Unconventional Conditions Research Articles

Upgrading softwood bleached kraft pulp to dissolving pulp by cold caustic treatment and acid-hot caustic treatment

Two chemical processes for hemicellulose extraction have been applied on a softwood kraft pulp in an attempt to convert paper pulp into dissolving grade pulp. The cold caustic extraction process (CCE) was performed under conventional and unconventional conditions. Alkali concentration ranged from 3% to 12% and temperature from 25 to 110°C. As expected, the results showed that NaOH concentration had a predominant effect on xylan and glucomannan removal. The effect of temperature was more complex since the best removal was observed below 40°C or above 80°C. The unexpected good results obtained at high temperature would be due to the contribution of some alkaline degradation. Under the best conditions, 80% of the xylan and 60% of the glucomannan were removed. The cellulose II content was measured by solid state NMR spectroscopy. Formation of cellulose II increased with the concentration of caustic soda and was correlated to the extraction of hemicellulose. A second process consisting in an acid stage at high temperature (up to 150°C) followed by a hot caustic extraction (A-HCE) was also tested. Promising results in terms of hemicellulose removal were obtained when temperature in A was above 140°C. This might be due to a combination of acidolysis during A and peeling reactions during HCE. However, cellulose was partly depolymerized because of the severity of the A step. The two processes were compared in the context of getting to a viscose grade dissolving pulp.

Aeroelastic analysis of versatile thermal insulation (VTI) panels with pinched boundary conditions

Launch vehicle design and analysis is a crucial problem in space engineering. The large range of external conditions and the complexity of space vehicles make the solution of the problem really challenging. The problem considered in the present work deals with the versatile thermal insulation (VTI) panel. This thermal protection system is designed to reduce heat fluxes on the LH2 tank during the long coasting phases. Because of the unconventional boundary conditions and the large-scale geometry of the panel, the aeroelastic behaviour of VTI is investigated in the present work. Known available results from literature related to similar problem, are reviewed by considering the effect of various Mach regimes, including boundary layer thickness effects, in-plane mechanical and thermal loads, non-linear effects and amplitude of limit cycle oscillations. A dedicated finite element model is developed for the supersonic regime. The models used for coupling the orthotropic layered structural model with Piston Theory aerodynamic models allow the calculations of flutter conditions in case of curved panels supported in a discrete number of points. An advanced computational aeroelasticity tool is developed using various dedicated commercial softwares (CFX, ZAERO, EDGE). A wind tunnel test campaign is carried out to assess the computational tool in the analysis of this type of problem.

Cesium carbonate as efficient catalyst for chemoselective transesterification of β-ketoesters under conventional and unconventional conditions

Transesterification of β-ketoesters with different alcohols has been studied under conventional and unconventional conditions using the simple desktop chemical cesium carbonate as catalyst. These methods enabled transesterification of β-ketoesters in good yields with dramatic rate acceleration and reduced reaction times. The procedures which used unconventional methods, for example sonication and microwave irradiation, are highly promising compared with conventional procedures.

High-Throughput Optimization of Ir-Catalyzed C–H Borylation: A Tutorial for Practical Applications

With the aid of high-throughput screening, the efficiency of Ir-catalyzed C-H borylations has been assessed as functions of precatalyst, boron reagent, ligand, order of addition, temperature, solvent, and substrate. This study not only validated some accepted practices but also uncovered unconventional conditions that were key to substrate performance. We anticipate that insights drawn from these findings will be used to design reaction conditions for substrates whose borylations are difficult to impossible using standard catalytic conditions.

2P314 デザインされたDNA高次構造体の環境安定性評価(28.バイオエンジニアリング,ポスター,日本生物物理学会年会第51回(2013年度))

2P314 デザインされたDNA高次構造体の環境安定性評価(28.バイオエンジニアリング,ポスター,日本生物物理学会年会第51回(2013年度))

Sequential Decision Analysis of Fire Emergency and Rescue on Urban Successional Building Fires

Successional building fires in cities may occur both in conventional and unconventional conditions. In the view of emergency response centers, a continuous coordinated work is requested to face (deal with) fires. In general, fires changes dynamically as situation changes, but the effects of sequential characteristic on resource scheduling were seldom considered by existing studies. The effect of fire importance on decision-making, meanwhile, was neglected in most studies. In this work, based on the whole firefighting dynamic process of fire rescue decision environment, we come out with a sequential decision making method. This method introduces the importance of different successional fires and establishes a sequential decision-making model for successional building fires with multi-rescue sources. The objective function of this method is to minimize the burned area. Case studies demonstrate the methodology and its application in fire sequential decision-making with 5 successional fires in Nanchang city. The results indicate that our method can solve problems finding sequential characteristic of successional fires and importance on decision-making.

Current animal models of anxiety, anxiety disorders, and anxiolytic drugs

The perception that 'classical' anxiety tests are deficient was formulated in the mid-1990s. Recent clinical trials also demonstrate that the predictive power of such tests is low, which emphasizes the need for developing models of higher translational value. Several novel models are proposed each year. Here, we investigate their impact on anxiolytic-related studies performed in 2010 and 2011. Here, we depict as 'classical' all the tests that were developed at the same time as or earlier than the elevated plus-maze test. No test equaled its success in the subsequent decades; therefore, we consider it the endpoint of the period when the methodological bases of current laboratory research were laid down. Fourteen classical tests were employed in the investigated period, which were used in more than 80% of studies. Concurrently, 36 'nonclassical' tests were used and six novel tests were also proposed. These accounted for fewer than 20% of studies. 'Classical' tests were often performed under unconventional conditions that putatively increased their translational value. Taken together, half of the studies involved at least one innovative step. Yet, the new procedures were infrequently used. Out of the 36 'nonclassical' tests, only 11 were used more than once, while the amendments to 'classical tests' were almost entirely laboratory specific. Our analysis shows that there is a large interest in performing anxiety research innovatively. However, efforts are highly divergent and result in large numbers of poorly validated and infrequently used novel approaches. Thus, models with increased translational value still need to be developed.

Vibration Suppression of Symmetric Cross-Ply Laminated Composite Beam

A procedure using the dynamic Green's functions was proposed to suppress the transverse vibration of a symmetric cross-ply laminated composite beam excited by an external harmonic force. This was achieved by attaching a set of properly chosen masses and/or translational and rotational grounded springs at arbitrary selected locations along the beam. A scheme was proposed for choosing the optimal values of the added masses and the stiffness of the springs and their locations along the beam to confine the vibration in a certain chosen region. Beams with different boundary conditions, such as pinned-pinned, fixed-fixed, cantilever, free-free, simply-clamped, and simply-free beams, are considered. Other unconventional boundary conditions can be treated as well.

New tagged naplephos ligands for asymmetric allylic substitutions under traditional and unconventional conditions

This paper demonstrates the versatility of the class of chiral ligands naplephos, which has been further refined by preparing new ‘tagged’ versions for selective use in polar media (e.g., ionic liquids). These modified types, along with the best performing original varieties, have been examined in two Pd-catalysed asymmetric processes involving C–C and C–N bond formation. High ees have been achieved in traditional solvents, while the experiments performed in ionic liquids confirm the difficulty of predicting the outcome of a reaction in these media and the general decrease in the catalytic performance.

Texture evolution in Fe–3% Si steel treated under unconventional annealing conditions

The present work investigates texture evolution stages in grain-oriented steel heat-treated using unconventional conditions. The Fe–3%Si steel taken after final cold rolling reduction from an industrial line was subjected to a laboratory isothermal annealing at different temperatures. The annealing temperatures were varied in a range of 850–1150 °C. During the annealing each specimen was heated at 10 °C/s and kept at the stated temperature for 5 min. Development of microstructure and texture in the annealed specimens were followed by the DC measurements of magnetic properties. The grain oriented steel, taken from the same industrial line after final box annealing was also analyzed and compared with the laboratory annealed specimens. It was shown that there is an optimal temperature region that, with combination of a fast heating rate, led to the best conditions of a drastically reduced development time of the {110} < 001 > crystallographic texture in the cold rolled grain-oriented steel. Materials heat treated below the optimum temperature region account for a primary recrystallization, while applying heat above this region leads to a secondary recrystallization without abnormal grain growth. Moreover, in the optimum temperature range, there was a particular temperature leading to the most optimal microstructure and texture. The magnetic properties, measured after the optimal heat treatment, were close to that measured on specimens taken after the final box annealing. The electron back scattered diffraction measurement technique revealed that sharpness of the {110} < 001 > crystallographic texture, developed at the optimum temperature is comparable to the steel taken after the industrial final box annealing. This fact is evidence that there is a temperature where the abnormal grain growth proceeds optimally.

Effect of unconventional curing conditions and storage on pellets coated with Aquacoat ECD

Purpose: Purpose of this study was to develop storage stable pellets coated with the aqueous ethylcellulose dispersion Aquacoat ECD. Methods: The influence of accelerated curing/storage conditions on the release behavior of Aquacoat/HPMC-coated drug pellets were investigated as a function of various formulations (sealing, plasticizer content, and pore-former type/amount) and process parameters (process humidity, thermal curing, and organic processing). Results: Conventionally cured Aquacoat/hydroxypropyl methylcellulose-coated pellets were storage stable at ambient conditions and 25°C/60% relative humidity (RH) but showed a decreasing drug release at 40°C/75% RH, which is a required test condition according to ICH guidelines. Conclusion: Only organic processing of dried Aquacoat or unconventionally harsh curing conditions (60°C/75% RH or 80°C) improved the storage stability of Aquacoat-coated pellets at accelerated conditions.

Effect of unconventional curing conditions and storage on pellets coated with Aquacoat ECD

Effect of unconventional curing conditions and storage on pellets coated with Aquacoat ECD

Stratum ventilation – A potential solution to elevated indoor temperatures

There is worldwide plea to reduce carbon dioxide emission. In response to such a call, several governments in East Asia recently have required to adopt higher room temperatures in summer. To promote such an idea, the public need to be convinced that such practice would not sacrifice indoor environmental quality, especially thermal comfort of the occupants. To implement such a measure, suitable ventilation system(s) to work under the unconventional conditions should be identified. Stratum ventilation is introduced to demonstrate its feasibility in coping for the unconventional warm condition. A case study, a typical office in Hong Kong under local thermal and boundary conditions, is used to illustrate the performance of this new ventilation mode. Computational results show that under the warm condition, with properly designed supplied air velocity and volume, locations of supply and exhaust, the proposed system has the potential to maintain better thermal comfort with a smaller temperature difference between the head and foot level, lower energy consumption, and better indoor air quality (IAQ) in the breathing zone. Much further work is needed to determine if the benefits are significant.

Investigating protein unfolding kinetics by pulse proteolysis

Investigation of protein unfolding kinetics of proteins in crude samples may provide many exciting opportunities to study protein energetics under unconventional conditions. As an effort to develop a method with this capability, we employed "pulse proteolysis" to investigate protein unfolding kinetics. Pulse proteolysis has been shown to be an effective and facile method to determine global stability of proteins by exploiting the difference in proteolytic susceptibilities between folded and unfolded proteins. Electrophoretic separation after proteolysis allows monitoring protein unfolding without protein purification. We employed pulse proteolysis to determine unfolding kinetics of E. coli maltose binding protein (MBP) and E. coli ribonuclease H (RNase H). The unfolding kinetic constants determined by pulse proteolysis are in good agreement with those determined by circular dichroism. We then determined an unfolding kinetic constant of overexpressed MBP in a cell lysate. An accurate unfolding kinetic constant was successfully determined with the unpurified MBP. Also, we investigated the effect of ligand binding on unfolding kinetics of MBP using pulse proteolysis. On the basis of a kinetic model for unfolding of MBP*maltose complex, we have determined the dissociation equilibrium constant (K(d)) of the complex from unfolding kinetic constants, which is also in good agreement with known K(d) values of the complex. These results clearly demonstrate the feasibility and the accuracy of pulse proteolysis as a quantitative probe to investigate protein unfolding kinetics.

Particle imaging of ignition and devolatilization of pulverized coal during oxy-fuel combustion

Oxy-fuel combustion of coal is a promising technology for cost-effective power production with carbon capture and sequestration that has ancillary benefits of emission reductions and lower flue gas cleanup costs. To fully understand the results of pilot-scale tests of oxy-fuel combustion and to accurately predict scale-up performance through CFD modeling, fundamental data are needed concerning coal and coal char combustion properties under these unconventional conditions. In the work reported here, the ignition and devolatilization characteristics of both a high-volatile bituminous coal and a Powder River Basin subbituminous coal were analyzed in detail through single-particle imaging at a gas temperature of 1700 K over a range of 12–36 vol % O 2 in both N 2 and CO 2 diluent gases. The bituminous coal images show large, hot soot cloud radiation whose size and shape vary with oxygen concentration and, to a lesser extent, with the use of N 2 versus CO 2 diluent gas. Subbituminous coal images show cooler, smaller emission signals during devolatilization that have the same characteristic size as the coal particles introduced into the flow (nominally 100 μm). The measurements also demonstrate that the use of CO 2 diluent retards the onset of ignition and increases the duration of devolatilization, once initiated. For a given diluent gas, a higher oxygen concentration yields shorter ignition delay and devolatilization times. The effect of CO 2 on coal particle ignition is explained by its higher molar specific heat and its tendency to reduce the local radical pool. The effect of O 2 on coal particle ignition results from its effect on the local mixture reactivity. CO 2 decreases the rate of devolatilization because of the lower mass diffusivity of volatiles in CO 2 mixtures, whereas higher O 2 concentrations increase the mass flux of oxygen to the volatiles flame and thereby increase the rate of devolatilization.

CHROMATOGRAPHY IN THE EXTREME

RETURN TO ISSUEPREVNewsNEXTCHROMATOGRAPHY IN THE EXTREMESmaller particles, higher pressures, and other unconventional conditions SPUR SPEED AND EFFICIENCY in separationsMITCH JACOBYView Author Information C&EN CHICAGOCite this: Chem. Eng. News 2008, 86, 17, 17–23Publication Date (Print):April 28, 2008Publication History Published online14 November 2010Published inissue 28 April 2008https://doi.org/10.1021/cen-v086n017.p017Copyright © 2008 AMERICAN CHEMICAL SOCIETYArticle Views15Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (3 MB) SUBJECTS:Chromatography,High-performance liquid chromatography,Industrial manufacturing,Mixtures,Pharmaceuticals Get e-Alerts

A Summary of Genetic Classification Using Dynamic Models of Hydrocarbon Reservoirs

Hydrocarbon reservoirs can be divided into 3 groups and 8 sub-groups. The 8 sub-groups include hydrocarbon reservoirs caused by: (i) high pressure potential fields; (ii) low pressure potential fields; (iii) release of dissolved gas from oil and water; (iv) buoyancy; (v) capillary pressure; (vi) deep-basin gas accumulations; (vii) coal-bed methane accumulations formed by molecular adsorption; and (viii) hydrate formation. The 8 sub-groups can be more broadly combined into 3 groups: (1) hydrocarbon reservoirs resulted from episodic fluid pressure, which include sub-groups (i) and (ii); (2) hydrocarbon reservoirs caused by steady and continuous hydrocarbon potential difference, including sub-groups (iii)-(v); (3) hydrocarbon reservoirs formed under unconventional conditions, which are represented by sub-groups (vi)-(viii). Hydrocarbon reservoirs with the same dynamic origin can be further subdivided into groups according to their geological settings. With different dynamic origins, various hydrocarbon reservoirs have different distribution patterns and major controlling factors. In order to enhance oil and gas field exploration and increase exploration probabilities of success, it is both important and necessary to study the dynamic mechanisms and associated genetic models for hydrocarbon migration and accumulation.

Design and Constitutional Features of Mesophase-Forming Uni- or Supramolecular Discotic Materials [1,2

After introductory comments on the situation of liquid crystal work and its importance in scientific, technological, and social respect before the discovery and start of systematic exploration of non-linear, flat, i.e., disc-shaped mesogens twenty-five years ago, illustrative thermotropic liquid crystalline uni- or supramolecular discotics are discussed in relation to geometric features of their constituent molecules or aggregates. These materials are divided into two main groups: radial-symmetric disc-like and unconventional non-linear mesogens. The first main group deals, first of all, with representative standard and thereafter with organometallic mesogens, whereas the second one is sub-divided into four parts: bulky unimolecular mesogens; hydrogen bonding and molecular recognition; polycatenar types of mesogens; inter- and intramolecular EDA/CT complexes. Clearly, the significance of micro-segregation for the mesophase formation in cases of unconventional molecular conditions is emphasized as well.

Features of the simplest model of second-harmonic magneto-optical Kerr effects

A generalised formalism of characteristic matrices is presented to analyse second-harmonic magneto-optical Kerr effects in an optically anisotropic centrosymmetric ferromagnetically ordered multilayer if its response can be described in terms of electric polarisation. Features of the model associated with ideal (infinitely thin) interfaces are highlighted. These are due to both the existence of two versions of unconventional boundary conditions and an inevitable conventional approach to defining the surface polarisations through the fundamental electric field and surface-susceptibility tensors. New analytical results for linear and second-harmonic Kerr effects are shown to be advantageous for developing an effective algorithm for their numerical simulation. The linear approximation with respect to magnetisation is pursued, thereby also making our results suitable for investigating a great variety of magneto-optical effects and (in the second-harmonic case) effects related to anisotropy.

Consequences of catalyst deactivation for process design and operation

Catalyst deactivation has important consequences for the design of a process and the way it is operated. The nature of the deactivation, and in particular the question whether it can be reversed under conditions which are compatible with the normal operation or whether a separate regeneration treatment of the catalyst is required to restore its activity, as well as the time-scale of the deactivation determine the type of technology that is feasible and process options like reactor type and process configuration. This relationship between deactivation behaviour and process lay-out forms the subject matter of the present paper. The general principles that guide the choices of process type and parameters are illustrated in more detail with examples from the fields of catalytic reforming of petroleum naphtha and hydroprocessing of petroleum residues. In these fields, different catalyst deactivation mechanisms are operative and catalyst deactivation rates can vary widely depending upon feedstock and process parameters. Consequently, different reactor technologies and process configurational choices are possible. The relation between catalyst deactivation behaviour and process design and operation can be viewed from two sides: on the one hand, the deactivation behaviour may dictate the choice between viable process options and may provide an incentive for the development of novel technology that can cope optimally with the demands set by the deactivation of the catalyst. On the other hand, the introduction of novel technological options may widen the scope of a process, e.g. by opening the possibilities to apply novel catalysts or to operate under unconventional conditions that lead to a more economic or otherwise better process, possibilities that were previously barred by catalyst deactivation.