Unit Clauses Research Articles

Process simulation, optimization, and cost analysis of a proposed sulfur recovery unit by applying modified Claus technology

Removing sour gas from any suitable gas sweetening technology in a cost-effective and environmentally responsible manner is a major challenge. This paper discusses how to safely and economically dispose of small amounts of acid gases resulting from the amine sweetening process. A two-stage Claus desulfurization unit was studied and simulated to treat acid gases resulting from natural gas sweetening operations in Ras Gharib oil fields (Egypt). These acid gases are used as feedstock for the proposed plant to produce a valuable product, such as elemental sulfur, which is used as a raw material in many industries. Although many sulfur recovery techniques are available for various conditions and applications, the Claus process is a critical and widely used method for recovering elemental sulfur from gaseous hydrogen sulfide. This work represents the potential benefits of treating acid gases with high hydrogen sulfide content. In addition, operational variables that could affect sulfur production and sulfur recovery efficiency of the studied Claus unit were studied and optimized. Aspen HYSYS simulation software (version 9) was used to evaluate the economic aspects and optimize the operational parameters of the unit for producing sulfur from acid background gases. The results showed that the maximum sulfur production was achieved at a catalytic converter reactor temperature of 270 °C and 210 °C for the first and second catalytic reactor, respectively, with an air flow rate of 933.3 kg mol/h. The economic study of the proposed desulfurization unit showed that the Claus unit would be economically acceptable with an expected return on investment of approximately 10% and an average payback period of 10 years. Moreover, the introduced plant has a positive impact on the environment by reducing the concentration of hydrogen sulfide in the gas from 69.58 to 0.16%.

Rapid Hydrate Formation Conditions Prediction in Acid Gas Streams

Sour gas in hydrocarbon reservoirs contains significant amounts of H2S and smaller amounts of CO2. To minimize operational costs, meet air emission standards and increase oil recovery, operators revert to acid gas (re-)injection into the reservoir rather than treating H2S in Claus units. This process requires the pressurization of the acid gas, which, when combined with low-temperature conditions prevailing in subsurface pipelines, often leads to the formation of hydrates that can potentially block the fluid flow. Therefore, hydrates formation must be checked at each pipeline segment and for each timestep during a flow simulation, for any varying composition, pressure and temperature, leading to millions of calculations that become more intense when transience is considered. Such calculations are time-consuming as they incorporate the van der Walls–Platteeuw and Langmuir adsorption theory, combined with complex EoS models to account for the polarity of the fluid phases (water, inhibitors). The formation pressure is obtained by solving an iterative multiphase equilibrium problem, which takes a considerable amount of CPU time only to provide a binary answer (hydrates/no hydrates). To accelerate such calculations, a set of classifiers is developed to answer whether the prevailing conditions lie to the left (hydrates) or the right-hand (no hydrates) side of the P-T phase envelope. Results are provided in a fast, direct, non-iterative way, for any possible conditions. A set of hydrate formation “yes/no” points, generated offline using conventional approaches, are utilized for the classifier’s training. The model is applicable to any acid gas flow problem and for any prevailing conditions to eliminate the CPU time of multiphase equilibrium calculations.

A Machine Learning-Based Method for Modelling a Proprietary SO2 Removal System in the Oil and Gas Sector

The aim of this study is to develop a model for a proprietary SO2 removal technology by using machine learning techniques and, more specifically, by exploiting the potentialities of artificial neural networks (ANNs). This technology is employed at the Eni oil and gas treatment plant in southern Italy. The amine circulating in this unit, that allows for a reduction in the SO2 concentration in the flue gases and to be compliant with the required specifications, is a proprietary solvent; thus, its composition is not publicly available. This has led to the idea of developing a machine learning (ML) algorithm for the unit description, with the objective of becoming independent from the licensor and more flexible in unit modelling. The model was developed in MatLab® by implementing ANNs and the aim was to predict three targets, namely the flow rate of SO2 that goes to the Claus unit, the emissions of SO2, and the flow rate of steam sent to the regenerator reboiler. These represent, respectively, the two physical outputs of the unit and a proxy variable of the amine quality. Three different models were developed, one for each target, that employed the Levenberg–Marquardt optimization algorithm. In addition, the ANN topology was optimized case by case. From the analysis of the results, it emerged that with a purely data-driven technique, the targets can be predicted with good accuracy. Therefore, this model can be employed to better manage the SO2 removal system, since it allows for the definition of an optimal control strategy and the maximization of the plant’s productivity by not exceeding the process constraints.

Handling All Unit Propagation Reasons in Exact Max-SAT Solvers

Unit propagation (UP) based method are widely used in Branch and Bound (BnB) Max-SAT solvers for detecting disjoint inconsistent subsets (IS) during the lower bound (LB) estimation. UP consists in assigning to true (propagating) all the literals which appear in unit clauses. The existing implementations of UP only consider the first unit clause causing the assignment of each variable, thus the propagations must be done and undone chronologically to ensure that all the unit clauses are properly exploited. Max-SAT BnB solvers transforms the formulas to ensure IS disjointness. These transformations remove clauses from the formula thus propagations are frequently undone. Since the propagations are undone in chronological order, many useless unassignments and reassignments are performed. We propose in this paper a new unit propagation scheme which considers all the unit clauses causing the assignment of the variables by UP. This new scheme allows to undo propagations in a non-chronological way and thus it reduces the number of redundant propagation steps made by BnB solvers. We also show how the information available with this new scheme can be used to influence the characteristics of the IS built by BnB solvers. We propose a heuristic which aims at reducing their size, and thus improving the quality of the LB estimation. We have implemented the new propagation scheme as well as the IS building heuristic in our solver MSsolver. We present and discuss the results of the experimental study we have performed.

Multi-verb constructions in Eastern Indonesia by Volker Unterladstetter

Reviewed by: Multi-verb constructions in Eastern Indonesia by Volker Unterladstetter Leah Pappas Volker Unterladstetter. 2020. Multi-verb constructions in Eastern Indonesia. Studies in Diversity Linguistics 28. Berlin: Language Science Press. 452 pp. ISBN 978-3-96110-216-7, digital. ISBN 978-3-96110-217-4, hardcover. Open Access. Multi-verb constructions (MVCs) have recently received attention in the literature on multi-verb strings. While some authors such as Nordhoff (2012) find value in keeping the term broad and descriptive, others such as Aikhenvald (2011) and Enfield (2008) seek to specify parameters that define MVCs. Despite the variation in these approaches, usually authors minimally identify MVCs to be verb strings within a single clause with an absence of linking elements between the verbs. MVC has become a popular term because traditionally much of the discussion around multi-verb strings has centered on the more theoretically entrenched term "serial verb construction" (SVC). Issues with the term "SVC" arise when one tries to define what constitutes an SVC; authors tend to vary as to whether to include a broad set of defining parameters or a narrow set of easily identifiable universals (Haspelmath 2016). However, based on the parameters that authors most-commonly adopt, SVCs are viewed as equally inflected verb strings within a single clause and intonation unit that show no signs of coordination, syntactic dependency, nor subordination. Yet, these parameters can sometimes be restrictive and are not always typologically applicable. Thus, the term MVC has been adopted into the serial verb literature by authors who wish to avoid extensive theoretical debates in their grammatical descriptions or by those who seek to include constructions that are clearly not SVCs in their analysis. For the time being, "multi-verb construction" remains a hyperonymic and manipulatable term to describe verb strings. The book under review provides a comprehensive overview of the semantic, syntactic, and areal features of MVCs in Eastern Indonesia (EI) based on data from sixteen Austronesian and sixteen non-Austronesian languages. Using several types of data—corpus data, published grammars, and glossed texts—the author grapples with a variety of analytical frameworks employed by different authors. In order to objectively approach this data and account for the immense grammatical diversity in EI languages, Unterladstetter adopts the term MVC. As a result, he is able to include a broad corpus of multi-verb strings which is not constrained by what one may define as "canonical" serial verb constructions. The resulting approach to typologizing MVCs systematizes the interplay between their syntactic and semantic parameters and has the potential for widespread applicability to MVCs anywhere in the world. The book provides several novel contributions including the idea of hierarchized MVCs, the [End Page 243] adoption of Davidsonian semantics and lexical decomposition in the MVC context, and a systematic approach to event analysis in language. This book consists of seven chapters. It begins with a general introduction (chapter 1), followed by more specific introductions to the languages of EI (chapter 2) and the literature around SVCs and MVCs (chapter 3). These reviews are followed by a description of the grammatical (chapter 4) and semantic (chapter 5) properties of MVCs in EI which are then combined to describe the various types of MVC constructions in the region (chapter 6). Finally, Unterladstetter concludes with a discussion that summarizes the contents of the book and identifies its broader implications and avenues for future research (chapter 7). Chapter 1 establishes the scope of the book and provides the background information necessary for any reader to understand the content. This chapter further introduces the broad goals of the book while briefly summarizing the material addressed in chapters 2 and 3. In addition to laying out the hypotheses that are investigated throughout the book (repeated below), Unterladstetter preliminarily defends his position to address MVCs rather than SVCs. All topics in chapter 1 are addressed in more detail in the following chapters. In chapter 1 (p. 15), the author identifies the following to be the primary hypotheses explored throughout the book: 1. Although the morphosyntactic make-up of MVCs in EI is remarkably similar across different construction types, these MVCs are constructed through different techniques (mentioned below in #H2) 2. Verbal interaction in...

Lifting propositional proof compression algorithms to first-order logic

Abstract Proofs are a key feature of modern propositional and first-order theorem provers. Proofs generated by such tools serve as explanations for unsatisfiability of statements. However, these explanations are complicated by proofs which are not necessarily as concise as possible. There are a wide variety of compression techniques for propositional resolution proofs but fewer compression techniques for first-order resolution proofs generated by automated theorem provers. This paper describes an approach to compressing first-order logic proofs based on lifting proof compression ideas used in propositional logic to first-order logic. The first approach lifted from propositional logic delays resolution with unit clauses, which are clauses that have a single literal. The second approach is partial regularization, which removes an inference $\eta $ when it is redundant in the sense that its pivot literal already occurs as the pivot of another inference in every path from $\eta $ to the root of the proof. This paper describes the generalization of the algorithms LowerUnits and RecyclePivotsWithIntersection (Fontaine et al.. Compression of propositional resolution proofs via partial regularization. In Automated Deduction—CADE-23—23rd International Conference on Automated Deduction, Wroclaw, Poland, July 31–August 5, 2011, p. 237--251. Springer, 2011) from propositional logic to first-order logic. The generalized algorithms compresses resolution proofs containing resolution and factoring inferences with unification. An empirical evaluation of these approaches is included.

Understanding the power of Max-SAT resolution through UP-resilience

A typical Branch and Bound algorithm for Max-SAT computes the lower bound by estimating the number of disjoint Inconsistent Subsets (IS) of the formula. The IS detection is ensured by Simulated Unit Propagation (SUP). Then, the inference rule for Max-SAT, Max-SAT resolution, is applied to ensure that the detected IS is counted only once. Learning Max-SAT resolution transformations can be detrimental to the algorithm performance, so they are usually selectively learned if they match certain patterns. In this paper, we study the impact of the transformations by Max-SAT resolution on the SUP mechanism, indispensable for IS detection. We introduce the notion of UP-resilience of a transformation which quantifies this impact and provides, from a theoretical point of view, an explanation to the empirical efficiency of the learning schemes developed in the last ten years. We also focus on recently introduced patterns called Unit Clause Subsets (UCSs). We characterize the transformations of certain UCSs using UP-resilience and we explain how our result can help extend the current patterns. Finally, we present empirical observations that support the relevance of the UP-resilience property and further consolidate our theoretical results.

Old techniques in new ways: Clause weighting, unit propagation and hybridization for maximum satisfiability

Maximum Satisfiability (MaxSAT) is a basic and important constraint optimization problem. When dealing with both hard and soft constraints, the MaxSAT problem is referred to as Partial MaxSAT, which has been used to effectively solve many combinatorial optimization problems in real world. The local search method and the SAT-based method are two popular methods for Partial MaxSAT. Nevertheless, local search algorithms have been dominated by SAT-based algorithms on industrial benchmarks. This work develops an effective local search algorithm for industrial benchmarks, which for the first time is competitive with SAT-based algorithms on industrial MaxSAT benchmarks.We propose a local search algorithm, called SATLike, which exploits the structure of Partial MaxSAT by a novel clause weighting scheme. Then we improve SATLike by integrating a unit propagation based decimation algorithm to generate initial solutions, leading to an improved algorithm, called SATLike 2.0. We also refine SATLike 2.0 and obtain SATLike 3.0. Furthermore, we apply SATLike 3.0 to improve two SAT-based solvers, leading to two hybrid MaxSAT solvers that push the state of the art in MaxSAT solving.Experiments on benchmarks from the MaxSAT Evaluations 2017 and 2018 show that SATLike significantly outperforms previous local search solvers on all the benchmarks. More importantly, SATLike 3.0 has better performance than state-of-the-art SAT-based solvers on unweighted industrial benchmarks. The two hybridized solvers obtain significant improvements on both unweighted and weighted benchmarks.

Interpersonal meaning breadth variation in simultaneous interpreting English – bahasa Indonesia dienic texts: A contrastive-translational mood grammar analysis

This study presents a contrastive-translational MOOD grammar analysis of the realization of interpersonal meaning in Joyce Meyer’s English sermon text and Jose Carol’s Bahasa Indonesia interpreted text. Interpersonal meaning in the framework of Systemic Functional Linguistics (SFL), the model of Translational Semiotic Communication (TSC) and the model of text type and language function are the theoretical foundations of this study. This study used a descriptive qualitative-quantitative approach, involving the analysis of MOOD and Modality of the data which were translationally related semantic units grammatically expressed by MOOD clause units. The analysis reveals that the texts in this study can be classified as dienic texts with Declaratives and Imperatives as the prominent clauses, while Modality elements realized in T1 were generally realized in T2 in the same types. Declaratives and Imperatives respectively serve the informative and operative function of the texts, and the Modality elements which are mostly of a high degree and expressed explicitly give values to these functions.

Life cycle assessment and techno-economic analysis of biomass-to-hydrogen production with methane tri-reforming

In this study, the techno-economic, energy consumption (EC), and environmental performances of biomass-to-hydrogen (BTH) production with/without methane tri-reforming (MTR) from corn straw were studied. The techno-economic analysis includes an assessment of the energy efficiency, MTR operating conditions, total capital investment (TCI), production cost (PC), and payback period. The BTH energy efficiency with MTR is 17.08% higher than that without MTR. The Claus unit is the largest contribution unit of energy loss. The reaction temperature and operating pressure of one MTR unit are 800 °C and 0.1 MPa, respectively. Compared with BTH without MTR, the TCI of BTH with MTR increased by 10.97%, and the PC decreased by 10.12%. The static payback period of BTH with MTR is approximately 4.72 yr. BTH without MTR exhibits 3.09% less EC and 7.85% greenhouse gas emissions than that of BTH with MTR. The life cycle analysis of the BTH process illustrates that the BTH with MTR can realize negative carbon dioxide (CO2) emissions when considering the natural carbon cycle. The evaluation method combines a thermodynamic analysis with a life cycle assessment, which is significant for the development of clean hydrogen production technology with low carbon and high energy savings.

Modeling of mass transfer and hydrodynamic investigation of H2S removal from molten sulfur using porous Sparger

Empirical and theoretical aspects of non-catalytic molten sulfur degassing as one of the vital actions in Claus Unit have been investigated in this article. A laboratory bubble column has been set up to study the hydrodynamic behavior of gas-liquid system. Values of gas holdup were also compared with predictions of some correlations in the case of application of porous spargers. The mathematical model of degassing was also developed considering reaction of H2S with sulfur molecules in the molten sulfur and generation of H2Sx species. The experimentally-measured parameters of gas holdup and bubble size were used in the mathematical model. Other parameters including Henry’s law constant of H2S-liquid sulfur system and reaction rate constants were obtained from published formulas presented by Marriott and Ji, respectively. The obtained results were compared to the empirical data of non-catalytic degassing performed in the laboratory setup. Reasonable compatibility was observed between the model-derived and experimental results. The results showed a fast removal of dissolved H2S within few minutes, followed by very slow removal of H2Sx through its chemical conversion to H2S and its purging by sweep gas. The novel gas holdup profile and images presented in this article show interesting features of hydrodynamic behavior of molten sulfur.

For a new semiotics in Construction Grammar: A statistical analysis of the relationship between transitive syntax and semantics

AbstractBy extending the notion of constructions beyond “irregular” structures, Goldberg (1995.Constructions: A construction grammar approach to argument structure. Chicago: University of Chicago Press) made possible the analysis of clause units as a global pattern associating syntax to principles for semantic interpretation. Despite this theoretical advance, Construction Grammar’s pairing of syntactic structure and conceptual form reflects Saussure’s signifier/signified semiotic model, which poses some issues. Problems arise when a single formal structure expresses distinct semantic patterns or, conversely, when semantics persists notwithstanding formal variation. In order to approach this unstable syntax/semantics interface, this work proposes a statistical methodology to capture the correlation between syntax and Hopper and Thompson's (1980. Transitivity in grammar and discourse.Language56(2). 251–299) parameters of transitivity. In a corpus of 7,939 clauses from 23 oral interviews, 690 randomly sampled clause units were analyzed using Generalized Estimating Equation. The data suggests that, in Brazilian Portuguese, most of those parameters are not particularly related to the prototypical transitive syntax and might be specified outside the scope of this clausal structure. Nonetheless, Affectedness is a syntax/semantic interface point that is, first, largely independent of lexical items and, second, capable of distinguishing transitive syntax from other clausal patterns. Based on this analysis, we conceive the Transitive Construction as a superordinate rule that acts upon the formal organization of a language, establishing clausal patterns both synchronically and diachronically.

Cognitive Processes on Translation Studies of English Language Learners

There were many studies discussed on the product of translation. Meanwhile, few researcher lazy to watch the process of translation. This paper, therefore, investigated a study on the processes when a translator performed the translation. The cognitive process played an important role in it. The aims of the study are to describe the think aloud protocols as one of the assessment to explore the translation behaviours or strategies in translation and to analyze cognitive processes that occur in the mind of postgraduate students when they did the translation. This research is also necessary to know the difficulties faced by the students when conducting the process of it. The study that involved fifteen participants, resulted to some difficulties, namely in translating lingual word unit, lingual phrase unit, and lingual clause unit. The overcome strategies were refers to a dictionary, knowledge of the subject (guessing), and the attention of local context and content. It is suggested that, although the think-aloud assessment has limitations, but it is an appropriate instrument for looking into the mental process of a translator.

Accelerating MUS enumeration by inconsistency graph partitioning

The problem of finding minimal unsatisfiable subsets (MUSes) has been studied frequently because of itstheoretical importance and wide range of applications in domains such as electronic design automation,software, and integrated circuit verification. In this paper, a method for accelerating theenumeration of MUSes based on inconsistency graph partitioning is proposed. First, an inconsistency graphof a set of clauses is constructed by extracting the inconsistencyrelations between literals of different clauses. In this paper, we show that by partitioning the inconsistency graphinto small connected components through a vertex cut, the enumeration of MUSes in different componentsbecomes independent and it is possible to compute them separately. Moreover, the MUSes of the original clause setcan be constructed by merging the unit clauses in the MUSes of these connected components back into the clauses inthe vertex cut. Experiments show that by integrating the acceleration method into the MARCO MUSes enumerator,there is a 2–3 times improvement in the average runtime of solved instances for randomly generatedbenchmarks. By integrating the acceleration method into itself as an MUS enumerator, there isanother 3–4 times improvement when compared with the accelerated MARCO.

Partial maximum satisfiability problem method combined with structure characteristics for diagnostic problems

Partial MaxSAT (PMS) is a generalized version of the maximum satisfiability problem (MaxSAT), which has important applications in many fields. At present, the PMS algorithm requires improvements in solving the industrial problems. Based on deep research on the PMS algorithm using random search, this paper presents a structure characteristics partial MaxSAT (SCPMS) method that combines structural feature exploration. First, according to the unit propagation rules and structural features of the problem, we gradually divide the PMS clause into two parts to construct a subproblem that can satisfy the problem due to the absence of the hard unit clause. In this paper, a random search guidance strategy is proposed. The new subproblem is reused to identify the hard-blocking variable in the hard unit clause of the original problem using unit propagation. Then, the corresponding soft-blocking variable is reversed with the feature of the clause to improve the efficiency of the random search. The experimental results show that in comparison with the two latest algorithms, DeciDist and DistUp, the proposed SCPMS greatly reduces the number of unsatisfied soft clauses in solving model-based diagnosis instances.

Novel Approach to Sour-Gas Treatment Lowers Cost and Limits Safety Hazards

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 193115, “Novel Approaches to Sour-Gas Treatment in Oil and Gas: Onshore and Offshore Facilities,” by Iain Pollitt and Joao Conde, Infinity Oilfield Services, prepared for the 2018 SPE Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 12–15 November. The paper has not been peer reviewed. This paper investigates novel approaches to sour-gas treatment for use in the Middle East that are outside the common oil and gas market and compares them with traditional techniques. The methods presented in this paper were based on one central tenet: deliver a practical, economical solution to producing from an extremely sour [greater than 40,000-ppm hydrogen sulfide (H2S)] gas field. Modified tail-gas treatment units (TGTUs) were found to be economically viable, can be implemented onsite, and can tie in to existing infrastructure with minimal capital expenditure (CAPEX) or operational expenditure (OPEX). Introduction A field in the Mediterranean was producing sour gas at a rate that would render production untenable. One of the wells was producing 24,000-ppm H2S with an expected increase to 46,000 ppm within a few years. While the lower rate allowed production as long as it was coincident with other, sweeter wells in the region, the rising sourness eventually would render operation impossible. To counter this trend, a stage-gate process was established to identify potential solutions and an array of technologies was proposed. The main criteria that have been considered for the selection of gas-sweetening technologies are cost, operability, and efficiency. The selected options would be analyzed on the basis of these criteria using a screening sheet upon which each criterion had been broken into key elements (the screening method is detailed in Appendix A of the complete paper). The selected option ideally should be low-cost, highly efficient, and environmentally friendly. Offshore Acid-Gas Removal Options These technologies included the following: H2S scavengers Absorption processes Regenerative absorption Nonregenerative absorption Adsorption H2S-removal processes Regenerative adsorption Nonregenerative adsorption Membrane separation The membrane-separation units consist of many polymerized hollow fibers arranged asymmetrically and formed into loose bundles of membrane elements. When a pressure differential is applied, the molecules diffuse into the pores of the polymeric material and transport (permeation) occurs across the membrane. Membrane units have relatively modest layout requirements, and CAPEX can be modest to high. Acid-Gas Disposal-Treatment Options Claus+TGTU. In the Claus process, H2S is treated with air (oxygen) over a catalyst to form elemental sulfur and water. The tail gas from a Claus unit goes through a tail-gas cleanup or TGTU process. Liquid-Redox Process. Processes in this group absorb H2S from gas streams and react oxygen with the H2S to form elemental sulfur and water. Iron-chelate processes belong to the liquid-redox sulfur-recovery group and are the most commonly used active redox reagents. A chelating agent is generally an organic molecule able to bind with a metallic cation in such a way that the cation is sequestered from the solution.

VARIASI KELUASAN MAKNA PENGALAMAN DALAM PENERJEMAHAN NOVEL RONGGENG DUKUH PARUK KE DALAM BAHASA INGGRIS

There is no “real equivalence” in translation; it is always relative, finding the best among the defect possibilities. This study was aimed to discover the the types of variations of the experiential meaning breadth (EMB) in a novel, 'Ronggeng Dukuh Paruk' in Indonesian and English, to find out the EMB variation level.This is a descriptive qualitative endevour, applying a content analysis method, focusing on the experiential meaning, particularly on its breadth dimension. The data sources are two language versions of the novel, Indonesian (Ind) and English (En). The data are clause units of transitivity. The results of this study indicate that the most dominant EMB variation is 0 variation. The intertextual bond is proved to be strong in leading the translators to create the meaning of the clauses. In general the variation level of EMB is very low, 9.16. This indicates that the intertextual context plays a very dominant role to lead the decision of the translator in realizing the meaning. The variations in the EMB in general do not affect the completeness of the meaning.

The Effects of Intervention of Using Clause Units on the Improvement of Specific Language Impairments (SLI) in Childrens’ Embedded Sentences

The Effects of Intervention of Using Clause Units on the Improvement of Specific Language Impairments (SLI) in Childrens’ Embedded Sentences

Conceptual design and analysis of a novel system based on ash agglomerating fluidized bed gasification for co-production of hydrogen and electricity

In this paper, a novel system with ash agglomerating fluidized bed gasification and CO2 capture to produce hydrogen and electricity is firstly designed in Aspen Plus. The newly-proposed system is composed of eight subsystems, namely air separation unit, gasification unit, water gas shift unit, Rectisol unit, CO2 compression unit, Claus unit, pressure swing adsorption unit, gas and steam turbine unit. The thermodynamic performance and hydrogen to coal ratio of the new proposed system are investigated. The results demonstrate that the hydrogen to coal ratio, energy efficiency, net electricity power and exergy efficiency of the overall system for Yangcheng anthracite are 0.096 kg/kg, 46.52%, 1.71 MW and 43.92%, respectively. Additionally, the exergy destruction ratio and exergy efficiency of each subsystem are researched. More importantly, the influences of the oxygen to coal ratio, steam to coal ratio and coal types on the hydrogen to coal ratio, energy efficiency and exergy efficiency are also studied.

Pauses Reflecting the Processing of Syntactic Units in Monolingual Text Production and Translation

This study explores how the process of translating relates to other types of writing processes by comparing pause lengths preceding syntactic units (words, phrases and clauses) in two types of writing task, a monolingual text production and a translation. It also discusses the grounds for interpreting pause length as a reflection of the cognitive demands of the writing process. The data was collected from 18 professional translators using the Translog keystroke logging software (Jakobsen/Schou 1999). Each subject wrote two texts: an expository text in Finnish and a translation from English into Finnish (Immonen 2006: 316-319). Firstly, phrase boundary pauses were categorised according to type, function and length of phrase. All three features correlate with pause length. On average, predicate phrases are preceded by short pauses, adpositional phrases by long pauses, and pauses preceding noun phrases grow with the length of the phrase. These fi ndings suggest that the processing of the predicate begins before written production of the clause is started, whereas noun phrases and adpositional phrases are processed during writing. Secondly, pauses preceding clauses were categorised with respect to clause type. In monolingual text production, pauses preceding subordinate clauses are on average shorter than those leading to main clauses. In translation, pauses preceding subordinate and main clauses are almost the same length. It seems therefore that, in translation, the main clause and subordinate clause are processed separately despite the fact that the subordinate clause functions as a syntactic unit within the main clause.