Allowable Rates of Fluid Temperature Variations and Thermal Stress Monitoring in Pressure Elements of Supercritical Boilers

ABSTRACT

Allowable rates of fluid temperature changes in critical elements of supercritical steam boilers were determined assuming a quasi-steady state of temperature distribution in pressure components. A method was proposed for monitoring the thermal stresses in the critical pressure components.     

Non‐Glovebox Ethenolysis of Ethyl Oleate and FAME at Larger Scale Utilizing a Cyclic (Alkyl)(Amino)Carbene Ruthenium Catalyst

A ruthenium metathesis catalyst Ru1 bearing a cyclic (alkyl)(amino)carbene (CAAC) ligand is used in the ethenolysis reaction of biosourced 90% pure undistilled ethyl oleate or technical fatty acid methyl esters mixture with grade 3 ethylene, to yield 1‐decene and valuable terminal unsaturated 9‐decenoic acid ester. Under optimized conditions (25 ppm of catalyst Ru1 , 20 bar, 50 °C, 2 h, use of metal scavenger/quenching agent, SnatchCat), the title reaction proceeds with high productivity (up to 70% conversion) and selectivity, and is tested in scale up to 1 L, with the exclusion of a glovebox or Schlenk techniques usage, and the ethenolysis products are isolated by fractional distillation. In addition, a large‐scale synthesis of Ru1 is presented. Practical Applications: Decreasing availability of fossil organic feedstock and current policies of the European Union drives scientists to look for alternative sustainable sources of fine chemicals. In this context, olefin metathesis based ethenolysis of transesterified seed oils studied herein shows a significant potential as a sustainable way to obtain valuable products, such as 1‐decene and valuable terminal unsaturated 9‐decenoic acid ester. Unlike other published studies on ethenolysis, in the present work, the focus is on optimizing this reaction under industrially practical conditions, thus utilizing an air‐stable catalyst, technical grade oleic substrates, grade 3 ethylene, and excluding the use of a glovebox or Schlenk techniques.     

Virus-Like Particles Produced Using the Brome Mosaic Virus Recombinant Capsid Protein Expressed in a Bacterial System

Virus-like particles (VLPs), due to their nanoscale dimensions, presence of interior cavities, self-organization abilities and responsiveness to environmental changes, are of interest in the field of nanotechnology. Nevertheless, comprehensive knowledge of VLP self-assembly principles is incomplete. VLP formation is governed by two types of interactions: protein–cargo and protein–protein. These interactions can be modulated by the physicochemical properties of the surroundings. Here, we used brome mosaic virus (BMV) capsid protein produced in an E. coli expression system to study the impact of ionic strength, pH and encapsulated cargo on the assembly of VLPs and their features. We showed that empty VLP assembly strongly depends on pH whereas ionic strength of the buffer plays secondary but significant role. Comparison of VLPs containing tRNA and polystyrene sulfonic acid (PSS) revealed that the structured tRNA profoundly increases VLPs stability. We also designed and produced mutated BMV capsid proteins that formed VLPs showing altered diameters and stability compared to VLPs composed of unmodified proteins. We also observed that VLPs containing unstructured polyelectrolyte (PSS) adopt compact but not necessarily more stable structures. Thus, our methodology of VLP production allows for obtaining different VLP variants and their adjustment to the incorporated cargo.     

Visualization of particles arrangement during filling stage of polyamide 6 – metal insert injection molding

An isotactic polypropylene filled with talc and mica particles was used for visualization of molten polymer flow lines during filling of mold cavity with metal insert. The talc particles orientation in polypropylene matrix was followed by scanning electron microscopy. For the quantification of platelet particles orientation in molten polymer flow localized near metal wall, the Herman's function was applied. An existence of regions with well oriented, randomly organized talc particles depending on the shape and cross‐section of the channels, was found and reported. The domain with the most disorganized platelet particles was detected in the region where polymer streamed around the sharp corner of the metal insert. Such a kind of disarranged region could be the weakest part of the whole injection molded polymeric element. POLYM. ENG. SCI., 59:E271–E278, 2019. © 2019 Society of Plastics Engineers     

Executive coaching: The need for standards of competence.

Psychologists working in the emerging competency area of "executive coaching" must promote a more complete understanding of what constitutes effectiveness in this arena—particularly when the expected outcome is sustained behavior change. Experienced psychologists must accept accountability for the need to inform and educate corporate decision makers about the core skills, competencies, experience, and related professional issues critical for successful outcomes. These educative efforts are essential if executive coaching for sustained behavior change is to be established as a respected consultative area adding value to organizationally based leadership development initiatives. The purpose of this article is to begin the dialogue among psychologists about the need to become more proactive in their educative efforts with these decision makers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Progression of the curve in boys who have idiopathic scoliosis

The prevalence of curve progression was evaluated in 210 boys who had idiopathic scoliosis. A minimum age of eight years, a deformity of at least 10 degrees, and radiographic follow-up of one year or progression of the curve within the first year of follow-up were the criteria for inclusion in the study. Of the 210 patients, sixty-eight (32 per cent) had progression of 10 degrees or more. Four of the five patients who had had an initial curve of 50 degrees or more subsequently had a spinal arthrodesis. The risk of progression was significantly greater for patients who were at an earlier Risser stage (p < 0.002) and for those who were younger (p < 0.005). The risk of progression was also greater for patients who had had a larger curve at the time of presentation; of the sixty-three boys for whom the Risser grade was 1, 2, 3, 4, or 5 when they were first seen and who had a curve of 25 degrees or more, twenty (32 per cent) had progression, compared with only two (5 per cent) of the thirty-eight who had a Risser grade of 1, 2, 3, 4, or 5 and a curve of 24 degrees or less. Of the thirty-four patients for whom the Risser grade was 4 when they were first seen, five (15 per cent) had progression.(ABSTRACT TRUNCATED AT 250 WORDS)     

Queueing in high-performance packet switching

The authors study the performance of four different approaches for providing the queuing necessary to smooth fluctuations in packet arrivals to a high-performance packet switch. They are (1) input queuing, where a separate buffer is provided at each input to the switch; (2) input smoothing, where a frame of b packets is stored at each of the input line to the switch and simultaneously launched into a switch fabric of size Nb×Nb; (3) output queuing, where packets are queued in a separate first-in first-out (FIFO) buffer located at each output of the switch; and (4) completely shared buffering, where all queuing is done at the outputs and all buffers are completely shared among all the output lines. Input queues saturate at an offered load that depends on the service policy and the number of inputs N, but is approximately 0.586 with FIFO buffers when N is large. Output queuing and completely shared buffering both achieve the optimal throughput-delay performance for any packet switch. However, compared to output queuing, completely shared buffering requires less buffer memory at the expense of an increase in switch fabric size     

Multiple-access protocols: fairness in heterogeneous systems

We propose a distributed reservation protocol for high-speed, star-based, local-communication systems with heterogeneous users. The users have different delay, throughput, and priority requirements, and each user has knowledge of only its own traffic mix. At light loads, the usual delay overhead of reservation schemes can be eliminated. Also, the probability of correct reservation reception is improved: it is only necessary to detect the presence or absence of a signal since reservation signals do not carry address information or the desired amount of channel time. Users know the value of a global reservation counter, which specifies the amount of transmission time acquired by a reservation. The protocol can support both circuit- and packet-switched traffic (e.g., integrated voice and data)