature (K) - t time (s) - t _m time corresponding ton _m in the -t transient (s) - time constant of the exponentially decaying current pulse (s) - _el electrode time constant given byR _p C _d (s)     

Impedance parameters and the state-of-charge. II. Lead-acid battery

The determination of the state-of-charge of the lead-acid battery has been examined from the viewpoint of internal impedance. It is shown that the impedance is controlled by charge transfer and to a smaller extent by diffusion processes in the frequency range 15–100 Hz. The equivalent series/parallel capacitance as well as the a.c. phase-shift show a parabolic dependence upon the state-of-charge, with a maximum or minimum at 50% charge. These results are explained on the basis of a uniform transmission-line analog equivalent circuit for the battery electrodes.Nomenclature Battery This word is used synonymous with the word cell - R _p equivalent parallel resistance () - R _s equivalent series resistance () - ¦Z¦ modulus of impedance () - C _p equivalent parallel capacitance (F) - C _s equivalent series capacitance (F) - a.c. phase-shift (radians or degrees) - 2f - f a.c. frequency (Hz) - R resistance of electrolyte solution and separator () - ¯C double layer capacity (F) - W diffusional (Warburg) impedance () - R _t resistance due to polarization () - energy transfer coefficient - T absolute temperature (K) - R gas constant - F Faraday constant - C _O ⁰ bulk concentration of the oxidant - C _R ⁰ bulk concentration of the reductant - D _O diffusion coefficient of the oxidant - D _R diffusion coefficient of the reductant - Warburg coefficient - N number of pores/area - A active area of the electrode (cm²) - S state-of-charge - a anode - c cathode - L inductance - I _o exchange current     

Sex pheromone chemistry of the western spruce budwormChoristoneura occidentalis Free

SCOT capillary Chromatographic and SCOT capillary chromatographic-mass spectrometic analyses of gland washes and effluvia of virgin femaleChoristoneura occidentalis Free, have been conducted with both a diapausing and nondiapausing strain of this insect. The following compounds were identified in gland washes and effluvia in both strains:E andZ11–14Ald,E andZ11–14Ac,E andZ11–14OH and 14Ald, 14Ac, and 14OH. The average aldehyde: acetate: alcohol ratio found by analysis of single glands by virgin females (nondiapausing strain) was 170.73. Analysis of virgin female effluvia gave this ratio as 1038 (diapausing strain: %Z=8, 11, 15, respectively) and 1036 (nondiapausing strain: %Z=8, 11, 12, respectively). The saturated components were generally 1–2% of theE isomer in each case. Comparisons of EAG responses of bothC. occidentalis andC. fumiferana toE11–14Ald,E11–14Ac andE11–14OH were made. Correlations with both laboratory and field data previously published were also made betweenC. fumiferana andC. occidentalis.Lepidoptera: Tortricidae.     

Sex pheromone of aPlanotortrix excessana sibling species and reinvestigation of related species

The sex pheromone of aPlanotortrix excessana sibling species was investigated. Females were found to produce eight potential pheromone components: dodecyl acetate, tetradecyl acetate (14OAc). (Z)-5-tetradecenyl acetate (Z5-14OAc), (Z)-7-tetradecenyl acetate (Z7-14OAc), (Z)-9-tetradecenyl acetate, hexadecyl acetate, (Z)-7-hexadecenyl acetate, and (Z)-9-hexadecenyl acetate. When these compounds were bioassayed using field-trapping and wind-tunnel techniques, only 14OAc,Z5-14OAc, andZ7-14OAc were found to be behaviorally active. The sex pheromone glands of females of other species including,Planotortrix MBS,Planotortrix M,P. notophaea, Ctenopseustis servana, and aC. obliquana sibling species, were also found to containZ5-14OAc orZ7-14OAc, singly or in combination. In the case ofPlanotortrix M, the addition ofZ7-14OAc to the previously identified sex pheromone blend ofZ5-14OAc and 14OAc was found to increase trap captures of male moths of this species. Thus in these New Zealand species (and in some Australian species),Z5-14OAc andZ7-14OAc appear to be utilized in combination in pheromonal communication just as (Z)-11-tetradecenyl acetate and (E)-11-tetradecenyl acetate are used by many species of Holarctic Tortricidae in the tribe Archipini.Lepidoptera: Tortricidae: Tortricinae.     

Flow-through and flow-by porous electrodes of nickel foam Part III: theoretical electrode potential distribution in the flow-by configuration

This paper deals with the theoretical potential distribution within a flow-by parallelepipedic porous electrode operating in limiting current conditions in a two-compartment electrolytic cell. The model takes into account the influence of the counter-electrode polarization and of the separator ohmic resistance. The results show that the design of the porous electrode requires the knowledge of the solution potential distribution within the whole cell volume.Nomenclature a _c specific surface area per unit volume of electrode - C ₀ entrance concentration (y=0) - C _s exit concentration (y=y ₀) - E electrode potential (= _M – _S ) - E _o equilibrium electrode potential - F Faraday number - i current density - mean mass transfer coefficient - K parameter [a _ea zFi _oa/(_a RT)]^1/2 - L porous electrode thickness - n number of terms in Fourier serials - P specific productivity - Q volumetric flow-rate - mean flow velocity based on empty channel - V constant potential - V _R electrode volume - x thickness variable - X conversion - y length variable - y ₀ porous electrode length - z number of electrons in the electrochemical reaction Greek symbols parameter - parameter - ionic electrolyte conductivity in pores - _S solution potential - _M matrix potential ( _M = constant) - parameter [=n/y ₀ - parameter [=+K] - overpotential Suffices a anodic - c cathodic - eq equilibrium - s separator - S solution     

Kinetics and Mechanism of Copolymerization of α-terpineol with Methylmethacrylate in Presence of Azobisisobutyronitrile as an Initiator

The radical copolymerization of -terpineol with methyl-methacrylate in xylene at 80±0.1C for 50 minutes in the presence of azobisisobutyronitrile (AIBN) follows ideal kinetics and results in the formation of a functional and random copolymer. The activation energy is 33 KJ/mole. The IR spectrum and NMR spectra of the copolymer(s) shows the bands at 1750 and 3400 cm^–1 for ester group of methylmethacrylate and alcoholic group of -terpineol and peaks at 3 to 4 for methoxy group and at 6.5 to 7.5 due to alcoholic group of methylmethacrylate and -terpineol repectively. The values of reactivity ratios, calculated by Kelen–Tüdos method, are r ₁ (MMA) = 0.18 and r ₂ (-terpineol) = 0.046. The Alfrey-Price; Q–e parameters for -terpineol has been calculated as 0.149 and 2.486. The mechanism of copolymerization has been elucidated and it is concluded that the double bond present in the monocyclic ring of -terpineol is an active site for copolymerization and the alcoholic group of -terpineol remain to give functional copolymer.     

Chemical modification of copoly(methylsilylene/1,4-phenylene) by Pt-catalyzed hydrosilation reactions with functionally substituted alkenes

Copoly(methyl-3-biphenoxypropylsilylene 1,4-phenylene), copoly(methyl-3-cyanopropylsilylene 1,4-phenylene), copoly(methyl-3-ethoxypropylsilylene 1,4-phenylene), copoly(methyl-3-phenoxypropylsilylene 1,4-phenylene), and copoly(methyl-4,7,10,13-tetraoxatetradecanylsilylene 1,4-phenylene) have been prepared by platinum-catalyzed hydrosilation graft reactions between poly (methylsilylene 1,4-phenylene) and appropriate functionally substituted alkenes. These polymers have been characterized by¹H,¹³C, and²⁹Si NMR as well as by FT-IR and UV-vis spectroscopy. The molecular weight distribution of these polymers has been determined by gel permeation chromatography (GPC), and their glass transition temperatures (T _e) by DSC.     

Electrochemical behaviour of viologen-cyclodextrin inclusion complexes. The case of non-alkyl group substituted viologen

The electrochemical behavior of non-alkyl substituted viologen, 4,4-dibenzyl bipyridinium (BzV), 4,4-dicyanophenyl bipyridinium (CyV) and -,-,-cyclodextrin (, , -CD) was studied using cyclic voltammetry and a spectroelectrochemical method. It was found that BzV and Fe(CN) ₆ ^4– formed a charge-transfer (CT) complex with a ratio of 21 and the colour of the solution faded with the addition of an electrolyte. This behaviour is the same as in then-heptyl viologen and ferrocyanide system [1]. BzV, -CD and -CD formed an inclusion complex only in the reduced state, whilst BzV and -CD formed an inclusion complex in both the oxidized and the reduced state. An EC scheme in which a chemical reaction follows an electrochemical reaction was considered to predominate in the BzV and -, -CD systems, while a CE scheme in which a chemical reaction preceded an electrochemical reaction predominated in the BzV and -CD system. On the other hand, CyV was found to form an inclusion complex with -, -, -CD in both the oxidized and the reduced states. therefore a CE scheme was considered to predominate in the CyV--, -, -CD systems.     

Redundancy in a chemical signal: Behavioral responses of maleTrichoplusia ni to a 6-Component sex pheromone blend

The flight response of maleTrichoplusia ni was observed in a flight tunnel to a sex pheromone blend composed of six components:Z7–12Ac, 12Ac,Z5-12Ac, 11-12Ac,Z7-14Ac, and Z9-14Ac. The number of males reaching a 3000-g source of this blend was > 95%, equal to that observed to female glands and significantly greater than with the previously identified two-component blend (Z7-12Ac + 12Ac). In subtraction tests, all five-component blends, with the exception of the blend lacking the primary componentZ7-12Ac, and several four-component blends elicited similar peak levels of upwind flight, source contacts, and hairpencil displays to that observed with the six-component blend. We characterize the substitution of certain minor components for one another as a form of redundancy in the chemical signal and suggest that it contributes to response specificity and signal recognition in males. The results also support the concept that the full blend of components acts as a unit to influence male behavior at all phases of the response. Individual minor components were not responsible for eliciting specific behaviors in the sequence.     

Investigation of sex pheromone components of female asian corn borer,Ostrinia furnacalis (Hübner) (Lepidoptera: Pyralidae) in Taiwan

(E)-12-Tetradecenyl acetate (E12–14OAc), (Z)-12-tetradecenyl acetate (Z12–143nOAc), and tetradecanyl acetate (14OAc) were extracted and identified as major chemical components from female tips of the Asian corn borer,Ostrinia furnacalis (Hübner) (Lepidoptera: Pyralidae) in Taiwan, with a combined wash ratio of 483715 and an individual female ratio of 453916. The average amount ofE12-,Z12–14OAc and 14OAc in each female gland was 6.6±4.6, 5.8±3.5, and 2.4±1.7 ng/female, respectively. The mixture of these three synthetic chemicals not only gave strong activities in male antennae but also could catch significantly more males than virgin females in field-trapping tests. The field test also showed no significant difference in trapping ability among the three-component Taiwan formulations, the two-component Taiwan formulation (Z12–14OAc andZ1214OAc, 5347), and the Japan formulation (Z12–14 OAc andE 12–14OAc, 3:2).     

Investigation of the role of diterpenes produced by marine pulmonatesTrimusculus reticulatus andT. conica

The intertidal pulmonate limpetTrimusculus reticulatus, which is found in caves or crevices along the California coast, was previously reported to contain two novel diterpenoids, 6-isovaleroxylabda-8,13-dien-7,15-diol (1) and 2,7-diacetoxy-6-isovaleroxylabda-8,13-dien-15-ol (2). Dissection of the animals prior to extraction revealed that the diterpenoids were concentrated in the mantle, foot, and mucus, but not in the viscera. The presence ofT. reticulatus or its mucus was toxic to veliger larvae of the sabellariid reef-building tube wormPhragmatopoma californica. The major diterpenoid1 was responsible for the observed larvicidal activity. Protection against overgrowth by settling invertebrate larvae is important for the survival of this sessile filter-feeding pulmonate. A related pulmonate,T. conica, which was found in similar intertidal habitats in New Zealand, contained 6-acetoxy-7-isovaleroxylabda-8,13-dien-15-oic acid (3) and 1,7,12,18-tetraacetoxy-cholest-5-en-3-ol (4). The diterpene3 was also localized in the foot, mantle, and mucus ofT. conica but was not larvicidal toP. californica.     

A model of the electrochemical behaviour within a stress corrosion crack

A mathematical model of the electrochemical behaviour within a stress corrosion crack is proposed. Polarization field, crack geometry, surface condition inside the crack, electrochemical kinetics, solution properties and applied stress can be represented by the polarization potential and current, the electrochemical reactive equivalent resistance of the electrode, the change in electrolyte specific resistance and surface film equivalent resistance, respectively. The theoretical calculated results show that (i) when anodic polarization potential is applied, the change in the crack tip potential is small; (ii) when cathodic polarization potential is applied, the crack tip potential changes greatly with the applied potential; (iii) the longer the crack, the smaller the effect of the applied potential on the crack tip potential in both anodic polarization and cathodic polarization conditions. The calculated results are in good agreement with previous experimental results.Notation coordinate, from crack mouth (on the metal surface) to crack tip (cm) - y y = s _L L/(s ₀ – s _L) + L – , function of (cm) - y ₀ y ₀ = s _L L/(s ₀ – s _L) + L (cm) - V polarization potential (V) - galvanic potential of electrode (V) - ₁ galvanic potential of electrolyte (V) - t sample thickness (cm) - w sample width (cm) - S _L crack tip width (cm) - S _o crack mouth width (cm) - L crack length (cm) - s() crack width at position (cm) - _lo specific resistance of electrolyte, as a constant ( cm) - _s specific resistance of metal ( cm) - (, y) specific resistance of electrolyte, varies with potential and crack depth ( cm) - R _b (, y) electrochemical reactive equivalent resistance of electrode, varies with potential and crack depth () - R ₁ electrolyte resistance () - R _s metal resistance () - r(, y) surface film equivalent resistance, varies with potential and crack depth () - r _o surface film equivalent resistance, as a constant () - I _o total polarization current (A) - I net polarization current from integrating 0 to in Fig. 2 (A) - polarization overpotential (V) - _a anodic polarization overpotential (V) - _c cathodic polarization overpotential (V) - Euler's constant