Turbulent eddies in boundary layers on smooth and rough flat plate

CER65SC-EJP57.March 1966.Includes bibliographical references (pages 55-57).U.S. Army Material Command Washington 25, D.C.This study represents one in a series of boundary layer investigations which are undertaken in order to obtain a definition of the roughness characteristics of a surface from the turbulence structure in the boundary layer near the surface. It is attempted to discuss the effect of the roughness in the structure of the turbulent eddies found near the boundary by comparing space correlations and spectra which were measured in the boundary layer on smooth and rough flat plates. The experimental investigations were made with a flat plate placed at a height of 2.0 ft. from the floor of a wind tunnel which had a 6 ft. x 6 ft. cross- section. The size of the plate used was 6 ft. x 3 ft. To obtain a rough surface condition, gravel which passed through a #7 sieve and are retained on a #8 sieve was glued to the surface of the aluminum plate. The density of the roughness material was 120 particles per square inch. Mean velocity profiles were measured on six stations with ambient air velocity of 30 fps at a condition of zero pressure gradient which were obtained by constructing a false ceiling to the wind tunnel roof. The measurements were analyzed in terms of the "wall law" and the "velocity-defect law" for smooth walls, and agreement with the work of other investigators was found. The logarithmic part of the velocity distribution curve for the rough boundary is shifted parallel to the smooth curve by an amount ∆u/u*=12. The turbulence signals were recorded on magnetic tape. They were obtained by using two single hot-wires, one of which was fixed in position and embedded in the plate surface and the other was mounted on a probe actuator whose position was varied freely in x, y and z directions with respect to the fixed probe. From these data, the turbulent intensities, turbulent spectra, total space correlations and filtered space correlations were determined electronically. Comparison of the results for smooth boundary with those for the rough boundary shows that the smooth surface eddy retains the correlation coefficients for a longer time than that of the rough surface case. The parameter to define the roughness characteristic in the velocity field from the measurement of space correlations was expressed in terms of Lxs/Lxr where Lxs and Lxr is the mean eddy size for smooth and rough boundary respectively.Under grant DA-AMC-28-043-G20

Spatial variation of soil respiration on a drained peatland : a case study from Lettosuo-peatland, Finland

Soil respiration (Rs), especially from drained peatland, has a significant role in the global carbon cycle. Drained peatland adds more CO2 effluxes due to the aerobic condition and fast decomposition rate of organic matter. In such condition, peatlands are no more carbon sink rather than a source. However, soil respiration (Rs) is known to be markedly variable with time and space. Many ecological studies showed an exact measurement of Rs is critical. Even a spatial variability of Rs is less known at a plot scale. This study investigated the spatial variation of Rs and its relationship with some explanatory factors (soil temperature, water-table level, moss cover, drainage ditch distance, and vegetation cover) in Lettosuo-peatland, Tammela, Finland. Soil respiration (Rs), soil temperature (Ts), and water-table level (WTL) were measured at 98 sampling plots during May to August 2017. A closed chamber system is known as Environmental Gas Monitor (EGM) was used to measure soil respiration. Once at the end of the measurement in August, vegetation site type (St), ditch distance (Dd), field layer vegetation (FLV), and ground layer vegetation (peat moss (Mp), forest moss (Mf)) were measured. The results showed that the mean rate of CO2 efflux was 0.49 ± 0.1 ( ± Std) g CO2 m-2 h-1 at 13.51 ± 0.8 ( ± Std) °C (at 5 cm depth) ranging from 0.15 to 0.98 g CO2 m-2 h-1. A multiple linear model indicated (R2 =0.18) that about 18% of the spatial variation of Rs could be explained by Ts, WTL, and Dd collectively, but only WTL (R2 = 0.12) could explain 12% variation alone. The spatial variability of soil respiration was mainly driven by the variability in WTL

Application of artificial intelligence as a knowledge creation instrument in tax procedures

This study set out to find whether deep learning algorithms neural networks and self-organizing maps could be utilized in a value-adding way in the Finnish Tax Administration in the handling of income tax related claims by limited liability companies. According to research positive outcomes in artificial intelligence (AI) utilization have been attained outside Finland. The research was carried out according to the action design research method in which the focus of the research is concurrently building a suitable artifact for the organization and learning (design principles) from the creation and intervention itself. Research began with problem formulation followed by building, intervention, and evaluation. As a result, the project team consisting of three members created two functional artifacts: one based on neural networks, and another based on self-organizing maps. Creation of the artifacts was done in cycles as alpha, beta and gamma where alpha and beta were a neural network and gamma a self-organizing map. Alpha reached a macro average of 0.75–0.78 in classification and beta 0.77–0.79. Gamma gave a different point of view on the problem and was able to clearly identify the class's non-estimated customers in a topographical map. The artifacts were limited to function only as knowledge creation instruments due to legal and ethical limitations present in the context. Results suggest that it is recommendable to approach problems with more than one artifact. The preliminary results of this research were validated by applying the concept in a case organization, followed by an analysis of the results in an end-user setting.© 2024 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

Application of fuzzy TOPSIS framework for selecting complex project in a case company

Purpose This study aims to propose a method known as the fuzzy technique for order preference by similarity to ideal solution (fuzzy TOPSIS) for complex project selection in organizations. To fulfill study objectives, the factors responsible for making a project complex are collected through literature review, which is then analyzed by fuzzy TOPSIS, based on three decision-makers’ opinions. Design/methodology/approach The selection of complex projects is a multi-criteria decision-making (MCDM) process for global organizations. Traditional procedures for selecting complex projects are not adequate due to the limitations of linguistic assessment. To crossover such limitation, this study proposes the fuzzy MCDM method to select complex projects in organizations. Findings A large-scale engine manufacturing company, engaged in the energy business, is studied to validate the suitability of the fuzzy TOPSIS method and rank eight projects of the case company based on project complexity. Out of these eight projects, the closeness coefficient of the most complex project is found to be 0.817 and that of the least complex project is found to be 0.274. Finally, study outcomes are concluded in the conclusion section, along with study limitations and future works. Research limitations/implications The outcomes from this research may not be generalized sufficiently due to the subjectivity of the interviewers. The study outcomes support project managers to optimize their project selection processes, especially to select complex projects. The presented methodology can be used extensively used by the project planners/managers to find the driving factors related to project complexity. Originality/value The presented study deliberately explained how complex projects in an organization could be select efficiently. This selection methodology supports top management to maintain their proposed projects with optimum resource allocations and maximum productivity.© 2021, Ahm Shamsuzzoha, Sujan Piya and Mohammad Shamsuzzaman. Published by Emerald Publishing Limited. This article is published under the Creative Commons Attribution (CC BY 4.0) license. Anyone may reproduce, distribute, translate and create derivative works of this article (for both commercial and non-commercial purposes), subject to full attribution to the original publication and authors. The full terms of this license may be seen at http://creativecommons.org/licences/by/4.0/legalcodefi=vertaisarvioitu|en=peerReviewed

Optimal maintenance for a waste-to-energy plant using DEMATEL : A case study

Waste-to-energy (WtE) plants are complex systems that requiring different types of maintenance to be reliable and available in functionality. The inadequacies of WtE plant lifetime maintenance may increase the production costs and negatively affect the competitiveness and the availability of WtE plants. To keep the efficiency of all the plant systems high and operating as expected during their lifetime, it is important to maintain them. This study focuses on the maintenance of WtE plants by analyzing the operating procedures at a case company. In the study, a multi-criterion decision-making method (MCDM) named Decision-Making Trial and Evaluation Laboratory (DEMATEL) is used to evaluate the weight and rank of twelve identified criteria for spare parts of the case WtE company. The empirical part of this study consists of a qualitative study, where data were collected from an open-ended questionnaire survey and case company data from existing documents. The respondents' rate from the questionnaire survey was 20%. Key findings from the study show that human, economic, equipment and tool related, management, and environmental factors have an important impact on the effectiveness of the maintenance and availability of the WtE plant. The study also shows that quality, lead time, price, and the severity of spare part failure are the key criteria to consider when selecting spare parts for the WtE plant. The study recommends several initiatives to improve the availability of WtE plant and spare parts which will help to reduce the costs of maintenance as well as mitigate the risks related to the maintenance.© The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.fi=vertaisarvioitu|en=peerReviewed

A COMPARATIVE STUDY ON THE EFFECT OF LIQUOR RATIO OF ACID AND NEUTRAL(POWDER) ENZYME ON DENIM GARMENTS

Young people as well as older people have now great passion for the denim cloth. Today jeans are available in many colors and designs. In this study we tried to reveal the difference in between two types of cellulase enzymes acid and neutral (powder) enzyme. To do this, denim samples were collected and prepared according to the recipe of equal amount of enzyme by varying the liquor ratio. Basically there were no differences found in between acid and powder enzyme on different fastness properties like rubbing, washing, perspiration, light fastness test. But there was a significant difference in weight loss%. Acid enzyme exhibited little bit more enzymatic effect than powder enzyme and it also showed more weight loss % . But the neutral enzyme required less money rather than acid enzyme and no need to control pH, easy to use. Moreover, lower liquor ratio gave higher abrasion. Acid enzyme gave more back staining than neutral enzyme

Molecular characterization and resistance profile of nosocomial Acinetobacter baumannii in intensive care unit of tertiary care hospital in Bangladesh

This study was designed to investigate the resistance profile along with the genetic background of resistance to beta-lactam antibiotics among the nosocomial A. baumannii in Bangladesh. A. baumannii was confirmed by detecting blaOXA-51-like. Antibiotic susceptibility was determined by disk diffusion method. Agar dilution method was used to determine MIC of ceftazidime and imipenem. All A. baumannii were phenotypically screened for ampC, ESBL and MBL production. Genetic markers of antibiotic resistance such as blaampC, blaOXA-51, 23, 40, 58 and 143, blaKPC, blaIMP, blaVIM and blaNDM-1, genetic environment around blaADC and ISAba1 upstream of blaOXAs were evaluated by PCR. Twenty-four (96%) A. baumannii were considered as MDR. 96% A. baumannii were resistant to amoxiclav, ceftazidime, ciprofloxacin and cefoxitin, 92% to cefotaxime and piperacillin-tazobactam, 88% to cefepime, amikacin and imipenem, 52% to sulbactam-cefoperazone and 40% were resistant to aztreonam. All were sensitive to colistin. The distribution of several beta-lactamase genes such as blaOXA-51 (100%), blaADC-like (92%), blaNDM-1 (92%), EBC group (84%), blaOXA-23 (76%), blaVIM (72%), blaKPC (44%), DHA group (24%), blaOXA-58 (16%), ACC group (8%) and CIT group (4%) were observed among the 25 A. baumannii. This is the first reported plasmid mediated ampC beta-lactamases in A. baumannii. blaOXA-51 was positive in 100%, blaNDM-1 in 95.45%, blaOXA-23 in 77.27%, blaVIM in 72.73%, blaKPC in 50% and blaOXA-58 in 18.18% of imipenem resistant isolates. MDR profile of nosocomial A. baumannii would highlight the importance of standard guideline of antimicrobials use and infection control policy in the hospitals of Bangladesh.</jats:p

SME Development Challenges and Opportunities in Bangladesh: A Case Study on Poultry Hatcheries by Triple Triangle Framework (TTF)

In the last half decade, there has been a visible growth in the poultry industry of Bangladesh leading to an increase in the per capita availability and consumption of chicken meat and egg. Although this growth has resulted in the minimization of the gap of human protein requirement, but compared to other developing countries as well as developed countries, per capita meat consumption is still very much lower. So there is a vast opportunity to improve total poultry industry by setting proper strategy to manage challenges and using opportunities effectively as well as efficiently. As a result the prime objectives of researchers are to explore the challenges and opportunities of poultry hatcheries focusing on SME players. Primary data has been collected by in-depth interviews and focus group discussions with different tiers of poultry professionals. Major findings of the research are the knowledge gap in respect of competitive dynamics, strategic management, global linkage potentials and modern technologies as well as another prime constraint is funding and fund management in terms of accessibility, availability and affordability (3A)

Fisheries Reference Point and Stock Status of Croaker Fishery (Sciaenidae) Exploited from the Bay of Bengal, Bangladesh

This research evaluated fisheries reference points and stock status to assess the sustainability of the croaker fishery (Sciaenidae) from the Bay of Bengal (BoB), Bangladesh. Sixteen years (2001–2016) of catch-effort data were analyzed using two surplus production models (Schaefer and Fox), the Monte Carlo method (CMSY) and the Bayesian state-space Schaefer surplus production model (BSM) method. This research applies a Stock–Production Model Incorporating Covariates (ASPIC) software package to run the Schaefer and Fox model. The maximum sustainable yield (MSY) produced by all models ranged from 33,900 to 35,900 metric tons (mt), which is very close to last year’s catch (33,768 mt in 2016). The estimated B > BMSY and F < FMSY indicated the safe biomass and fishing status. The calculated F/FMSY was 0.89, 0.87, and 0.81, and B/BMSY was 1.05, 1.07, and 1.14 for Fox, Schaefer, and BSM, respectively, indicating the fully exploited status of croaker stock in the BoB, Bangladesh. The representation of the Kobe phase plot suggested that the exploitation of croaker stock started from the yellow (unsustainable) quadrant in 2001 and gradually moved to the green (sustainable) quadrant in 2016 because of the reduction in fishing efforts and safe fishing pressure after 2012. Thus, this research suggests that the current fishing pressure needs to be maintained so that the yearly catch does not exceed the MSY limit of croaker. Additionally, specific management measures should implement to guarantee croaker and other fisheries from the BoB