Liquid‐to‐solid ratio control as an advanced process control solution for continuous twin‐screw wet granulation

Assuring compliance of intermediate and final quality attributes in a continuous pharmaceutical manufacturing campaign is of utmost importance. Application of corrective actions might be required in real‐time. This work exemplifies the steps needed to identify a linear pulse transfer function for the dynamic behavior of the granule liquid‐to‐solid ratio (%w/w) at the end of the granulation unit of a commercial ConsiGma^TM‐25 production line. Near‐infrared spectroscopy was used to monitor the granule composition in‐line. The outcome for both the tracking and regulator problem using either conventional or model predictive control was implemented and evaluated. Dynamic setpoints were correctly followed and an RMSE of 0.25%w/w with respect to the setpoint was obtained when inducing artificial disturbances. Important practical challenges were also tackled. Examples are fouling, computational limitations, and the limited flexibility of the automation software. Applying the proposed advanced process control solution offers an answer to upstream material flow rate deviations. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2500–2514, 2018     

Homocoupling Defects in a Conjugated Polymer Limit Exciton Diffusion

Copolymers such as PCDTBT (poly(N‐9′‐heptadecanyl‐2,7‐carbazole‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole))) are commonly employed as donor material in bulk heterojunction solar cells. Recently, chemical defects such as homocouplings have been shown to form at the material synthesis stage, strongly reducing the short circuit current in organic photovoltaics. Here it is shown that both low molecular weight and homocoupling defects reduce the short circuit current of solar cells because of limited exciton diffusion. A model that unites and explains the influence of both chemical parameters with the distribution of conjugation lengths is proposed. The connection between limited exciton diffusion and short circuit current is revealed via kinetic Monte Carlo simulation of bulk heterojunctions. The findings are likely applicable for copolymers in general.     

Alkaline PF resins linear extension by urea condensation with hydroxybenzylalcohol groups

The linear increase of phenol–formaldehyde (PF) resins by reaction under alkaline conditions of the ortho- and para-hydroxybenzylalcohol groups of the PF resin with small molar percentages of urea was followed by model compounds reactions. Apparent rate constants of the reactions of urea with o-and p-hydroxybenzylalcohols were obtained. Both the ortho- and para-isomerides appeared to react faster with urea than for their autocondensation. The ortho-isomeride appears to react faster with urea than the para-isomeride, under alkaline conditions. Autocondensation under alkaline conditions instead appears to be faster in the case of p-hydroxybenzylalcohol. The properties of PF resins prepared with the addition of small amounts of urea appear to be consistent with what is observed in the model compounds reactions: Their gel times become faster and viscosity increases with increasing amounts of urea addition. © 1993 John Wiley & Sons, Inc.     

Never Mind The Content,Let'S Understand The Process: An Alternative Perspective On Recent Federal Urban Initiatives

The Federal Government's urban and regional initiatives have attracted considerable attention. Authors from diverse perspectives have commented on the increased prominence of urban issues within the Federal sphere (Bunker and Minnery 1993), the number and size of these programs (Orchard 1993), the ability of these initiatives to achieve their goals (Paris 1992; Badcock 1993a) and the plethora of reports on urban and related issues (Alexander 1994). Much of this research implicitly compares the policy initiatives of the 1990s with those of the Department of Urban and Regional Development (DURD) and all of it judges the Federal Government's initiatives against the author's perception of an appropriate outcome or outcomes. This paper argues that the objective or ‘rationalist’ approach to the Federal Government's activities in this policy milieu is in some respects mis-placed. While we must consider the consequences, it is folly to concentrate solely on outcomes and ignore the processes of policy formation and program development.     

Influence of ligno-cellulosic particles on tribological properties of boards

There are two main possibilities to substitute conventional wood material in the panel production: the use of wood of fast-growing trees plantations and/or the use of alternative ligno-cellulosic raw materials. Especially particleboards produced from the ‘‘energetic’’ willow present the same or better mechanical parameters compared to particleboards conventionally produced mainly from soft woods. Increasing bio-fuel production, mostly from rape, will cause an escalation of the rape cultivation area and, as a result, will augment the amount of waste (rape straw) to be utilized. The aim of this study was to verify the friction coefficient of the new board types in tribological contact with tools surfaces. The investigations were performed in situ. The results of the friction coefficient related to the tools surfaces as well as lingo-cellulose materials are presented.     

Neue epidural arbeitende Gehirndrucksonde — Labortests und Tierversuche — Stand der Entwicklung

The controlling of the intracranial pressure (ICP) is of significant importance for the treatment of patients suffering from cerebral trauma. There are two ways used in the clinical practice to measure the ICP, the intraventricular (inside the dura) and the epidural measurement (between the dura and the cranial-bone). From the viewpoint of accuracy of measurement the intraventricular measurement is to be preferred. However, from the medical point of view this method also involves bacteriological danger. For that reason the improvement of the epidural devices, based on an analysis of the at the time being used measurement devices, is described in detail in this paper.     

Harlots Or Heroes? The Role Of Contract Research Within Universities

‘Get inside the whale’ counsels Orwell. Give yourself over to the world-process, stop fighting against it or pretending that you control it; simply accept it, endure it, record it.     

Kinetics of adsorption of 2‐CEES and HD on impregnated silica nanoparticles under static conditions

Silica nanoparticles of high surface area (887.3 m²/g) were synthesized using aerogel route and, thereafter, impregnated with those reactive chemicals, which have already been proven to be effective against sulfur mustard (HD). Thus, developed adsorbents were tested for their potential by conducting studies on kinetics of adsorption of 2‐chloroethylethyl sulfide (2‐CEES) and HD under static conditions. Kinetics of adsorption was studied using linear driving force model and Fickian diffusion model. The kinetic parameters such as equilibration constant, equilibration capacity, diffusional exponent, and adsorbate‐adsorbent interaction constant were also determined. Trichloroisocyanuric acid impregnated silica nanoparticles (10% w/w) showed the maximum uptake of 2‐CEES (1824 mg/g) and HD (1208 mg/g). Values of diffusional exponent indicated the mechanisms to be Fickian and anomalous. Chemical interaction seemed to be another mechanism involved in the toxicant uptake rate. Hydrolysis, dehydrochlorination, and oxidation reactions were found to be the route of degradation of toxicants. © 2009 American Institute of Chemical Engineers AIChE J, 2009