An efficient, catalyst- and solvent-free, four-component, and one-pot synthesis of polyhydroquinolines on grinding

An efficient synthesis of polyhydroquinolines is achieved via a four-component reaction of aldehydes, dimedone, active methylene compounds, and ammonium acetate in one-pot under solvent-free conditions at room temperature on grinding. The present method does not involve any hazardous organic solvent or catalyst. The key advantages are the short reaction time, high yields, simple workup, and purification of products by non-chromatographic methods, i.e., by simple recrystallization from ethanol.     

High precision elimination of angular chirp in CPA laser systems with large stretching factors or high bandwidth

We present a novel and highly sensitive method to determine the residual angular dispersion of high-power laser pulses after stretching, amplification, and re-compression of the pulses in a chirped-pulse amplification laser system. This method is based on the intentional deflection of a part of the the spectrum within the compressor and aligning the centers of gravity of the two resulting and separated foci with largest possible spectral separation in the far field. Using this technique, we were able to reduce the residual angular dispersion on pulses to less than 0.05 μrad/nm in the vertical plane and less than 0.03 μrad/nm in the horizontal plane, respectively. With this method, it is possible to minimize the deviation of the actual peak intensity for the focused laser pulses to less than 2 % of its theoretical limit.     

The separation of GMP from milk whey using the modified chitosan beads

The cationic property of chitosan was used to adsorb glycomacropeptide (GMP) molecules from milk whey proteins. β-cyclodextrin was immobilized to native chitosan beads by cross-linking with 1,6-hexamethylene diisocyanate (HMDI). The resultant modified beads (CS-HMDI-BCD) presented superior adsorption affinity and capacity towards GMP. At pH 3.0, 90.23% of GMP was adsorbed with a maximum adsorption capacity corresponding to 12.87 mg of sialic acid/g-adsorbent. Desorption experiments showed that the modified beads could be regenerated and used in many cycles without significant decreases in the capacity and selectivity.     

Pressure dependence of the contact angle in a CO2-H2O-coal system

Carbon dioxide injection into coal layers serves the dual purpose to enhance coal bed methane production (ECBM) and to store CO2. The efficiency of this process is expected to be much higher if water is the non-wetting phase in the coal-water-gas system. Therefore, contact angles in the coal-water-CO2 system have been measured using the captive bubble technique in the pressure range between atmospheric pressure and 141 bar at a temperature of 45 degrees C. At atmospheric pressure the contact angle of a shrinking CO2 droplet increases with time, but stays below 90 degrees . At higher pressures (>2.6 bar) the contact angle increases beyond 90 degrees . The pressure dependence of the contact can be represented by theta=(111 degrees +/-10.5 degrees )+(0.17+/-0.14)P [bar]. The exceptional behavior at atmospheric pressure is possibly related to the stability of water patches on the coal surface. It is concluded that water is the non-wetting phase in this coal-water-CO2 system.     

Ultrahigh-quality photonic crystal cavity in GaAs

Membrane-based photonic crystal GaAs cavities with a double-heterostructure design were investigated. They show the highest quality factors for GaAs photonic crystal cavities to date, exhibiting quality factors higher than 10(5). The resonances of these cavities were fine-tuned in steps smaller than 2 nm by digital etching.     

Slow convergence of sequences of linear operators II: Arbitrarily slow convergence

We study the rate of convergence of a sequence of linear operators that converges pointwise to a linear operator. Our main interest is in characterizing the slowest type of pointwise convergence possible. This is a continuation of the paper Deutsch and Hundal (2010) [14]. The main result is a “lethargy” theorem (Theorem 3.3) which gives useful conditions that guarantee arbitrarily slow convergence. In the particular case when the sequence of linear operators is generated by the powers of a single linear operator, we obtain a “dichotomy” theorem, which states the surprising result that either there is linear (fast) convergence or arbitrarily slow convergence; no other type of convergence is possible. The dichotomy theorem is applied to generalize and sharpen: (1) the von Neumann–Halperin cyclic projections theorem, (2) the rate of convergence for intermittently (i.e., “almost” randomly) ordered projections, and (3) a theorem of Xu and Zikatanov.     

Notiz über die Ultrafiltration kolloider Lösungen von Organochrom-Verbindungen in Aethylenbromid

Ohne Zusammenfassung     

Supplier-initiated outsourcing: A methodology to exploit synergy in transportation

Over the last decades, transportation has been evolving from a necessary, though low priority function to an important part of business that can enable companies to attain a competitive edge over their competitors. To cut down transportation costs, shippers often outsource their transportation activities to a logistics service provider of their choice. This paper proposes a new procedure that puts the initiative with the service provider instead: supplier-initiated outsourcing. This procedure is based on both operations research and game theoretical insights. To stress the contrast between the traditional push approach of outsourcing, and the here proposed pull approach where the service provider is the initiator of the shift of logistics activities from the shipper to the logistics service provider, we will refer to this phenomenon as insinking. Insinking has the advantage that the logistics service provider can proactively select a group of shippers with a strong synergy potential. Moreover, these synergies can be allocated to the participating shippers in a fair and sustainable way by means of a so-called Shapley Monotonic Path of customized tariffs. Insinking is illustrated by means of a practical example based on data from the Dutch grocery transportation sector.     

Chlorine-isotopic exchange between lithium chloride and substituted 2-chloropyridine in homogeneous solution

The kinetics of chlorine-isotopic exchange between lithium chloride-36 and cyano- and nitro- substituted 2-chloropyridines were measured in sulpholane, acetone or methanol solution. Activating effects of ortho-nitro and ortho-azu substitution are compared: a nitro-group is 50 × as activating as the aza-group in the p-nitrochlorobenzene system, where as it is the aza-function which is 3 times as activating as the nitro group in the o-nitrochlorobenzene system. The effect of Me substituents placed ortho to an activating nitro-group was studied by comparing 2-chloro-3-cyano-5-nitropyridine and its 6-methyl- and 4,6-dimethyl-derivatives.