Determination of small amounts of zirconium--II : Analysis of refractory samples

In connection with the determination of small amounts of zirconium in complex samples, procedures have been developed for bringing various types of sample into solution and removing possible interferences, which procedures allow p-bromomandelic acid to be used as a precipitant for the final recovery of zirconium for gravimetric measurement. The applicability of these procedures, which are described in detail, has been investigated by the analysis for zirconium of a variety of refractory mineral and metallurgical samples.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32206/1/0000265.pd

Fuel cells--I. Propane on palladium catalyst

For the reaction at low temperatures of a gaseous hydrocarbon as a fuel gas at a negative electrode in a fuel cell, the choice of a suitable catalyst is of the first importance.In the present study, catalysts consisting of palladium reduced by hydrogen and palladium reduced by formate, supported on four types of porous skeleton disks (thin nickel, thick nickel and two types of carbon), were examined. In many cases, the electrodes were given a water-proofing treatment.The specific fuel cell used involved the prepared fuel electrode using gaseous propane, 30% KOH solution, a carbon-black air electrode and a temperature of 5O[deg]C We attempt to distinguish the behaviour of propane from that due to hydrogen contained in the electrode, mainly on the basis of the relationship between (a) electrode preparation and treatment and (b) the open-circuit potential behaviour of the fuel electrode.The repetition of small current discharges resulted in open-circuit potentials reaching steady high potentials and in electrodes exhibiting comparatively good dischargeabilities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32084/1/0000133.pd

Fuel cells--III. The propylene potential in low temperature cells

From the reproducible propylene potential observed at a platinum catalyst in 30% KOH solution, a potential of 0[middle dot]465 V (NHE) at 25[deg]C is calculated. The corresponding voltage for a propylene-oxygen cell is 0[middle dot]838 V.These values in conjunction with the observed temperature coefficient permit speculation regarding possible mechanisms and reactions in low-temperature propylene fuel cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32086/1/0000135.pd

Fuel cells--II. Propane and propylene on Adams' platinum catalyst

In order to control the quantity of previously adsorbed hydrogen in fuel electrodes to be used with hydrocarbons, the use of Adams' platinum catalyst was investigated. Preferred procedures for electrode preparation were developed. Adams' platinum oxide powder was intimately mixed with a silver powder and pressed to form a disk, which, fixed within a cell, was reduced with hydrogen in glacial HOAc and then treated with a water-proofing wax solution. Reduction could be stopped at a definite stage and the reduced electrode could be protected from air throughout all manipulative and measuring procedures. The potential behaviour of 15 electrodes reduced to differing degrees was studied in helium, propane, propylene and hydrogen at 80[deg]C.During flushing with propylene, the open-circuit potential increased quite rapidly after an induction period, which was related to the original degree of electrode reduction. The steady potential reached increased with the degree of reduction. The potential of an electrode initially saturated with hydrogen gradually decreased with propylene flushing, approaching a steady value.The good discharge behaviour observed for propylene far exceeded that due to hydrogen adsorbed during electrode preparation. Propylene flushing for more than 20 h was necessary to reach a steady potential. On interruption of the discharges, the potential returned to almost the initial potential. The steady potential may represent an equilibrium potential between propylene, electrode and electrolyte, and may be called a "propylene potential".Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32085/1/0000134.pd

Understanding the electromagnetic interaction of metal organic framework reactants in aqueous solution at microwave frequencies

Preparation of metal organic frameworks (MOFs) via microwave heating is becoming increasingly popular due to reduced reaction times and enhanced control of MOF particle size. However, there is little understanding about the detailed interaction of the electric field portion of the wave with reactants during the synthesis of MOFs. In order to overcome this lack of fundamental understanding, information about the dielectric properties of the reactants is required. In this work the dielectric constants (ε′) and loss factors (ε′′) of benzene-1,4-dicarboxylic acid (H2BDC; also known as terephthalic acid) and a number of M(III) (M = metal) salts dissolved in deionized water were measured as a function of frequency, temperature and concentration and with varying anions and cations. Dielectric data confirm the aqueous M(III) salts to be strong microwave absorbers, particularly at 915 MHz. M(III) salts with mono-anionic ligands (for example chlorides and nitrates) exhibit higher losses than di-anionic salts (sulfates) demonstrating that the former are heated more effectively in an applied microwave field. Of the M(III) salts containing either singly- or doubly-charged anions, those containing Fe(III) have the highest loss indicating that they will heat more efficiently than other M(III) salts such as Cr(III) and Al(III). Interestingly, H2BDC exhibits little interaction with the electric field at microwave frequencies

Molecular Epidemiology and Evolutionary Trajectory of Emerging Echovirus 30, Europe

In 2018, an upsurge in echovirus 30 (E30) infections was reported in Europe. We conducted a large-scale epidemiologic and evolutionary study of 1,329 E30 strains collected in 22 countries in Europe during 2016-2018. Most E30 cases affected persons 0-4 years of age (29%) and 25-34 years of age (27%). Sequences were divided into 6 genetic clades (G1-G6). Most (53%) sequences belonged to G1, followed by G6 (23%), G2 (17%), G4 (4%), G3 (0.3%), and G5 (0.2%). Each clade encompassed unique individual recombinant forms; G1 and G4 displayed >= 2 unique recombinant forms. Rapid turnover of new clades and recombinant forms occurred over time. Clades G1 and G6 dominated in 2018, suggesting the E30 upsurge was caused by emergence of 2 distinct clades circulating in Europe. Investigation into the mechanisms behind the rapid turnover of E30 is crucial for clarifying the epidemiology and evolution of these enterovirus infections.Peer reviewe

Molecular epidemiology and evolutionary trajectory of emerging echovirus 30, Europe

In 2018, an upsurge in echovirus 30 (E30) infections was reported in Europe. We conducted a large-scale epidemiologic and evolutionary study of 1,329 E30 strains collected in 22 countries in Europe during 2016-2018. Most E30 cases affected persons 0-4 years of age (29%) and 25-34 years of age (27%). Sequences were divided into 6 genetic clades (G1-G6). Most (53%) sequences belonged to G1, followed by G6 (23%), G2 (17%), G4 (4%), G3 (0.3%), and G5 (0.2%). Each clade encompassed unique individual recombinant forms; G1 and G4 displayed >= 2 unique recombinant forms. Rapid turnover of new clades and recombinant forms occurred over time. Clades G1 and G6 dominated in 2018, suggesting the E30 upsurge was caused by emergence of 2 distinct clades circulating in Europe. Investigation into the mechanisms behind the rapid turnover of E30 is crucial for clarifying the epidemiology and evolution of these enterovirus infections.Molecular basis of virus replication, viral pathogenesis and antiviral strategie