High-resolution EBSD characterisation of friction stir welded nickel-copper alloy:Effect of the initial microstructure on microstructural evolution and mechanical properties

The effect of the initial structure on the microstructure and texture of the friction stir welded Monel 400 alloy joints was investigated. For this aim, Monel 400 alloy of two initially treated conditions, annealed and rolled, was studied. Orientation imaging microscopy with a step size of 70nm was used to characterise the microstructures of the joints. The mechanical properties were evaluated using Vickers hardness and nanoindentation tests. In the joint of the initial annealed alloy, continuous dynamic recrystallisation governed the grain structure formation. However, in the case of the initial rolled base material, discontinuous dynamic recrystallisation also occurred to cause more random texture, smaller grains, much more high-angle grain boundaries and higher dislocation densities. In the stir zone, the hardness and yielding strength increased respectively from 177 HV to 192 HV and 215.9 to 238.8MPa by changing the base metal from the initial annealed to rolled condition. In addition, the microstructural features of the different zones containing the texture components and grain boundaries were scrutinised thoroughly

Geomechanical characterization of a heterogenous rock mass using geological and laboratory test results: a case study of the Niobec Mine, Quebec

To conduct a successful geomechanical characterization of rock masses, an appropriate interpretation of lithological heterogeneity should be attained by considering both the geological and geomechanical data. In order to clarify the reliability and applicability of geological surveys for rock mechanics purposes, a geomechanical characterization study is conducted on the heterogeneous rock mass of Niobec Mine (Quebec, Canada), by considering the characteristics of its various identified lithological units. The results of previous field and laboratory test campaigns were used to quantify the variability associated to intact rock geomechanical parameters for the different present lithological units. The interpretation of geomechanical similarities between the lithological units resulted in determination of three main rock units (carbonatite, syenite, and carbonatite-syenite units). Geomechanical parameters of these rock units and their associated variabilities are utilized for stochastic estimation of geomechanical parameters of the heterogeneous rock mass using the Monte Carlo Simulation method. A comparison is also made between the results of probabilistic and deterministic analyses to highlight the presence of intrinsic variability associated with the heterogeneous rock mass properties. The results indicated that, for the case of Niobec Mine, the carbonatite-syenite rock unit could be considered as a valid representative of the entire rock mass geology since it offers an appropriate geomechanical approximation of all the present lithological units at the mine site, in terms of both the magnitude and dispersion of the strength and deformability parameters

Prevalence, antibiotic resistance and virulence of Enterococcus spp. isolated from traditional cheese types

BACKGROUND: Enterococci are naturally found in the gastrointestinal (GI) tract of animals and humans, as well as animal-derived foods and vegetables. We here aimed to determine the prevalence, antibiotic resistance, and virulence determinants of E. faecium and E. faecalis in traditional cheese in the North-west of Iran.MATERIALS AND METHODS: Fifty specimens of popular traditional cheese from dairy stores of Urmia and Tabriz, Iran, were collected. Identification of the genus and species of enterococci was done using molecular and phenotypic techniques.RESULTS: Forty-eight (96 %) of 50 traditional cheese samples were harboring Enterococcus spp, including Enterococcus faecalis (n= 40; 83.33 %) and E. faecium (n= 8; 16.67 %). The prevalence of enterococci ranged from 1.1×105 to 9.7×104 CFU/g, and 1.1×103 to 9.8×103 CFU/g in Urmia and Tabriz samples, respectively. Rifampicin resistance (n= 38; 79.2 %) was the most common pattern observed in the susceptibility test, which was followed by quinupristin/dalfopristin (n= 33; 68.75 %). Among E. faecalis isolates, cpd (100 %), ace (92.5 %) and gelE (87.5 %), and among E. faecium isolates, gelE (100 %) and asa1 (75 %) were found to have the most common virulence genes.CONCLUSION: E. faecalis was the predominant species, displaying more virulence determinants. It also had high antibiotic resistance, as compared to E. faecium. The enterococci identified here commonly expressed virulence and antibiotic resistance determinants. So, it is required to improve the maintenance and production quality of traditional cheese to avoid enterococci contamination

Construction and performance of the Karkheh Dam Complementary Cut-off Wall: an innovative engineering solution

Construction of a dam cut-off wall is one of the most challenging tasks in dam engineering given the deep excavations involved and the complex interactions between stiff cut-off walls and soft surrounding soils. Here, we present innovative solutions for the development of the Karkheh dam’s complementary cut-off wall in southwest Iran which is among the largest structures of this type worldwide with a maximum depth of 115 m. Due to excessive water seepage and high hydraulic gradient following the reservoir impoundment, additional measures were considered among which was the extension of the existing cut-off wall. The main goal was to decrease the hydraulic gradient of the seepage through the dam foundation. The construction of this new wall, which is called as the complementary wall here, was associated with a number of technical challenges among which were: the connection between the new and old walls; trenching and placing of plastic concrete wall through different dam body zones; and slurry loss during trenching through the dam body zones. The complementary wall was constructed successfully producing invaluable engineering experiences including: design of a U-shaped panel as the connecting panel; design of a new method for grouting through uniformly distributed filter/drain materials; and adding cement-based grouts to the cut-off wall panels to prevent slurry loss. The complementary wall helped to decrease both total seepage and the hydraulic gradient; for instance, in the right abutment, total seepage was cut for 25% and the hydraulic gradient was reduced from 0.2 to 0.095

Effect of stacking fault energy on the restoration mechanisms and mechanical properties of friction stir welded copper alloys

Pure copper and Cu-Zn plates were friction stir welded under the same condition to evaluate the effect of stacking fault energy on the microstructural evolution and mechanical properties of the joints. For this aim, microstructure and texture of the joints were systematically characterized by electron backscattered diffraction and transmission electron microscopy. Moreover, to study the mechanical properties of the different microstructural zones of the joints, nanoindentation tests were employed. The results showed that in pure copper, continuous dynamic recrystallization was the only restoration mechanism for the formation of new grains. By adding zinc into copper, namely decreasing slacking fault energy, both continuous and discontinuous dynamic recryslallizalion mechanisms occurred. To this end, the enct of sucking fault energy on the restoration mechanisms has been summarized by schematic models. Moreover, the effect of the resloration mechanisms on the yield strength and strain hardening behavior of the joints has been scrutinized. (C) 2018 The Authors. Published by Elsevier Ltd

Analyzing the Causal Factors Affecting the Online Sales Smart Contract and Their Consequences: A Systematic Review

Purpose: The online sales smart contract is a protocol that is prepared to set up an electronic smart agreement between the buyer and the seller and is concluded and executed automatically based on the information related to the terms of the contract. The aim of the current research is to identify the causal factors affecting the online sales smart contract and its consequences using a systematic review.Methods: A systematic review was used in this research. This method is one of the types of qualitative research methods that are used to investigate phenomena and identify categories based on research literature. The statistical population of the research includes all research articles obtained from quantitative and qualitative studies regarding smart contracts and smart contracts in both Persian and English languages. With the aim of identifying the factors affecting the smart sales contract and its consequences, finally, 30 articles related to the research topic in the period from 2009 to 2022 in Farsi and English were selected and studied with a systematic review approach, and the text of the articles was based on the application of the Grounded Theory approach and based on the MaxQda software, central and selective coding were performed and analyzed. Reliability and Cohen's kappa coefficient were used as a measure to replace validity and reliability.Findings: By analyzing the collected articles, 678 English and Farsi articles were identified in the coding stage, and after scientific investigations, 94 articles related to the research topic were categorized, and finally 30 articles were included.In the continuation of the data analysis process, the concepts were categorized into six categories of the central phenomenon, causal conditions, background conditions, intervening conditions, strategies, and consequences through the central coding. The current research led to the presentation of a paradigm model called online sales smart contract and its consequences using a systematic review.Conclusions: Online sales smart contracts are programs that are stored on the blockchain and are executed when predetermined conditions are met. They are typically used to automate the execution of an agreement so that all participants can be assured of the outcome immediately without the intervention of an intermediary or wasted time. They can also automate a workflow and trigger the next action when conditions are met. Smart sales contracts are efficient because they have completely solved the issue of trust. The smart sales contract uses blockchain to confirm, validate, record, and enforce the terms agreed between the parties The presented model clearly defines the effective causal factors of establishing an online smart seller and its consequences, and leading companies can use this proposed model in their online sales on the blockchain platform

Investigating the Factors and Consequences of the Intelligence Sale of Appliances and Sports Equipment in the Metaverse

Purpose: Sales intelligence involves conducting sales operations on a blockchain platform, utilizing smart contracts and artificial intelligence agents to directly monitor all network members. Intelligent sales and the effective use of data in the economic environment of the Metaverse can be crucial steps in gaining the trust and loyalty of customers. Utilizing innovative and intelligent methods for sales in the Metaverse can boost profits, enhance customer interaction, and establish stable relationships with them. The main challenge of selling in the Metaverse is the risk of impersonation and uncertainty surrounding companies and active users in that space. The implementation of intelligent systems, non-fungible tokens, blockchain technology, smart digital marketing, and artificial intelligence sales agents can enhance user trust and confidence, leading to more effective sales and increased profitability. The purpose of the current research is to investigate the factors and consequences of intelligence in the sale of sports appliances and equipment in the Metaverse. Method: The current research is qualitative. Therefore, two methods, systematic review and Grounded Theory, were used in combination. The statistical community in the Grounded Theory method consists of experts in the fields of business management, information management, and computer science. The sample size of this population, with theoretical saturation, was determined to be 13 people using purposeful and snowball sampling. MaxQDA 20 software was used for data analysis. The data collection tool used in the systematic review of library studies and in the Grounded Theory method was a semi-structured, in-depth interview with experts. Guba and Lincoln's qualitative measure of reliability, along with two quantitative measures, Cohen's kappa and Holstein's coefficient, were utilized to assess the validity and reliability of the research. Considering that the background of the research under study lacked the necessary enrichment to complete the paradigm model, the first step involved using a systematic review method to identify the factors and the central phenomenon of the model. In the continuation of the research, the Grounded Theory method was employed to identify intervening factors, contextual factors, strategies, and consequences, utilizing the expertise of experts. In total, 269 articles were identified on the research topic. After screening, 11 Persian articles from 2020 to 2022 and 20 English articles from 2022 to 2023 were found to be suitable in terms of subject and content, according to the opinion of university professors. After searching for Persian and English articles, the articles were screened. Following a thorough systematic review, the categories of the factors and sales intelligence were identified. The model was completed using the database method and employing open, central, and selective coding. After designing the questions for the qualitative questionnaire and receiving confirmation from supervisors, consultants, and university experts, data collection began. To enhance the validity of the research, a voice recorder was used during the interviews in addition to taking notes. After collecting the qualitative data through open coding, the data was divided into separate parts and analyzed to identify patterns, similarities, and differences. First, during the open coding stage, the categories were identified. Then, in the second stage of analysis, central coding was utilized. The purpose of this step was to establish the relationship between the identified categories in the open coding phase. This coding is called axial because it occurs around the axis of a category. At this stage, the variable of sales intelligence was investigated using the systematic review method with a focus on the phenomenon-oriented approach. An attempt was made to determine the relationship of other categories produced with it. Findings: The results obtained led to the identification of 109 open codes, 33 central codes, and 6 selective codes. Finally, a paradigm model titled "Intelligent Sales of Sports Equipment and Supplies" was presented. Through a systematic review, the following categories were identified as factors influencing sales intelligence with a positive effect: perceived risk, hedonic motivation, engaging interactions, 3D augmented reality catalogue, augmented reality digital content, augmented reality digital advertising, augmented reality applications, augmented reality lead generation, virtual reality branding, virtual reality rebranding, non-exchangeable tokens, and smart sales contracts. By utilizing the Grounded Theory method and experts' opinions, the categories for enhancing digital marketing metrics, digital products, social network promotion, virtual entrepreneurship opportunities, business development, product platform, and commercialization improvement were identified as the outcomes of strategy implementation. The strategy's impact on all events was evaluated positively. Using the Grounded Theory method, the categories of metadata, cloud space, big data, edge computing, artificial intelligence, digital marketing, and the Internet of Things were identified as contextual factors that positively impact the strategy. The categories of digital divide, privacy violation, identity hacking, data and information security, cybercrimes, and the ambiguity of laws and regulations were identified as background factors with a negative impact on the strategy. Conclusion: The obtained results led to the identification of 109 open codes, 33 central codes and 6 selective codes. Finally, the current research led to the presentation of a paradigm model with the title of intelligent sales of sports equipment

Geotechnical Parameters of Landslide-Prone Laflamme Sea Deposits, Canada: Uncertainties and Correlations

Due to inherent variability arising from unpredictable geological depositional and post-depositional processes, the geotechnical parameters of Laflamme sea clay deposits remain highly uncertain. This study aims to develop and apply a methodology to assess the uncertainties of geotechnical parameters using statistical distributions for a landslide-prone Saguenay Lac-Saint-Jean (SLSJ) region. We used the measured physical and mechanical parameters of Laflamme Sea clays of various locations in the SLSJ region to characterize the geotechnical parameters in a representative manner. Goodness-of-fit tests assign each physical and mechanical parameter a distribution function for their descriptive analysis. We found that the quality of these tests is significantly influenced by outliers. The detected outliers in the dataset considerably impact the distribution type and the uncertainties of the specific geotechnical parameter. Subsequently, appropriate distribution functions for each parameter were assigned after treating the outliers. The derived coefficient of variability values for the SLSJ region were significantly high in comparison to the literature with cone penetration test data being only the exception. Finally, the results indicated that the uncertainties of geotechnical parameters of the Saguenay-Lac-Saint-Jean region marine clays are high as compared to Scandinavian clays and are relatively comparable to other eastern Canadian clays