scholarly journals Theoretical analysis of hydromixture transport

2020 ◽  
pp. 41-49
Author(s):  
Slavica Mihajlović ◽  
Ljubinko Savić ◽  
Dragana Radosavljević ◽  
Ljiljana Savić ◽  
Marina Blagojev ◽  
...  
Keyword(s):  
Solid Phase ◽  
Unstable Flow ◽  
Mixture Volume ◽  
Unsteady Operation ◽  
Mathematical Equations ◽  
Material Grain Size ◽  
Working Parameters ◽  
And Control ◽  
Transported Material ◽  
Theoretical Considerations

This paper presents theoretical considerations and working parameters analyzes of hydrotransport during unstable flow. The variable flow of hydraulic mixture in installations causes unsteady operation and pipes spraying, pump damage, obturation in various sections of the pipeline, reduced capacity as well as higher operating costs. Using mathematical equations presented in this paper, such parameters of the hydraulic mixture, hydrotransport installation and control devices can be determined which protect system from possible clogging. Considering the fact that critical speed of hydraulic mixture depends on transported material grain size, mixture volume mass, diameter of pipeline and specific gravity of solid phase, it is possible to accurately analyze obturation in hydrotransport installations depending on those parameters. In order to prevent hydraulic impacts in hydrotransport installation pipelines, which value can be determined mathematically, it is necessary to adjust installation to hydromixture parameters and pump, or vice versa.

scholarly journals Design, Construction, and Control for an Underwater Vehicle Type Sepiida

Robotica ◽  
2020 ◽  
pp. 1-18
Author(s):  
M. Garcia ◽  
P. Castillo ◽  
E. Campos ◽  
R. Lozano
Keyword(s):  
Embedded System ◽  
Closed Loop ◽  
Underwater Vehicle ◽  
Mathematical Representation ◽  
Closed Loop System ◽  
Vehicle Type ◽  
Mathematical Equations ◽  
And Control ◽  
Design Construction

SUMMARY A novel underwater vehicle configuration with an operating principle as the Sepiida animal is presented and developed in this paper. The mathematical equations describing the movements of the vehicle are obtained using the Newton–Euler approach. An analysis of the dynamic model is done for control purposes. A prototype and its embedded system are developed for validating analytically and experimentally the proposed mathematical representation. A real-time characterization of one mass is done to relate the pitch angle with the radio of displacement of the mass. In addition, first validation of the closed-loop system is done using a linear controller.

Generative Approaches to Syntax

2018 ◽  
Author(s):  
Simin Karimi
Keyword(s):  
Complex Predicates ◽  
Close Attention ◽  
Resultative Constructions ◽  
Differential Object Marking ◽  
Object Marking ◽  
And Control ◽  
Theoretical Considerations

This chapter offers an overview of some of the major syntactic and morphosyntactic properties of Persian. Of the topics introduced in this chapter, three have extensively been examined by various researchers over several decades: complex predicates, Ezafe constructions, and differential object marking. Issues related to scrambling, wh-constructions, and raising and control have also been discussed. Some of the issues introduced in this chapter have not been thoroughly examined in the literature. For example, problems related to complex DPs, specifically with respect to extraposition of the CP out of the complex DP, require close attention. Furthermore, the nature of resultative constructions, and whether Persian allows secondary predicate constructions need to be examined. Finally, this chapter touches on some topics that are under-studied: modality, negation, aspect, ellipsis, and sluicing. Due to the descriptive nature of this chapter, theoretical considerations are not thoroughly discussed, although briefly mentioned in some cases.

From Jonestown to 9/11 and Beyond

2016 ◽  
Author(s):  
Rebecca Moore
Keyword(s):  
Public Perceptions ◽  
Religious Violence ◽  
Religious Movements ◽  
New Religious Movements ◽  
Political Landscape ◽  
Branch Davidians ◽  
Internal Forces ◽  
Mass Murders ◽  
And Control ◽  
Theoretical Considerations

This chapter examines violent outbursts perpetrated by New Religious Movements (NRMs) and considers the competing and complementary theories that have arisen to explain them. It argues that theories about cult violence change as new data become available. Public perceptions of cults and a shifting religious-political landscape also shape theoretical considerations of religion and violence. The chapter notes that prior to the mass murders-suicides in Jonestown, Guyana, and immediately following, theories of violence focused on inwardly-directed coercion and control. The demise of the Branch Davidians in 1993, along with other eruptions of violence in the 1990s, challenged this perspective, and a theory of interaction between external and internal forces arose. The events of September 11, 2001 internationalized considerations of religious violence, and returned attention to the influence of apocalyptic worldviews. A pressing problem that has emerged most recently is the violence perpetrated against NRMs, particularly state-sponsored repression.

scholarly journals Innovative Visualization System Designed to Monitor Parameters of Mining Systems Operation

2018 ◽  
Vol 1 (1) ◽  
pp. 361-368
Author(s):  
Dawid Szurgacz ◽  
Jarosław Brodny
Keyword(s):  
Hard Coal ◽  
Visualization System ◽  
Technical Parameters ◽  
Operation Process ◽  
Hard Coal Mining ◽  
Innovative System ◽  
Working Parameters ◽  
And Control ◽  
Selection Of ◽  
Roof Support

Abstract Mining machines suitable for hard coal mining, due to the specifics of this industry must be characterized by very high technical parameters. In particular, it concerns their durability, reliability and availability. Currently used machines approved for operation in underground conditions meet such requirements. Nevertheless, during their operation it is reasonable to conduct supervision and control of work parameters. This applies to both machine manufacturers and users, which is especially important in the event of a failure. Mine employees should be able control of the entire operation process. This control can be effective thanks to a visualization system developed to monitor the working parameters of mining systems. The paper discusses the innovative system and presents the results of efficiency tests. They concerned the visualization of the operation of a powered roof support. The obtained results indicate that the assumed goal of the system has been achieved. The system is built on elements of industrial automation, which guarantees the reliability of the indicated values. Its graphic layout and selection of the presented parameters are also approved. It should also be emphasized that the system can work with currently operating systems and is easy to expand. According to the Authors, the system should find a wide application in practice.

scholarly journals Manganese carbonate-zinc glycerolate, synthesis, characterization and application as catalyst for transesterification of soybean oil

2016 ◽  
Vol 22 (4) ◽  
pp. 431-443
Author(s):  
Xiaochan Zhu ◽  
Hui Liu ◽  
Dejan Skala
Keyword(s):  
Soybean Oil ◽  
Solid Phase ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Mixed System ◽  
Solid Catalyst ◽  
Manganese Carbonate ◽  
Gravimetric Analysis ◽  
Working Parameters

In this study, mixed system containing manganese carbonate (MnCO3) and zinc glycerolate (ZnGly) was synthesized, and tested as solid catalyst for transesterification of soybean oil and biodiesel production. The samples of MnCO3/ZnGly before and after usage for transesterification process were characterized using different techniques: determination of basic strength, determination of specific surface area according to Brunauer-Emmett-Teller (BET), measuring the mass change using thermal gravimetric analysis (TGA), investigating the solid phase content and presence of different specific elements and groups by X-Ray diffraction (XRD), the Fourier transform infrared (FT-IR) spectroscopy, the scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The effects of different working parameters of transesterification were also investigated: temperature (438-458K), duration of transesterification (0-3.5h), methanol to oil molar ratio (12:1-36:1) and used amounts of catalyst (1-5 mass%). The reusability and stability of MnCO3/ZnGly were analyzed and obtained results showed that MnCO3/ZnGly exhibited a good activity with 100% TG conversion and 81.5% FAME yield with fresh catalyst, and can give 95-100% TG conversion and 62-78% FAME yield after 13 repeated use of same amount of catalyst without regeneration processes. Content of Mn and Zn in biodiesel and glycerol was analyzed by ICP-AAS after each reuse of catalyst.

scholarly journals Solidification and superlubricity with molecular alkane films

2019 ◽  
Vol 116 (51) ◽  
pp. 25418-25423 ◽  
Author(s):  
Alexander M. Smith ◽  
James E. Hallett ◽  
Susan Perkin
Keyword(s):  
Solid Phase ◽  
Molecular Layer ◽  
Friction Coefficients ◽  
Model Studies ◽  
Surface Alignment ◽  
Hydrocarbon Films ◽  
Nanoscale Films ◽  
Alkane Films ◽  
And Control ◽  
Single Molecular Layer

Hydrocarbon films confined between smooth mica surfaces have long provided an experimental playground for model studies of structure and dynamics of confined liquids. However, fundamental questions regarding the phase behavior and shear properties in this simple system remain unsolved. With ultrasensitive resolution in film thickness and shear stress, and control over the crystallographic alignment of the confining surfaces, we here investigate the shear forces transmitted across nanoscale films of dodecane down to a single molecular layer. We resolve the conditions under which liquid–solid phase transitions occur and explain friction coefficients spanning several orders of magnitude. We find that commensurate surface alignment and presence of water at the interfaces each lead to moderate or high friction, whereas friction coefficients down toμ≈0.001are observed for a single molecular layer of dodecane trapped between crystallographically misaligned dry surfaces. This ultralow friction is attributed to sliding at the incommensurate interface between one of the mica surfaces and the laterally ordered solid molecular film, reconciling previous interpretations.

Study on Determination Method of the Volatile Organic Compounds Emissions from Particleboards for Indoor Finishing

2011 ◽  
Vol 250-253 ◽  
pp. 935-938 ◽  
Author(s):  
Shi Jing Sun ◽  
Jun Shen ◽  
Zhong Yuan Zhao
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Solid Phase ◽  
Practical Method ◽  
Simple Operation ◽  
Good Shape ◽  
Volatile Organic ◽  
Static Head ◽  
And Control ◽  
Larix Gmelini

In order to comprehensive understand and control volatile organic compounds (VOCs) release from particleboards, this paper takes Larix gmelini particleboard as example and analyzes VOCs by three different methods. First of all, VOCs of Larix gmelini particles were detected by the static head space solid-phase micro-extraction (HS-SPME) technique. Secondly Larix gmelini particleboards were analyzed using the method of adsorbed by activated carbon, desorpted with methylene dichloride and measured by GC/MS. Finally, Tenax-T Thermal desorption -GC/MS was used to qualitative VOCs emissions. The best method for determination VOCs from particleboards was found. SPME is a simple operation method with short time. But the pretreatment of sample was troublesome and it is not easily measured for lower concentration particleboards. Active carbon absorption method is not suitable for quantitative because of much error in extraction. It is suitable for qualitative analysis. Tenax-T is a simple operation way with short analysis time and good shape of chromatographic. It is a convenient and practical method. Further study of VOCs emission of panels can be supported by this method.

scholarly journals Effect of Model Sorptive Phases on Phenanthrene Biodegradation: Molecular Analysis of Enrichments and Isolates Suggests Selection Based on Bioavailability

2000 ◽  
Vol 66 (7) ◽  
pp. 2703-2710 ◽  
Author(s):  
M. Friedrich ◽  
R. J. Grosser ◽  
E. A. Kern ◽  
W. P. Inskeep ◽  
D. M. Ward
Keyword(s):  
Natural Organic Matter ◽  
Contaminated Soils ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Solid Phase ◽  
Cation Exchange Resin ◽  
16S Rrna Sequence ◽  
Enrichment Cultures ◽  
Gradient Gel Electrophoresis ◽  
Weak Cation Exchange ◽  
And Control

ABSTRACT Reduced bioavailability of nonpolar contaminants due to sorption to natural organic matter is an important factor controlling biodegradation of pollutants in the environment. We established enrichment cultures in which solid organic phases were used to reduce phenanthrene bioavailability to different degrees (R. J. Grosser, M. Friedrich, D. M. Ward, and W. P. Inskeep, Appl. Environ. Microbiol. 66:2695–2702, 2000). Bacteria enriched and isolated from contaminated soils under these conditions were analyzed by denaturing gradient gel electrophoresis (DGGE) and sequencing of PCR-amplified 16S ribosomal DNA segments. Compared to DGGE patterns obtained with enrichment cultures containing sand or no sorptive solid phase, different DGGE patterns were obtained with enrichment cultures containing phenanthrene sorbed to beads of Amberlite IRC-50 (AMB), a weak cation-exchange resin, and especially Biobead SM7 (SM7), a polyacrylic resin that sorbed phenanthrene more strongly. SM7 enrichments selected for mycobacterial phenanthrene mineralizers, whereas AMB enrichments selected for a Burkholderia sp. that degrades phenanthrene. Identical mycobacterial andBurkholderia 16S rRNA sequence segments were found in SM7 and AMB enrichment cultures inoculated with contaminated soil from two geographically distant sites. Other closely relatedBurkholderia sp. populations, some of which utilized phenanthrene, were detected in sand and control enrichment cultures. Our results are consistent with the hypothesis that different phenanthrene-utilizing bacteria inhabiting the same soils may be adapted to different phenanthrene bioavailabilities.

Capital Projects

1995 ◽  
Vol 1 (2) ◽  
pp. 155-249 ◽  
Author(s):  
C.G. Lewin ◽  
S.A. Carne ◽  
N.F.C. de Rivaz ◽  
R.E.G. Hall ◽  
K.J. McKelvey ◽  
...  
Keyword(s):  
Risk Analysis ◽  
Private Sector ◽  
Present State ◽  
Joint Ventures ◽  
Discount Rates ◽  
Capital Projects ◽  
The Uk ◽  
And Control ◽  
Theoretical Considerations ◽  
Opening Up

ABSTRACTThe paper surveys the present state of knowledge about the appraisal and control of capital projects, and identifies the useful contribution which actuaries can make to the process.Relevant theoretical considerations are discussed, including the choice of appropriate discount rates for use by companies when screening proposals. It is recommended that discount rates should be lower than those commonly used. Some practical working methods are summarised and examples are given of how risk analysis can be carried out, for both simple and complex appraisals. Attention is drawn to the special ‘social’ considerations which may apply in the case of Government projects. The opportunities now opening up for joint ventures between the UK Government and private sector partners are examined, and it is concluded that proper sharing of costs and risks can facilitate arrangements which are acceptable to both sides.The paper concludes with a discussion of the procedures which companies can use to identify, appraise, control and monitor projects.

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