Effect of wood species and glue type on contact stresses in a mortise and tenon joint

Author(s):  
J Smardzewski

New technologies for wood building construction continue to employ various profile-adhesive joints, with mortise and tenon joints being the most popular. Their strength depends both on the wood species and type of the applied glue, as well as the execution accuracy of individual elements. The aim of the performed experiments was to determine the size of normal stresses in places of mutual pressures of the tenon and mortise and the impact of the change of wood species and the type of glue (or lack of glue) applied to the joint on the value of those stresses. It was established, on the basis of numerical calculations, that the phenomena of the tenon and mortise contact are caused both by the bending of the tenon as well as by the torsion of the glue bond. Stresses in the direction perpendicular to the fibre course generating pressures exceeding wood compression strength turned out to be the most dangerous for the tenon and mortise joint. The value of the linear elasticity modulus of the glue bond exerts a decisive influence on the stress values caused by the mutual pressures of the elements of the examined joint.

2017 ◽  
pp. 111-140 ◽  
Author(s):  
R. Kapeliushnikov

The paper provides a critical analysis of the idea of technological unemployment. The overview of the existing literature on the employment effects of technological change shows that on the micro-level there exists strong and positive relationship between innovations and employment growth in firms; on the sectoral level this correlation becomes ambiguous; on the macro-level the impact of new technologies seems to be positive or neutral. This implies that fears of explosive growth of technological unemployment in the foreseeable future are exaggerated. Our analysis further suggests that new technologies affect mostly the structure of employment rather than its level. Additionally we argue that automation and digitalisation would change mostly task sets within particular occupations rather than distribution of workers by occupations.


Emerging technologies have always played an important role in armed conflict. From the crossbow to cyber capabilities, technology that could be weaponized to create an advantage over an adversary has inevitably found its way into military arsenals for use in armed conflict. The weaponization of emerging technologies, however, raises challenging legal issues with respect to the law of armed conflict. As States continue to develop and exploit new technologies, how will the law of armed conflict address the use of these technologies on the battlefield? Is existing law sufficient to regulate new technologies, such as cyber capabilities, autonomous weapons systems, and artificial intelligence? Have emerging technologies fundamentally altered the way we should understand concepts such as law-of-war precautions and the principle of distinction? How can we ensure compliance and accountability in light of technological advancement? This book explores these critical questions while highlighting the legal challenges—and opportunities—presented by the use of emerging technologies on the battlefield.


2019 ◽  
Vol 10 (4) ◽  
pp. 106
Author(s):  
Bader A. Alyoubi

Big Data is gaining rapid popularity in e-commerce sector across the globe. There is a general consensus among experts that Saudi organisations are late in adopting new technologies. It is generally believed that the lack of research in latest technologies that are specific to Saudi Arabia that is culturally, socially, and economically different from the West, is one of the key factors for the delay in technology adoption in Saudi Arabia. Hence, to fill this gap to a certain extent and create awareness about Big Data technology, the primary goal of this research was to identify the impact of Big Data on e-commerce organisations in Saudi Arabia. Internet has changed the business environment of Saudi Arabia too. E-commerce is set for achieving new heights due to latest technological advancements. A qualitative research approach was used by conducting interviews with highly experienced professional to gather primary data. Using multiple sources of evidence, this research found out that traditional databases are not capable of handling massive data. Big Data is a promising technology that can be adopted by e-commerce companies in Saudi Arabia. Big Data’s predictive analytics will certainly help e-commerce companies to gain better insight of the consumer behaviour and thus offer customised products and services. The key finding of this research is that Big Data has a significant impact in e-commerce organisations in Saudi Arabia on various verticals like customer retention, inventory management, product customisation, and fraud detection.


Horticulturae ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Athanasios Koukounaras

Greenhouse horticulture is one of the most intensive agricultural systems, with the advantages of environmental parameter control (temperature, light, etc.), higher efficiency of resource utilization (water, fertilizers, etc.) and the use of advanced technologies (hydroponics, automation, etc.) for higher productivity, earliness, stability of production and better quality. On the other hand, climate change and the application of high inputs without suitable management could have negative impacts on the expansion of the greenhouse horticulture sector. This special issue gathers twelve papers: three reviews and nine of original research. There is one review that focuses on irrigation of greenhouse crops, while a second surveys the effects of biochar on container substrate properties and plant growth. A third review examines the impact of light quality on plant–microbe interactions, especially non-phototrophic organisms. The research papers report both the use of new technologies as well as advanced cultivation practices. In particular, new technologies are presented such as dye-sensitized solar cells for the glass cover of a greenhouse, automation for water and nitrogen deficit stress detection in soilless tomato crops based on spectral indices, light-emitting diode (LED) lighting and gibberellic acid supplementation on potted ornamentals, the integration of brewery wastewater treatment through anaerobic digestion with substrate-based soilless agriculture, and application of diatomaceous earth as a silica supplement on potted ornamentals. Research studies about cultivation practices are presented comparing different systems (organic-conventional, aeroponic-nutrient film technique (NFT)-substrate culture), quantitative criteria for determining the quality of grafted seedlings, and of wild species as alternative crops for cultivation.


Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4663
Author(s):  
Janaina Cavalcanti ◽  
Victor Valls ◽  
Manuel Contero ◽  
David Fonseca

An effective warning attracts attention, elicits knowledge, and enables compliance behavior. Game mechanics, which are directly linked to human desires, stand out as training, evaluation, and improvement tools. Immersive virtual reality (VR) facilitates training without risk to participants, evaluates the impact of an incorrect action/decision, and creates a smart training environment. The present study analyzes the user experience in a gamified virtual environment of risks using the HTC Vive head-mounted display. The game was developed in the Unreal game engine and consisted of a walk-through maze composed of evident dangers and different signaling variables while user action data were recorded. To demonstrate which aspects provide better interaction, experience, perception and memory, three different warning configurations (dynamic, static and smart) and two different levels of danger (low and high) were presented. To properly assess the impact of the experience, we conducted a survey about personality and knowledge before and after using the game. We proceeded with the qualitative approach by using questions in a bipolar laddering assessment that was compared with the recorded data during the game. The findings indicate that when users are engaged in VR, they tend to test the consequences of their actions rather than maintaining safety. The results also reveal that textual signal variables are not accessed when users are faced with the stress factor of time. Progress is needed in implementing new technologies for warnings and advance notifications to improve the evaluation of human behavior in virtual environments of high-risk surroundings.


2021 ◽  
Vol 13 (11) ◽  
pp. 6372
Author(s):  
Vincenzo Varriale ◽  
Antonello Cammarano ◽  
Francesca Michelino ◽  
Mauro Caputo

The digital transformation of supply chains should revolutionize entire management processes and improve various aspects of sustainability. In particular, the plans of Industry 4.0 aim towards a digitization of several procedures by exploiting emerging technologies such as the Internet of Things, RFID and blockchain. The purpose of this study is to highlight how order and disruption events processes can be improved with the adoption of emerging technologies and how this reflects on the improvement of sustainability aspects. The study is based on the comparison of two simulation scenarios between three actors in the cheese supply chain. In particular, a first traditional scenario “as is” is simulated without the use of new technologies and is compared to a second scenario “to be” that adopts IoT, RFID and blockchain. The results show an improvement in time performance for managing both perfect and non-compliant orders. The developed framework highlights the impact of new technologies on sustainability aspects, showing further managerial implications.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Kendall A. Johnson ◽  
Clive H. Bock ◽  
Phillip M. Brannen

Abstract Background Phony peach disease (PPD) is caused by the plant pathogenic bacterium Xylella fastidiosa subsp. multiplex (Xfm). Historically, the disease has caused severe yield loss in Georgia and elsewhere in the southeastern United States, with millions of PPD trees being removed from peach orchards over the last century. The disease remains a production constraint, and management options are few. Limited research has been conducted on PPD since the 1980s, but the advent of new technologies offers the opportunity for new, foundational research to form a basis for informed management of PPD in the U.S. Furthermore, considering the global threat of Xylella to many plant species, preventing import of Xfm to other regions, particularly where peach is grown, should be considered an important phytosanitary endeavor. Main topics We review PPD, its history and impact on peach production, and the eradication efforts that were conducted for 42 years. Additionally, we review the current knowledge of the pathogen, Xfm, and how that knowledge relates to our understanding of the peach—Xylella pathosystem, including the epidemiology of the disease and consideration of the vectors. Methods used to detect the pathogen in peach are discussed, and ramifications of detection in relation to management and control of PPD are considered. Control options for PPD are limited. Our current knowledge of the pathogen diversity and disease epidemiology are described, and based on this, some potential areas for future research are also considered. Conclusion There is a lack of recent foundational research on PPD and the associated strain of Xfm. More research is needed to reduce the impact of this pathogen on peach production in the southeastern U.S., and, should it spread internationally, wherever peaches are grown.


Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Liselotte De Ligne ◽  
Jan Van den Bulcke ◽  
Jan M. Baetens ◽  
Bernard De Baets ◽  
Gang Wang ◽  
...  

AbstractThe effect of fungicidal components in wood has been known for ages, yet there is no method to assess the impact of such components on the durability of a wood species, as compared to other material characteristics that influence decay. In this paper, the importance of fungicidal effects on the natural durability of 10 wood species is assessed in relation to other decay-influencing factors with a new test, the so-called ‘paste test’. By comparing results from this test with the ‘mini-block test’, on both heartwood and leached sapwood, insight is gained into the significance of fungicidal components on the one hand and other material characteristics on the other hand. The durability of species such as Prunus avium was attributed mainly to fungicidal components. For species such as Pterocarpus soyauxii, durability seemed to be an effect of both fungicidal components and moisture-regulating components, while the latter seemed to be of main importance in regulating the decay of Aucoumea klaineana and Entandrophragma cylindricum. Wood-anatomical features, such as the parenchyma content (in case of brown rot fungi) and the vessel-fiber ratio, possibly affect degradation as well. This work shows that fungicidal components are not always of major importance for the durability of a wood species. The authors hereby emphasize the importance of moisture-regulating components and wood anatomy on the durability of wood.


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