scholarly journals Influence of the Aggregate-Pouring Sequence on the Efficiency of Plugging Inundated Tunnels through Drilling Ground Boreholes

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2698
Author(s):  
Xiangming Jiang ◽  
Shuang Hui ◽  
Wanghua Sui ◽  
Zhiyuan Shi ◽  
Jiahao Wang
Keyword(s):  
Particle Size ◽  
Coarse Aggregate ◽  
Early Stage ◽  
Water Pressure ◽  
Field Investigation ◽  
Fine Aggregate ◽  
Flowing Water ◽  
Cross Sectional ◽  
Selection Of

This paper presents an experimental and field investigation on the efficiency of plugging by pouring aggregate in different sequences through multiple boreholes in a tunnel with flowing water. There have been controversies surrounding the selection of the pouring order for different particle sizes of aggregates and the order in different boreholes. A visualized experimental setup is used to investigate the influence of the pouring orders on the efficiency of plugging through multiple boreholes under the flowing-water condition. A case study of the salvage of a flooded mine using ground directional boreholes was investigated and compared with the experimental results. The water-pressure difference at the aggregate-capping moment, when fine aggregate was poured first and coarse aggregate later, was relatively small, compared to that when fine aggregate was poured upstream and coarse aggregate, downstream. The result implies that the efficiency of plugging with the order of pouring fine aggregate first and coarse aggregate later in different boreholes is better than that with the order of pouring fine aggregate upstream and coarse aggregate downstream. When the poured aggregate is about to be capped, increasing the pouring intensity with the same or a larger particle size is more conducive to capping. The case study shows that pouring fine materials in the early stage reduced the cross-sectional area; in the later stage, the aggregate particle size was gradually increased, which can be helpful in forming an effective water-barrier section in the tunnel. The pouring of aggregate provided a base for cement grouting to form a water-plug section with a length of 106 m, resulting in a sealing efficiency of 100% for the case.

scholarly journals Challenges in the development of bio-based solvents: a case study on methyl(2,2-dimethyl-1,3-dioxolan-4-yl)methyl carbonate as an alternative aprotic solvent

2017 ◽  
Vol 202 ◽  
pp. 157-173 ◽  
Author(s):  
Saimeng Jin ◽  
Fergal Byrne ◽  
Con Robert McElroy ◽  
James Sherwood ◽  
James H. Clark ◽  
...  
Keyword(s):  
Early Stage ◽  
Toxicity Testing ◽  
Solubility Parameters ◽  
Hansen Solubility Parameters ◽  
Step Method ◽  
Methyl Carbonate ◽  
Synthetic Routes ◽  
Selection Of ◽  
Hansen Solubility

Many traditional solvents have drawbacks including sustainability and toxicity issues. Legislation, such as REACH, is driving the move towards less hazardous chemicals and production processes. Therefore, safer bio-based solvents need to be developed. Herein, a 10 step method has been proposed for the development of new bio-based solvents, which utilises a combination of in silico modelling of Hansen solubility parameters (HSPs), experimental Kamlet–Abboud–Taft parameters, a selection of green synthetic routes followed by application testing and toxicity measurements. The challenges that the chemical industry face in the development of new bio-based solvents are highlighted through a case study on methyl(2,2-dimethyl-1,3-dioxolan-4-yl)methyl carbonate (MMC), which can be synthesised from glycerol. Although MMC is an attractive candidate as a replacement solvent, simply being bio-derived is not enough for a molecule to be regarded as green. The methodology of solvent development described here is a broadly applicable protocol that will indicate if a new bio-based solvent is functionally proficient, and will also highlight the importance of early stage Kamlet–Abboud–Taft parameters determination and toxicity testing in the development of a green solvent.

scholarly journals SELECTION OF FACADE'S ALTERNATIVES OF COMMERCIAL AND PUBLIC BUILDINGS BASED ON MULTIPLE CRITERIA / KOMERCINĖS IR VIEŠOSIOS PASKIRTIES PASTATŲ FASADO ALTERNATYVŲ DAUGIAKRITERINĖ ATRANKA

2011 ◽  
Vol 15 (2) ◽  
pp. 189-203 ◽  
Author(s):  
Jonas Šaparauskas ◽  
Edmundas Kazimieras Zavadskas ◽  
Zenonas Turskis
Keyword(s):  
Management Practices ◽  
Early Stage ◽  
Design Management ◽  
Strategic Decisions ◽  
Building Facades ◽  
Project Life Cycle ◽  
Total Investment ◽  
Project Life ◽  
Selection Of

An appropriate mechanism for supporting design management practices at an early stage of project is crucial in terms of adding value over scope, time and total investment strategic decisions. The clients are not only interested in value for money in relation to the investment in project development but costs associated in operation and maintenance over project life cycle as well. These criteria make possible to evaluate design solutions which can be characterized by quantitative and qualitative criteria which possibly have different weight, dimension and direction of optimization (maximisation or minimization). The purpose of this article – is to compare different designs of building or its structure and to select the best alternative using criteria of optimality. Case study is demonstrated by selecting the best facade system to cover the building. For this purpose four alternatives of building facades are under consideration. Two criteria (out of three) indicate that for the case study the most preferable facade‘s alternative is gas silicate masonry, covered by Rockwool and “Minerit” facade plates. Santrauka Tinkamas sprendimų priėmimo mechanizmas projektuojant pastatą yra labai svarbus priimant strateginius investicijų sprendimus. Klientus yra suinteresuotas ne tik projekto įgyvendinimo kaina, bet ir eksploatavimo išlaidomis. Šio straipsnio tikslas – palyginti skirtingus pastato projektus arba konstrukcijas ir pagal tris optimalumo kriterijus parinkti geriausią alternatyvą. Šie trys kriterijai leidžia įvertinti projektinius sprendinius, kurie gali būti apibūdinami kiekybiniais ir kokybiniais rodikliais, turinčiais skirtingas dimensijas ir optimizavimo kryptį (maksimizavimas arba minimizavimas). Skaitiniame pavyzdyje demonstruojamas geriausios fasado sistemos parinkimas pastatui. Jame svarstomos keturios alternatyvos. Du kriterijai (iš trijų) rodo, kad šiam konkrečiam atvejui tinkamiausias yra fasadas, sumūrytas iš dujų silikato blokelių, aptaisytų ,,Rockwool“ mineraline vata ir ,,Minerit“ fasado plokštėmis.

scholarly journals Experimental Investigation on Mechanical Characteristics of Waterproof System for Near-Sea Tunnel: A Case Study of the Gongbei Tunnel

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1524
Author(s):  
Zhenliang Zhou ◽  
Zhongsheng Tan ◽  
Qiang Liu ◽  
Jinpeng Zhao ◽  
Zikai Dong
Keyword(s):  
Mechanical Characteristics ◽  
Water Pressure ◽  
Scale Model ◽  
Construction Process ◽  
Applied Water ◽  
Curtain Grouting ◽  
Free Drainage ◽  
Movement Joint ◽  
Selection Of

The water around thenear-sea tunnels is supplied infinitely, and mechanical characteristics of the lining and movement joint are inevitably affected by waterproof methods. The research on the mechanical characteristics of the waterproof system is immature. As a case study of the Gongbei tunnel, a scale model was established in this study, and the stratum, pipe curtain, grouting circle, lining, waterproof board, and movement joint were simulated based on the similarity theories. By changing the externally applied water pressure and drainage discharge, the variation and distribution of the water pressure and strain on the lining with the fully wrapped waterproof (FWW) method, the lining with the partially wrapped waterproof (PWW) method, and the movement joint were investigated. Furthermore, several suggestions on the selection of the waterproof method were presented. The results indicate that the PWW method can reduce the water pressure and strain on the lining under the drained state. Under the state of free drainage, the strain on the lining with the PWW method may get a discount of about 30%. More attention could be paid to the waterproof of the movement joints in the construction process, especially the invert. The research results may offer some valuable insights into the waterproof design of similar near-sea tunnels.

Study on the Synthesis of SiC Powder Material by Using Induction Heating System

2020 ◽  
Vol 1014 ◽  
pp. 38-42
Author(s):  
Fang Jiao ◽  
Zhou Li Wu ◽  
Dian Peng Cui ◽  
Mu Long Yang ◽  
Bo Yu Dong
Keyword(s):  
Particle Size ◽  
Large Particle ◽  
Early Stage ◽  
Heating System ◽  
Vapor Transport ◽  
Large Particle Size ◽  
High Quality ◽  
Material Source ◽  
Induction Heating System ◽  
Selection Of

By using a NAURA Advanced Physical Vapor Transport (PVT) System, the character ofthe synthesized SiC powder were studied. Mainly from the aspects of purity and particle size, and relevant experiments were designed to understand the influence of the powder source on the synthesized SiC powder. The results showed that the selection of Si powder source with appropriate particle size was conducive to increase the proportion of large particle size of SiC powder. In addition, the purification of material source in the early stage of the process was beneficial to improve the purity of SiC powder. The results showed successful preparation of optimized SiC powder and thus high-quality SiC wafers were made.

scholarly journals Selection of arbitrarily scaled cross-sections in bending stiffness design

2003 ◽  
Vol 217 (2) ◽  
pp. 113-125
Author(s):  
D Pasini ◽  
D J Smith ◽  
S C Burgess
Keyword(s):  
General Solution ◽  
Cross Sections ◽  
Performance Index ◽  
Selection Procedure ◽  
Performance Indices ◽  
Cross Sectional ◽  
Buckling Instability ◽  
Stiffness Design ◽  
Selection Of

Performance indices can be used to model the relative structural efficiency of different cross-sectional shapes. Performance indices have been previously defined mainly for structural cross-sections that are scaled proportionally in size. This paper extends the method of performance indices by allowing scaling of cross-sections in any direction. A novel feature of the method described in this paper is the inclusion of the space envelope as a design parameter. The first part of the paper gives a derivation of the general solution for the performance index. The second part presents a graphical selection procedure and discusses the efficiency limits of cross-sections due to buckling instability. It concludes with a case study to demonstrate the method.

Performance indices for arbitrarily scaled rectangular cross-sections in bending stiffness design

2002 ◽  
Vol 216 (2) ◽  
pp. 101-113
Author(s):  
D Pasini ◽  
S C Burgess ◽  
D J Smith
Keyword(s):  
Cross Sections ◽  
Performance Index ◽  
Graphical Method ◽  
Bending Stiffness ◽  
Performance Indices ◽  
Cross Sectional ◽  
Stiffness Design ◽  
Design Case Study ◽  
Selection Of

Performance indices are presented for the selection of optimal rectangular beams in bending stiffness design. Previous studies have developed performance indices for only three design cases: proportional scaling of width and height, constrained height and constrained width. This paper extends the methodology of the performance index to any arbitrary direction of scaling. The performance index has the form Eq/p, where q is a function only of the scaling vector between two cross-sectional envelopes of different materials. The paper also presents a graphical method for determining the performance of rectangular beams in stiffness design. The perormance index and the graphical method are applied to a design case study.

scholarly journals Influence of Business Characteristics on Selection of Investment Evaluation Techniques: The Case of Tanzanian SMEs

2018 ◽  
Vol 10 (4) ◽  
pp. 41
Author(s):  
Rose J. Katabi ◽  
Romanus L. Dimoso
Keyword(s):  
Financial Management ◽  
Sampling Technique ◽  
Sales Growth ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Frequency Distributions ◽  
Investment Evaluation ◽  
Evaluation Techniques ◽  
Selection Of

This study was conducted in two phases; first as a survey and second as a case study. The study used a cross-sectional survey design to explain the business characteristics influencing the selection of investment evaluation techniques among Tanzanian SMEs. Purposive sampling technique was used to collect data to a sample of 301 SMEs drawn from SIDO in Dar es Salaam and Dodoma regions. Data were collected though questionnaires and transformed into suitable format for analysis using statistical packages for the survey, while for the case study interviews were used. Statistical techniques used in this study were descriptive (frequency distributions) and inferential statistics (multivariate analysis) which were used to determine whether or not there is a relationship between business characteristics and selection of investment evaluation techniques.  Results of this study shows that, sales growth, industry of business, level of education and finance education of owners, were the business characteristics that influence the selection of investment evaluation techniques.Theoretical and practical contributions in the area of investment decisions for SMEs in Tanzania are made based on the findings of the study. On theoretical contributions, the study provided a better understanding on small business characteristics and how they influenced the selection of investment evaluation techniques. On practical contributions, owners should maintain high sales growth; improve education background by attending short courses on financial management, because these two characteristics significantly affect the selection of investment evaluation techniques.

scholarly journals THE USE OF REQUEST STRATEGIES OF INDUSTRIAL ENGINEERING STUDENTS

2020 ◽  
Vol 8 (2) ◽  
pp. 63
Author(s):  
Yoga Prihatin ◽  
Nur Aflahatun
Keyword(s):  
Engineering Students ◽  
Field Investigation ◽  
Industrial Engineering ◽  
Efl Learners ◽  
Completion Test ◽  
Request Strategies ◽  
Tone Of Voice ◽  
Testing Instruments ◽  
Selection Of

The aim of this study is to investigate the types of the request strategy used by Industrial Engineering students as EFL learners. Using qualitative data, this study discusses the use of request strategy in case-based teaching of foreign languages. The participants of the study are 37 Industrial engineering students who learnt English in the second semester. The testing instruments used were discourse completion task. For this aim, a discourse completion test was used to generate data related to the request strategies by each group. Selection of request situation in discourse completion test was based on three social factors of relative social distance, power, and rank of imposition. The participants� responses were analyzed according to the classifications of request strategy by Blum-Kulka & Olshtain. The case study findings indicate that 57% of Industrial Engineering students� responses mostly use conventional indirect strategies, 29.2 % responses are direct strategies, and 13 % responses belong to non-conventional indirect strategies. 49.7 % responses belong to query preparatory.� 17.8 %� responses� are identified as explicit performatives, 10.3 %� responses categorized as want statements, 9.2 % responses classified as strong hints, 6.5 % responses grouped as mild hints, 4.9 % responses recognized as suggestive formulas, and 1.6 % responses indicated as mood derivable. The indirectness is greatly influenced by students� cultural background, which belong to high-context culture. People in high context culture refer to the value cultures placing on indirect communication. A message is understood with a great deal of gesture, facial expressions, tone of voice, eye contact, body language, posture, and other ways people can communicate without using language. The findings of this study may set pedagogical implications for teachers, and learners of EFL therefore conducting a further field investigation is recommended to have in depth exploration�� about request strategies made by EFL Learners.

scholarly journals Repository Construction and Reuse of Software Requirement

2019 ◽  
Vol 9 (2) ◽  
pp. 907-909
Keyword(s):  
Software Development ◽  
Software Reuse ◽  
Early Stage ◽  
Actual Case ◽  
Software Requirement ◽  
Software Production ◽  
Initial Stage ◽  
Result Analysis ◽  
Selection Of

Software reuse is not limited to reusing code used a lot but can be used in all steps and activities related to software production. In particular, the reuse of requirements has various benefits by reusing reliable requirements, and the development of requirements is an early stage of software development and may have higher efficiency than the utilization of reuse in later stages if reuse is utilized from the initial stage. However, despite its many advantages, the study on the reuse of requirements is insufficient. Therefore, to explore the possibility of the requirements reuse, we conducted a total of four stages in this paper: selection of targets and stakeholders, construction of requirements repository, reuse of requirements repository, and result analysis, and a case study of requirements repository construction and reuse was conducted. We have confirmed the fact that the reuse of requirements possible with a high proportion in practice through the application of actual case and we have also confirmed the possibility of research on the reuse of requirements. If we deal with the reliable requirements by increasing the utilization of requirements reuse, the possibility of the project's success will also be greatly increased.

Fit and Congruency

2019 ◽  
Vol 18 (3) ◽  
pp. 148-156
Author(s):  
Mary Hogue ◽  
Lee Fox-Cardamone ◽  
Deborah Erdos Knapp
Keyword(s):  
Role Theory ◽  
Social Role ◽  
Gender Diversity ◽  
Job Fit ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Working Adults ◽  
Role Congruity ◽  
Self Selection ◽  
Selection Of

Abstract. Applicant job pursuit intentions impact the composition of an organization’s applicant pool, thereby influencing selection outcomes. An example is the self-selection of women and men into gender-congruent jobs. Such self-selection contributes to a lack of gender diversity across a variety of occupations. We use person-job fit and the role congruity perspective of social role theory to explore job pursuit intentions. We present research from two cross-sectional survey studies (520 students, 174 working adults) indicating that at different points in their careers women and men choose to pursue gender-congruent jobs. For students, the choice was mediated by value placed on the job’s associated gender-congruent outcomes, but for working adults it was not. We offer suggestions for practitioners and researchers.

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