Design Standards
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2021 ◽  
pp. 136943322110480
Author(s):  
A.R. Dar ◽  
S. Vijayanand ◽  
M. Anbarasu ◽  
M. Adil Dar

Some of the past studies on cold-formed steel (CFS) battened built-up columns have resulted in the development of new design rules for predicting their axial strengths. However, the main drawbacks of such studies are that they are purely numerical and the numerical models developed for such parametric studies were validated using the test results on similar built-up column configurations, but not the exact ones. Therefore, experimental studies on CFS battened columns comprising of lipped channels are needed for verifying the accuracy of the proposed design rules for CFS battened columns. This paper reports an experimental study performed on CFS built-up battened columns under axial compression. Adequately spaced identical lipped channels in the back-to-back arrangement were used as chords and were connected by batten plates laterally with self-driving screws to form the built-up members. The dimensions of chords were fixed as per the geometric limits given out in the North American Specifications (NAS) for the design of CFS structural members. The sectional compactness of the chords and the overall slenderness of the built-up columns were varied by altering the thickness of the channels and height of the built-up columns, respectively. A total of 20 built-up sections were tested under uniform compression to investigate the behavioural changes in the built-up columns due to these variations. The behaviour assessment was made in terms of peak strengths, load–displacement response and failure modes of the test specimens. The current design standards on CFS structures were used to determine the design strengths and were compared against the test strengths for assessing their adequacy. Furthermore, as discussed in the beginning, the test strengths were used to verify the accuracy of the different relevant proposed design rules in the literature.


Author(s):  
Ahmed Ali Soliman Elsamahy, Nanees Abd Elhamid Elsayyad, Usa Ahmed Ali Soliman Elsamahy, Nanees Abd Elhamid Elsayyad, Usa

  Despite the importance of therapeutic tourism, it faces great obstacles that limit the growth of the sustainability of its development, among the main obstacles that stand in the way of sustaining the development of therapeutic tourism in Wadi El- Natroun is the existence of an urban phenomenon that did not follow sustainable development in its design, with the absence of coordination between the ministries and relevant bodies. It is the absence of specific mechanisms and methodology for how to choose the most important criteria and sustainable planning indicators to assess the sustainability of therapeutic resorts, as it is considered one of the most important pillars of development for the sustainability of therapeutic tourism, in order to preserve the therapeutic area's resources from pollution resulting from human use, both in construction and operation In this way. The research provides a clearer picture for enabling the sustainable development of therapeutic tourism in Wadi El- Natroun through the preparation of a methodology and guidebook to enhance the sustainability of therapeutic tourism resorts in the region and their application in way that enables development decision- makers in the region to make rational and logical decisions regarding enabling sustainable development for therapeutic tourism development in it. And through both parts of theoretical research and analysis of the current situation in the study area, the most important results were reached the conclusion of a methodology and a guideline of the most important controls, determinants and sustainability indicators. It contains three criteria with eighteen basic determinants and eighty- one main indicators with the value of indicative relative weights divided as follows: Indicators of planning and design standards with a value of (40%)- Environmental standards indicators with a value of (35%)- Administrative and societal standards indicators with a value of (25%) , that are Serve as a checklist for developers and investors when preparing therapeutic tourism resorts in the design, management and operation processes to enable the sustainability of the development of desert therapeutic tourism on the site.The research ends with a set of recommendations, the most important of which is the need to apply the methodology and guidebook to therapeutic tourism resorts that are being prepared for in the region, it is considered one of the most important decision- making tools when planning to develop sustainable therapeutic tourism in the study area.


Author(s):  
Sylvie Spraakman ◽  
Jean-Luc Martel ◽  
Jennifer Drake

Bioretention is a type of green stormwater infrastructure for the urban environment that mimics a natural hydrologic system by reducing peak flows and runoff volumes and encouraging infiltration and evapotranspiration. This study examines the complete water balance of a bioretention system located in Vaughan, Ontario, Canada, between 2018 and 2019. The water balance was further broken down by event size, where the event size was determined by rainfall frequency analysis. Recharge was the largest component of the water balance overall (86 % of inflow), as well as by event size. Evapotranspiration was the next largest water balance component (7 % of inflow overall), and was a significant component of inflow (21 %) when considering only small events (50 % probability of recurrence). Evapotranspiration is a slow but consistent process, averaging 2.3 mm/day overall and 2.9 mm/day during the growing season. Climate change is likely to bring more wet days and higher temperatures, which will impact the bioretention water balance by increasing evapotranspiration and inflow. Design standards for retention targets should be updated based on the most recent rainfall frequency analyses to adjust for changing climate conditions.


2021 ◽  
Vol 24 (3) ◽  
pp. 70-75
Author(s):  
Tetiana I. Sheiko ◽  
◽  
Kyrylo V. Maksymenko-Sheiko ◽  
◽  

In this paper, based on the R-functions theory, methods have been developed and equations have been constructed for the 3D printing of hex-head screws with Bristol, Pentalobe, Polydrive and other types of screw slots. Such screws are used both in personal computers and other high-end equipment. The Bristol slot has four or six radial grooved beams. The advantage of the design of this slot is the correct perpendicular, rather than tangential, vector of force application when the slot is rotated by a tool, which minimizes the risk of stripping out the slot. For this reason, the Bristol slot is used in soft metal screws. Compared to the internal hex, the Bristol slot allows a noticeably higher torque, only slightly higher than that of the Torx slot. This type of slot is used in aviation, high-end telecommunications equipment, cameras, air brakes, agricultural equipment, astronomical equipment, and foreign military equipment. Variations with a pin in the center are found in game consoles to prevent the use of a flat-blade screwdriver as an improvised key. The Pentalobe slot is a five-point slot designed by Apple and used in its products to limit unauthorized disassembly. It was first used in mid 2009 to mount MacBook Pro batteries. Its miniature version was used in the iPhone 4 and later models, in the MacBook Air (available since late 2010 models), and the MacBook Pro with Retina screens. The Polydrive slot is a starlike slot with rounded star points, used in the automotive industry for applications requiring high tightening torque. The Torq-set slot is a cross slot for fasteners requiring high tightening torque. The grooves are slightly offset, not intersecting at one point. Fasteners with this type of slot are used in military aviation, for example, in E-3, P-3, F-16, Airbus, Embraer, and Bombardier Inc. The Phillips Screw Company owns the trademark and manufactures fasteners with this type of slot. The slot design standards are National Aerospace Standard NASM 3781 and NASM 4191 for the ribbed version. The resulting equations for the surfaces of screws were checked during the modeling of the screws before 3D printing. The 3D printing technology allows us to reduce the cost and labor intensity of manufacturing products, including complex slot screws. The analytical recording of designed objects makes it possible to use alphabetic geometric parameters, complex superposition of functions, which, in turn, allows us to quickly change their design elements. The positivity property of the constructed functions at the internal points of an object is very convenient for the implementation of 3D printing.


2021 ◽  
Author(s):  
◽  
Emily Martin

<p><b>Enriching the Envelope Experience is a design strategy for an external retrofit to revitalise existing housing. The aim is to create warmer, drier, healthier homes without having to displace the occupants.</b></p> <p>For many New Zealander’s, inefficient housing is negatively affecting occupant health and wellbeing.</p> <p>Preventable health issues place pressure on healthcare systems, costing valuable resources. The climate, housing, and healthcare crisis desperately require improvements to existing housing for warmer, healthier, and happier homes. Currently, the design of New Zealand housing is inefficient for climate resulting in uncomfortable living conditions. There is a global dependence on finite resources, and the ongoing resource use will reach capacity. Desperate attention to the environmental and economic impact is needed to sustain the precious resources. NewZealand is obligated to reach the 2050 climate goals.</p> <p>The design of buildings needs attention to mitigate the 39% carbon emissions by the construction industry and achieve net-zero carbon housing goals.</p> <p>Lengthy rebuilds require displacing people from their homes and communities and increase the demand for housing and resources. The demolition and rebuild further adds to the significant waste issue.</p> <p>Therefore, there is an opportunity to improve the existing housing stock as a readily available resource.</p> <p>The 1940s-1960s State House is a standardized housing typology mass-produced in New Zealand, and often of poor condition, it was an appropriate site to investigate for a retrofit design strategy.</p> <p>A design framework informed by sustainable design standards, case studies and understanding of the 1940s-1960s house typology directed the design process. The research outcome resulted in an external wall design strategy to improve the occupants’ home experience.</p>


2021 ◽  
Author(s):  
◽  
Emily Martin

<p><b>Enriching the Envelope Experience is a design strategy for an external retrofit to revitalise existing housing. The aim is to create warmer, drier, healthier homes without having to displace the occupants.</b></p> <p>For many New Zealander’s, inefficient housing is negatively affecting occupant health and wellbeing.</p> <p>Preventable health issues place pressure on healthcare systems, costing valuable resources. The climate, housing, and healthcare crisis desperately require improvements to existing housing for warmer, healthier, and happier homes. Currently, the design of New Zealand housing is inefficient for climate resulting in uncomfortable living conditions. There is a global dependence on finite resources, and the ongoing resource use will reach capacity. Desperate attention to the environmental and economic impact is needed to sustain the precious resources. NewZealand is obligated to reach the 2050 climate goals.</p> <p>The design of buildings needs attention to mitigate the 39% carbon emissions by the construction industry and achieve net-zero carbon housing goals.</p> <p>Lengthy rebuilds require displacing people from their homes and communities and increase the demand for housing and resources. The demolition and rebuild further adds to the significant waste issue.</p> <p>Therefore, there is an opportunity to improve the existing housing stock as a readily available resource.</p> <p>The 1940s-1960s State House is a standardized housing typology mass-produced in New Zealand, and often of poor condition, it was an appropriate site to investigate for a retrofit design strategy.</p> <p>A design framework informed by sustainable design standards, case studies and understanding of the 1940s-1960s house typology directed the design process. The research outcome resulted in an external wall design strategy to improve the occupants’ home experience.</p>


Author(s):  
Iryna Kozlyuk ◽  
Yuliia Kovalenko

The problem of designing advanced computing systems in the class of structures of integrated modular avionics is considered. The unified topology of the internal network of the computer on the basis of Space Wire exchange channels and variants of its execution for various onboard applications is offered. Equivalent reliability schemes of each of the specific structures are introduced and the probabilities of trouble-free operation of each structure are analyzed. Families of graphic dependencies are given. The analysis of the existing principles and algorithms for testing multiprocessor multimodal onboard digital computer systems is given; the new testing algorithm for the multiprocessor systems which follows the software design standards for products of integrated modular avionics is offered. The structure of the unified automated workplace for checking the functional modules of integrated modular avionics is considered. Specific requirements inherent in the workplaces for testing integrated avionics are identified: an increased level of control of the hardware component of products; the ability to simulate the failure state of individual components of avionics to check the mode of reconfiguration of the computer system; modular construction of software with the division of verification tests into components performed at the level of each CPM and the computer as a whole in single-task and multitasking modes; openness of architecture of a workplace, which provides an ability to change the level of control complexity of a product and control of one class of complexity; intra-project unification of both hardware and software of the workstation of the inspection.


2021 ◽  
Vol 11 (18) ◽  
pp. 8334
Author(s):  
Andina Sprince ◽  
Tomass Kozlovskis ◽  
Rihards Gailitis ◽  
Juozas Valivonis ◽  
Kinga Korniejenko ◽  
...  

Creep and shrinkage of Cement and Concrete Composites (CCC) are significant properties that need to be considered to use these materials in practice. Many previous scientific studies revealed CCC creep characteristics under sustained compression and shrinkage, using traditional test methods from design standards. Because of the complexity of experimental procedures, CCC creep in tension has not been studied as close. Furthermore, there is no unified standard that proposes applicable testing methods or specific testing apparatus. This study examines the suitability of 2D—Digital Image Correlation (DIC) to observe the creep deformations of specimens under tension. Ordinary Portland cement (OPC) mortar with 1% polyvinyl alcohol (PVA) fibres has been investigated in the research. Compact tension (CT) specimens 150 × 150 × 12 mm (with a notch) were used. Creep deformations under sustained uniaxial tension (applied loading corresponding to 60% of the ultimate strength) were measured. DIC images were captured using an entry/mid-level DSLR camera. Results show that DIC is suitable for studying uniaxial tensile creep of cement and concrete composites. Deformation of specimens in tension was similar to that measured using the conventional method (using surface-attached gauges).


2021 ◽  
Author(s):  
Corey Peltier ◽  
Kristi L. Morin ◽  
Kimberly Vannest ◽  
April Haas ◽  
Joshua Pulos ◽  
...  

Students identified with emotional or behavioral disorders (EBD) display deficits across academic content areas, most notably in mathematics. We reviewed research on student-mediated math interventions for students with EBD. A total of 19 studies published between 1968 and 2019 met inclusion criteria, with 24 of 32 cases meeting the What Works Clearinghouse Pilot Single-Case Design Standards (Version 4.0) with or without reservations. Participants included 51 students identified with EBD, ages 8 to 16 years old. Results from visual analysis revealed 0 cases demonstrated strong evidence, 11 cases demonstrated moderate evidence, and 21 cases demonstrated weak evidence of intervention effects. The omnibus Tau-U was 74.35% (CI95 = 64.2% to 84.4%), representing data from 17 studies including 46 students. Implications for research and practice are discussed.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5141
Author(s):  
Edyta Bernatowska ◽  
Lucjan Ślęczka

This paper presents the results of experimental and numerical tests on angle members connected by one leg with a single row of bolts. This study was designed to determine which failure mode governs the resistance of such joints: net section rupture or block tearing rupture. Experimental tests were insufficient to completely identify the failure modes, and it was necessary to conduct numerical simulations. Finite element analysis of steel element resistance based on rupture required advanced material modelling, taking into account ductile initiation and propagation of fractures. This was realised using the Gurson–Tvergaard–Needleman porous material model, which allows for analysis of the joint across the full scope of its behaviour, from unloaded state to failure. Through experimental testing and numerical simulations, both failure mechanisms (net section and block tearing) were examined, and an approach to identify the failure mode was proposed. The obtained results provided experimental and numerical evidence to validate the strength function used in design standards. Finally, the obtained results of the load capacity were compared with the design procedures given in the Eurocode 3′s current and 2021 proposed editions.


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