Modeling Biomass Gasification: A New Approach to Utilize Renewable Sources of Energy

2008 ◽  
Author(s):  
M. Vaezi ◽  
M. Passandideh-Fard ◽  
M. Moghiman ◽  
M. Charmchi
Keyword(s):  
Selection Procedure ◽  
Calorific Value ◽  
Gas Temperature ◽  
New Approach ◽  
Wide Range ◽  
Specific Biomass ◽  
Thermochemical Equilibrium ◽  
Biomass Materials ◽  
Gasification Efficiency ◽  
Selection Of

Thermochemical equilibrium modeling is the basis of the numerical method implemented in this study to predict the performance of a biomass gasifier. To validate the model, a close agreement is shown between numerical and experimental results. The model is then used in order to optimize the selection procedure of a specific biomass for a certain application. For this purpose, the minimum and maximum amount of carbon, hydrogen, and oxygen for 55 different biomass materials are extracted to calculate the range of variation of oxygen content and carbon/hydrogen ratio. The influences of such variations on syngas characteristics are then studied. Syngas characteristics are comprised of syngas calorific value, outlet gas temperature, gasification efficiency, and the volume of syngas obtained. The results are plotted in a generalized format that may be used for a wide range of biomass materials. These plots can be used for the selection of a biomass material based on desired conditions. Therefore, the developed model in this study provides a tool for design optimization of a biomass downdraft gasifier.

A Multi Fuelled Cyclone Combustor

1992 ◽  
Vol 3 (4) ◽  
pp. 401-416
Author(s):  
T. O'Doherty ◽  
D.J. Morgan ◽  
N. Syred
Keyword(s):  
Coal Ash ◽  
Calorific Value ◽  
Particulate Emissions ◽  
Particulate Emission ◽  
Exhaust Gases ◽  
Cyclone Combustor ◽  
Wide Range ◽  
Chicken Litter ◽  
Biomass Materials ◽  
Secondary Air

The paper outlines a series of tests carried out on a prototype 1.5 MW vertical cyclone combustor with integral ash removal which removes in excess of 80% of the ash. For high calorific value fuels such as coal the system is run fuel rich to avoid slagging. The low calorific value exhaust gases are passed via a transfer duct into an inverted swirl burner/furnace arrangement where final burnout of the gasified products occur. The sytem, designed to utilise a wide range of solid fuels was evaluated for a range of biomass materials and coal. The coal work investigated the effects of crushed (dm ≃ 250 μm) and pulverised (dm ≃ 70–80 μm) bituminous coals on system performance whilst biomass trials investigated the effects of chopped straw, chicken litter, shredded paper and refuse derived fuels. The fuel and air were premixed and fired tangentially in all cases into the primary combustor. The combustor was operated over a range of mixture ratios (φ) from fuel rich (φ = 0.5) to fuel lean (φ = 2.0) with temperatures in the order of 1250°C, hence operated in a non-slagging mode. The whole system was operated with a minimum of secondary air, required only to burn the gasified products from the primary chamber. The trials included monitoring of exhaust gases for a range of emissions. In addition, isokinetic sampling of the exhaust gases was carried out to determine particulate emission levels. Results show that best fuel burnout is achieved with biomass material levels better than 99% being achieved. Satisfactory performance was achieved with coal, (ash retention emissions) with fuel burnout in the order of 80%. Ash retention values for the biomass materials was in excess of 80% up to 98%. Coal ash retention levels were lower when analysed on a mass balance basis but of the same order when considering particulate emissions.

Publishing patterns in Pharmacy

2021 ◽  
Vol 2 (2) ◽  
pp. 65-91
Author(s):  
Terhi Sandgren
Keyword(s):  
Pharmaceutical Preparations ◽  
Research Field ◽  
Multiple Perspectives ◽  
Research Information ◽  
New Approach ◽  
Wide Range ◽  
Comprehensive Picture ◽  
Using Data ◽  
National Languages ◽  
Selection Of

Pharmacy is a multidisciplinary research field that combines natural sciences, health sciences and social sciences to study drugs and pharmaceutical preparations from multiple perspectives. The study explores publishing patterns in pharmacy via bibliometric methods, that is statistical methods applied to study scientific literature. Earlier bibliometric studies focusing on pharmacy have used data from the international citation databases Web of Science and Scopus. In most of these studies, pharmacy has been operationalized by focusing on journals categorized as pharmacy journals. This study provides a new approach to the study of publishing patterns, by using data from institutional Current Research Information Systems (CRIS), and by using pharmacy organizations as the basis of operationalization of pharmacy. It seeks to provide a more comprehensive picture of publishing patterns, since the data covers all publication types used in pharmacy and is not limited to pharmacy journals. The objective of this study is thus to explore whether the selection of databases and operationalization of the discipline affects the results concerning publishing patterns in pharmacy.  The results obtained in this study are very similar to earlier studies utilizing international databases. However, the results show that pharmacy researchers also publish in national languages, and that there are several national journals amongst the core journals that are not covered by the international databases. The multidisciplinary nature of pharmacy can be seen in the wide range of journals in which pharmacy researchers publish their articles.

Selection of dairy sheep in Greece for parasitic nematode resistance: defining the aggregate genotype and evaluating selection schemes

1999 ◽  
Vol 69 (3) ◽  
pp. 535-542 ◽  
Author(s):  
A. Kominakis ◽  
G. Theodoropoulos
Keyword(s):  
Genetic Gain ◽  
Milk Fat ◽  
Genetic Correlations ◽  
Selection Procedure ◽  
Nematode Resistance ◽  
Repeated Measurements ◽  
Production Traits ◽  
Dairy Sheep ◽  
Wide Range ◽  
Selection Of

AbstractThe effects on genetic and economic responses of adding faecal egg count (FEC) in the aggregate genotype of dairy sheep in Greece were investigated. The extra responses obtained in the full aggregate genotype were expressed as a percentage change of the responses in terms of genetic gain, profit and selection response of single traits before adding the trait. The initial aggregate genotype included the traits milk fat yield (FY) and number of lambs weaned per ewe per year (NLW). Inclusion of FEC in the aggregate genotype resulted always in increased genetic gain and profit. The extra responses from adding the FEC in the index selection were variable and often very large, depending on the parameters varied i.e. the economic weight of FEC and the genetic correlation of FEC with the other production traits. For a wide range in the size of the genetic correlations between FEC and other traits, gains of FEC and no appreciable losses of responses for FY and NLW were predicted when FEC accounted proportionately for 0·10 to 0·20 of the total monetary genetic deviation. While FEC showed a wide range of change, selection responses of FY and NLW remained remarkably insensitive under various weightings of FEC and different genetic correlations of FEC with the production traits. The genetic and economic efficiency of alternative selection schemes were also evaluated. A two-stage selection procedure involving preliminary selection of rams on dam’s FEC, FY, NLW and on their own FEC and final culling on progeny’s FEC, FY and NLW was predicted to be the most efficient in both genetic and economic terms. Female replacements should be selected on dam’s FEC, FY and NLW (first stage) and their own FEC, FY and NLW (second stage). When repeated measurements of FEC are taken, the recommended number of FEC measurements was found to be 4.

Selection criteria for slurry trench cutoffs

1983 ◽  
Vol 10 (3) ◽  
pp. 527-537
Author(s):  
M. D. Haug ◽  
Paul Kozicki
Keyword(s):  
Selection Process ◽  
Selection Procedure ◽  
Poor Performance ◽  
Engineering Properties ◽  
Cutoff Wall ◽  
Factors Affecting ◽  
Wide Range ◽  
Slurry Trench ◽  
Open Trench ◽  
Selection Of

Slurry trench cutoff walls have been employed for over three decades and are becoming increasingly popular for controlling seepage of groundwater and hazardous wastes. They are also gaining acceptance for construction of underground facilities. The technique involves the excavation of a narrow trench in the presence of a bentonitic fluid or slurry. The slurry acts to support the open trench until it is backfilled with an impermeable material. The increase in popularity of these walls has been aided by the development of new construction techniques. These techniques offer the designer a wide range of engineering properties for the cutoff wall. However, there are few published guidelines on the selection of slurry trench cutoffs. This has resulted in situations where the cutoff wall selected was originally designed for a totally different application. The net effect in these cases has been poor performance and an unsatisfactory cutoff wall.This paper examines the principal methods of constructing slurry trench cutoffs, establishes their engineering characteristics, and presents a procedure for selecting a slurry trench cutoff. The factors which influence the selection are identified and discussed. The methodology of the selection process is reviewed with an example. This review and examination of the selection procedure demonstrates that it is an effective method of compiling and systematically analyzing the relevant factors affecting selection of slurry trench cutoffs.

scholarly journals A New Approach for Centrifugal Impeller Preliminary Design and Aerothermal Analysis

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Fangyuan Lou ◽  
John C. Fabian ◽  
Nicole L. Key
Keyword(s):  
Sensitivity Study ◽  
Operating Conditions ◽  
New Method ◽  
Centrifugal Impeller ◽  
Preliminary Design ◽  
New Approach ◽  
Relative Diffusion ◽  
Wide Range ◽  
Effectiveness Parameter ◽  
Selection Of

This paper introduces a new approach for the preliminary design and aerothermal analysis of centrifugal impellers using a relative diffusion effectiveness parameter. The relative diffusion effectiveness is defined as the ratio of the achieved diffusion to the maximum available diffusion in an impeller. It represents the quality of the relative diffusion process in an impeller. This parameter is used to evaluate impeller performance by correlating the relative diffusion effectiveness with the impeller isentropic efficiency using the experimental data acquired on a single-stage centrifugal compressor (SSCC). By including slip, which is appropriate considering it is an inviscid effect that should be included in the determination of maximum available diffusion in the impeller, a linear correlation between impeller efficiency and relative diffusion effectiveness resulted for all operating conditions. Additionally, a new method for impeller preliminary design was introduced using the relative diffusion effectiveness parameter, in which the optimal design is selected to maximize relative diffusion effectiveness. While traditional preliminary design methods are based on empirical loss models or empirical knowledge for selection of diffusion factor (DF) in the impeller, the new method does not require any such models, and it also provides an analytical approach for the selection of DF that gives optimal impeller performance. Validation of the method was performed using three classic impeller designs available in the open literature, and very good agreement was achieved. Furthermore, a sensitivity study shows that the method is robust in that the resulting flow angles at the impeller inlet and exit are insensitive to a wide range of blockage factors and various slip models.

scholarly journals Geodiversity and Biodiversity of the Postglacial Landscape (Dębnica River Catchment, Poland)

2016 ◽  
Vol 35 (1) ◽  
pp. 5-28 ◽  
Author(s):  
Alicja Najwer ◽  
Janina Borysiak ◽  
Joanna Gudowicz ◽  
Małgorzata Mazurek ◽  
Zbigniew Zwoliński
Keyword(s):  
Evaluation Criteria ◽  
Natural Vegetation ◽  
New Approach ◽  
River Catchment ◽  
Plant Associations ◽  
Wide Range ◽  
Analytical Algorithm ◽  
Landscape Ecological ◽  
Factor Maps ◽  
Selection Of

Abstract The preparation of a proper zoning plan or landscape-ecological plan requires taking into account recognition of the natural values of an area covered by the plan and evaluating its abiotic and biotic diversities. The aim of the paper is to present the new approach to the procedure of geodiversity and biodiversity assessment. This procedure is used to characterise abiotic and biotic heterogeneity of the postglacial landscape modified by a man, tested on Dębnica River catchment (Western Pomerania, Poland). This catchment is a representative example illustrating the landscape of Central European Plain. The analytical algorithm of the geodiversity assessment is based on appropriate selection of the evaluation criteria: lithological, relative heights, landform fragmentation, hydrographical elements and mesoclimatic conditions. Biodiversity was assessed on the basis of real vegetation, potential natural vegetation and the degree of anthropisation of the natural vegetation with respect to syngenesis of plant associations. Seven factor maps were obtained: five for the diversity of abiotic elements, and two for the diversity of biotic elements, which became the basis for the creation of total geodiversity and biodiversity maps. Maps produced in accordance with given methodology may find a wide range of applications.

Identifying Measurement Invariant Item Sets in Cross-Cultural Settings Using an Automated Item Selection Procedure

Methodology ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 177-188 ◽  
Author(s):  
Martin Schultze ◽  
Michael Eid
Keyword(s):  
Measurement Invariance ◽  
Optimal Solution ◽  
Selection Procedure ◽  
Cross Cultural ◽  
Item Selection ◽  
Ant System ◽  
Item Quality ◽  
Ant System Algorithm ◽  
Selection For ◽  
Selection Of

Abstract. In the construction of scales intended for the use in cross-cultural studies, the selection of items needs to be guided not only by traditional criteria of item quality, but has to take information about the measurement invariance of the scale into account. We present an approach to automated item selection which depicts the process as a combinatorial optimization problem and aims at finding a scale which fulfils predefined target criteria – such as measurement invariance across cultures. The search for an optimal solution is performed using an adaptation of the [Formula: see text] Ant System algorithm. The approach is illustrated using an application to item selection for a personality scale assuming measurement invariance across multiple countries.

COMBINATORIAL POLYNOMIALLY COMPUTABLE CHARACTERISTICS OF SUBSTITUTIONS AND THEIR PROPERTIES

2020 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
VLADIMIR NIKONOV ◽  
◽  
ANTON ZOBOV ◽  
Keyword(s):  
Mathematical Expectation ◽  
Point Of View ◽  
Small Range ◽  
Computational Point ◽  
Wide Range ◽  
Bijective Function ◽  
The Difference ◽  
Element Base ◽  
Selection Of

The construction and selection of a suitable bijective function, that is, substitution, is now becoming an important applied task, particularly for building block encryption systems. Many articles have suggested using different approaches to determining the quality of substitution, but most of them are highly computationally complex. The solution of this problem will significantly expand the range of methods for constructing and analyzing scheme in information protection systems. The purpose of research is to find easily measurable characteristics of substitutions, allowing to evaluate their quality, and also measures of the proximity of a particular substitutions to a random one, or its distance from it. For this purpose, several characteristics were proposed in this work: difference and polynomial, and their mathematical expectation was found, as well as variance for the difference characteristic. This allows us to make a conclusion about its quality by comparing the result of calculating the characteristic for a particular substitution with the calculated mathematical expectation. From a computational point of view, the thesises of the article are of exceptional interest due to the simplicity of the algorithm for quantifying the quality of bijective function substitutions. By its nature, the operation of calculating the difference characteristic carries out a simple summation of integer terms in a fixed and small range. Such an operation, both in the modern and in the prospective element base, is embedded in the logic of a wide range of functional elements, especially when implementing computational actions in the optical range, or on other carriers related to the field of nanotechnology.

Combination of ribosome and phage display for fast selection of high affinity VHH antibody fragments

2019 ◽  
pp. 27-33
Author(s):  
YuE Kravchenko ◽  
SV Ivanov ◽  
DS Kravchenko ◽  
EI Frolova ◽  
SP Chumakov
Keyword(s):  
Phage Display ◽  
Selection Procedure ◽  
Free System ◽  
Phage Displays ◽  
High Affinity ◽  
Binding Domains ◽  
A Cell ◽  
Vhh Antibodies ◽  
Efficiency Of Selection ◽  
Selection Of

Selection of antibodies using phage display involves the preliminary cloning of the repertoire of sequences encoding antigen-binding domains into phagemid, which is considered the bottleneck of the method, limiting the resulting diversity of libraries and leading to the loss of poorly represented variants before the start of the selection procedure. Selection in cell-free conditions using a ribosomal display is devoid from this drawback, however is highly sensitive to PCR artifacts and the RNase contamination. The aim of the study was to test the efficiency of a combination of both methods, including pre-selection in a cell-free system to enrich the source library, followed by cloning and final selection using phage display. This approach may eliminate the shortcomings of each method and increase the efficiency of selection. For selection, alpaca VHH antibody sequences suitable for building an immune library were used due to the lack of VL domains. Analysis of immune libraries from the genes of the VH3, VHH3 and VH4 families showed that the VHH antibodies share in the VH3 and VH4 gene groups is insignificant, and selection from the combined library is less effective than from the VHH3 family of sequences. We found that the combination of ribosomal and phage displays leads to a higher enrichment of high-affinity fragments and avoids the loss of the original diversity during cloning. The combined method allowed us to obtain a greater number of different high-affinity sequences, and all the tested VHH fragments were able to specifically recognize the target, including the total protein extracts of cell cultures.

Factors Affecting Molecular Self-Assembly and Its Mechanism

2012 ◽  
Vol 9 (1) ◽  
pp. 43 ◽  
Author(s):  
Hueyling Tan
Keyword(s):  
Self Assembly ◽  
Building Blocks ◽  
Molecular Engineering ◽  
Molecular Structures ◽  
Polymer Science ◽  
New Approach ◽  
Factors Affecting ◽  
Dna Structures ◽  
Self Assembling ◽  
Wide Range

Molecular self-assembly is ubiquitous in nature and has emerged as a new approach to produce new materials in chemistry, engineering, nanotechnology, polymer science and materials. Molecular self-assembly has been attracting increasing interest from the scientific community in recent years due to its importance in understanding biology and a variety of diseases at the molecular level. In the last few years, considerable advances have been made in the use ofpeptides as building blocks to produce biological materials for wide range of applications, including fabricating novel supra-molecular structures and scaffolding for tissue repair. The study ofbiological self-assembly systems represents a significant advancement in molecular engineering and is a rapidly growing scientific and engineering field that crosses the boundaries ofexisting disciplines. Many self-assembling systems are rangefrom bi- andtri-block copolymers to DNA structures as well as simple and complex proteins andpeptides. The ultimate goal is to harness molecular self-assembly such that design andcontrol ofbottom-up processes is achieved thereby enabling exploitation of structures developed at the meso- and macro-scopic scale for the purposes oflife and non-life science applications. Such aspirations can be achievedthrough understanding thefundamental principles behind the selforganisation and self-synthesis processes exhibited by biological systems.

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