Capacity Of Connections Research Articles

Enhancing seismic performance of rigid and semi-rigid connections equipped with SMA bolts incorporating nonlinear soil-structure interaction

Nowadays, using smart connections can improve the performance of buildings with some recentering features that are from the superelastic behavior of Shape Memory Alloys (SMAs). It seems that there is different rigidity between the designed connection and the real one in Steel Moment-Resisting Frames (SMRFs), which can be considered as a problematic issue due to the importance of connections in seismic performance assessment. This paper aims to investigate the seismic limit-state capacities of rigid and semi-rigid connections implemented in the 3-Story, 5-Story, 7-Story, and 9-Story SMRFs considering the nonlinear Soil-Structure Interaction (SSI) effects. A Tcl programming code was developed to model semi-rigid connection and SSI effects using Opensees. Incremental Dynamic Analyses (IDAs) were employed to assess the seismic performance levels of SMRFs considering Near-Fault Pulse-Like (NF-PL) and Near-Fault No-Pulse (NF-NP) records suggested by FEMA-P695. The results showed that assuming semi-rigid connections with rigidity of 80%, 70%, and 60%, significantly decreased the median values of IDA curves compared to rigid connection. Considering the SSI effects can considerably decrease the Sa(T1) values of IDA curves and seismic collapse probability in all soil types; therefore, it is suggested to assume the real condition of the structure by modeling the connection rigidity and the SSI effects. It can be concluded that SMA bolts have the ability to improve the seismic performance of connection to compensate the lack of rigidity in semi-rigid connections of SMRFs; as well as, they can be used as a retrofitting strategy for existing buildings.

Behaviour of composite beam-column joint with fin plate connection subjected to impact loads

Falling-debris impact on a remaining building is detrimental and may lead to propagation of initial damage by abnormal loadings (gas, explosion, etc.), if the structure is not able to resist the impact. This in turn will lead to progressive collapse of the whole structure. For a frame structure, fin plate (or shear tab) connections ideal for gravity-dominant design is normally weaker than seismic connection. Therefore, its integrity under dynamic loading is of great importance for anti-progressive collapse performance. A series of tests on composite joints with fin plate connections subjected to impact loads was conducted to investigate the dynamic behaviour, which served as an unfavourable loading scenario for falling-debris impact which occurred close to the beam-to-column connection. Three middle joints and one side joint were designed and tested in the experimental programme. The test parameters included impact load, joint type and composite slab thickness. Structural response, failure mode and development of strains were investigated. A comparison of test results and design predictions of ultimate strength was conducted. The comparison was also extended to composite joints subjected to quasi-static loads. It was found that an intermediate level of strain rate in the order of 1 s−1 was recorded for the impact tests and it would lead to maximum increases of 28 % in concrete strength and 16 % in steel reinforcement strength, respectively. Compared to quasi-static tests, strain rate effect in the impact tests could increase compressive arch, catenary and flexural resistance of composite FP joints. Moreover, composite slab effect was beneficial to flexural resistance and detrimental to tying resistance, since deformation capacity of fin plate connection was consumed for flexural resistance at small deformation stage.

Numerical and Experimental Analysis of the Load-Carrying Capacity of a Timber Semi-Rigid Dowel-Type Connection.

The paper deals with the analysis of the load-carrying capacity of a timber semi-rigid connection created from a system of two stands and a rung. The connection was made from glued laminated timber with metal mechanical dowel-type fasteners. Not only a common combination of bolts and dowels, but also fully threaded screws were used for the connection. The aim of the research and its motivation was to replace these commonly used fasteners with more modern ones, to shorten and simplify the assembly time, and to improve the load-carrying capacity of this type of connection. Each of these two types of connections was loaded statically, with a slow increase in force until failure. The paper presents results of the experimental testing. Three specimens were made and tested for each type of the connection. Experimental results were subsequently compared with numerical models. The achieved results were also compared with the assumption according to the currently valid standard. The results indicate that a connection using fully threaded screws provides a better load-carrying capacity.

Development and behavior of a thin fitting connection for lamination with structural PVB

Intended for the construction of a double curved, frameless modular glass shell demonstrator, a stainless steel fitting connection with a trapezoidal, thin sheet laminated into the interstice of two-ply safety glass has been developed. For the bonding within the glass laminate, structural PVB interlayer is used. Various interlayer plies of different PVB types can be stacked depending on the necessary interstice thickness and the intended esthetical appearance. The fitting is designed to mainly transfer translational forces, but it also provides some bending stiffness via a crossbar supported against the glass edge. Various tests, including tension, shear and bending load application, have been performed at the Lucerne University of Applied Sciences and Arts (HSLU) to explore the structural behavior and the load bearing capacity of the fitting connection. In addition, parameter studies using finite element models were made to explore the influence of the fitting geometry, dimensions, interlayer properties and loading type on the structural behavior of this type of connection. These parameter studies and test results allow to identify further shape optimization and application possibilities of such thin, laminated fittings for load bearing glass structures.

Experimental Investigation into the Capacity of Concentrically Loaded Steel Connections with Pretensioned High-Strength Bolts and Longitudinal Fillet Welds in Combination

This paper presents the results of an experimental study aiming to investigate the behavior of steel connections that combine pretensioned high-strength bolts and longitudinal fillet welds on a common faying surface. A total of 75 double-shear tension splices were tested under direct tension loading to quantify the effect of various connection variables on the load-deformation behavior of the connection. These variables include the (1) bolt pattern (2×2 and 2×3), (2) bolt size (3/4 in. and 1 in.), (3) bolt grade (ASTM F3125 Grade A325, A490, and F1852), (4) bolt pretensioning method (turn-of-nut and tension control bolts), (5) faying surface class (Class A and B), and (6) weld/bolt strength ratio. The variation in the connection characteristics covered a wide range of weld/bolt strength ratios from 0.50 to 2.00. The bolts were installed in oversized holes, and the specimens were assembled in a negative bearing condition to allow for a maximum slip distance. The load-deformation behavior of the combination connections was recorded and compared to that of the bolted- and welded-only control specimens. In all tests, the addition of welds increased the capacity of the connection. The investigation shows that the capacity of the combination connection with pretensioned high-strength bolts and longitudinal fillet welds can be computed by adding the capacities of the individual connecting elements while considering the strain compatibility.

Behaviour and Design of Bolt-Coupler Connections under Compression in Prefabricated CFST Columns

The paper presents the investigated results of bolt-coupler connections under compression experimentally. Bolt-coupler connections have been developed recently for prefabricated column-to-column (PCC) connections to simplify the construction process of prefabricated concrete-filled steel tubular (CFST) columns and to transfer the upper column load to the bottom column through bolt-coupler connections. However, the behaviour of bolt-coupler connections under compression has not been investigated in the past although there are some experimental and numerical studies conducted on bolt-coupler connections under tension. To address these research gaps, the behaviour of bolt-coupler connections under compression has been investigated. The main parameters considered in this study are bolt diameters (M16, M20, M24), bolt grades (8.8, 10.9 grade), gap inside the coupler between two bolts of bolt-coupler connection (0, 10, 20 mm), and coupler grade (5.6, 8.8 grade). It is observed that the ultimate capacity of bolt-coupler connections is reduced significantly with an increase in the bolt gap inside the coupler of the bolt-coupler connection. Based on the test data, a design equation is developed to determine the design capacity of bolt-coupler connections under compression, which will be very useful in designing the PCC connections of sustainable prefabricated CFST columns.

Design of Power Location Coefficient System for 6G Downlink Cooperative NOMA Network

Cooperative non-orthogonal multiple access (NOMA) is a technology that addresses many challenges in future wireless generation networks by delivering a large amount of connectivity and huge system capacity. The aim of this paper is to design the varied distances and power location coefficients for far users. In addition, this paper aims to evaluate the outage probability (OP) performance against a signal-to-noise ratio (SNR) for a 6G downlink (DL) NOMA power domain (PD) and DL cooperative NOMA PD networks. We combine a DL cooperative NOMA with a 16 × 16, a 32 × 23, and a 64 × 64 multiple-input multiple-output (MIMO) and a 128 × 128, a 256 × 256, and a 512 × 512 massive MIMO in an innovative method to enhance OP performance rate and mitigate the power location coefficient’s effect for remote users. The results were obtained from Rayleigh fading channels using the MATLAB simulation software program. According to the outcomes, increasing the power location coefficients for the far user from 0.6 to 0.8 reduces the OP rate because increasing the power location coefficient for the far user decreases the power location coefficient for the near user, which results in less interference between them. In terms of the OP performance rate, the DL cooperative NOMA outperforms the NOMA. According to the findings, the DL cooperative NOMA OP rate outperforms the DL NOMA by a rate of 10−0.5. Whereas the 16 × 16 MIMO enhances the OP for the far user by 78.0 × 10−4, the 32 × 32 MIMO increases the OP for the far user by 19.0 × 10−4, and the 64 × 64 MIMO decreases the OP rate for the far user by 5.0 × 10−5. At a SNR of 10 dB, the 128 × 128 massive MIMO improves the OP for the far user by 1.0 × 10−5. The 256 × 256 massive MIMO decreases the OP for the far user by 43.0 × 10−5, and the 512 × 512 massive MIMO enhances the OP for the far user by 8.0 × 10−6. The MIMO techniques improve the OP performance, while the massive MIMO technology enhances the OP performance dramatically.

Experiments on cyclic behaviour of cold-formed steel-rubberised concrete semi-rigid moment-resisting connections

This paper presents the results of full-scale physical tests on a recently developed cold-formed steel (CFS) semi-rigid moment-resisting connection infilled with rubberised concrete (RuC) for seismic application. The connection comprises side-plates attached to both sides of built-up tubular CFS beam and column sections through either screwed or welded connections. The tests were performed on both bare steel and CFS-RuC composite connections under cyclic loading for comparison purposes. The predominant modes of failure are beam local buckling and side plate plasticity in the bare steel connections and screw shear failure in the composite connections. The results show that the composite connection typically reaches 45% higher strength and 21% greater energy dissipation capacity than the bare steel connection both having 24 screw arrays. These indicate the beneficial effects of the infill RuC in prevention of the beam local buckling in connections with identical connection configuration. The energy dissipation capacity of the bare steel connection having 36 screw arrays, however, was 70% greater than that of the composite connection with 24 screw arrays. This reflects side plate plasticity being a more effective energy dissipation mechanism than the other identified mechanisms.

A study of hybrid self-centring beam-to-beam connections equipped with shape-memory-alloy-plates and washers

This paper examined the hysteretic performance of a novel hybrid self-centring beam-to-beam connection equipped with shape memory alloy (SMA) plates and SMA Belleville washers. An experimental programme employing three proof-of-concept test specimens with varied SMA plate geometries and connection configurations was conducted. The test connections showed recentring performance with controllable residual deformations. The encouraging energy dissipation capacity of the test connections accompanied by excellent ductility was also confirmed. Subsequently, a numerical study was carried out to help interpret the test results and to further examine the connection's load carrying mechanism. In the numerical work, a hybrid finite element (FE) modelling technique enabling reproducing the residual strain development of SMA plates under hysteretic loading was developed and verified. The test and numerical study showed that the self-centring ability of the connection was appreciably affected by the hysteretic behaviour of SMA plates. The FE results also confirmed that the connection behaviour was sensitive to the connection configuration, and a minor gap between the beam segments could initiate intense buckling of the SMA plates. Nevertheless, the lateral deflection of the SMA plates can be suppressed by effective buckling restraints. To facilitate practical application, a theoretical prediction model enabling the quantification of a bilinear skeleton response of the connection was proposed, and the adequacy of the prediction model was evidenced by the correlation among the results of the tests, FE simulations and design predictions.

On the Seismic Evaluation of Steel Frames Laterally Braced with Perforated Steel Plate Shear Walls Considering Semi-Rigid Connections

Steel plate shear walls usually do not satisfy the strong-column weak-beam design criteria, leading to larger column sections. On the other hand, rigid frame structures are typically constructed in low-rise to mid-rise buildings built in locations prone to strong earthquakes due to their high flexibility and cost-effective solutions. Overcoming these restrictions to the SPSW system, this paper is dedicated to employing a semi-rigid connection that dissipates energy well and reduces the forces applied to the structure. By using a semi-rigid connection in an adjacent span to the SPSW, the actual flexural capacity of the beam end decreases and, subsequently, improves the performance of the structure in terms of the of the strong-column weak-beam criteria. Thereupon, the impact of the semi-rigid connections on steel frames with SPSWs as a sideway resisting system can be assessed by implementing a numerical study. In this paper, a new methodology for modelling semi-rigid joints is used considering five connections with different moment capacities. Moreover, the influence of three different circular diameters on the behavior of the perforated SPSWs was investigated. To fulfil these purposes, nonlinear dynamic analysis was conducted to assess the reliability of 5-, 10-, and 15-story frames resisted with SPSWs and semi-rigid connections subjected to actual ground motion records. A total of 45 frames were modelled and the obtained results were compared with reference benchmarks. The outcomes of the studies show good agreement with design building code requirements. In addition, the reliable performance of the structure under seismic loads is evaluated. According to the results of the parametric study, the presumed allowable drift leads to obtaining the optimum moment capacity of connection for each model and illustrates the applicability of a new structural system consisting of SPSWs and semi-rigid connections simultaneously.

Seismic behavior of exterior-diaphragm CFSST connections with or without PBL

The exterior-diaphragm connection to concrete-filled square steel tubular columns with perfobond ribs (i.e., exterior-diaphragm CFSST connection with PBL) is an innovative connection formed by arranging PBL in steel tube of the small-sized-exterior-diaphragm CFSST connection. To explore the seismic behavior of this type of connection, cyclic tests of exterior-diaphragm connections with or without PBL were carried out. The failure modes, P-Δ hysteretic curves, stiffness degradation, energy dissipation capacity, shear deformation of joint region, strain distribution in diaphragm and panel zone of different specimens were compared and analyzed. On this basis, the tensile force transfer paths in different connections were compared by FE numerical simulation quantitatively. It is found that PBL carry a considerable portion of the tensile forces from steel beam flanges and transmit them to core concrete in joint regions, and enable the core concrete to participate in tensile load transferring and then in horizontal shear resisting of the novel connections, which greatly alleviates the stress concentrating at corners of steel tubes and exterior-diaphragm, and decreases the shear deformation and strain in joint regions. So, the stiffness, ductility, load carrying and energy dissipating capacity of exterior-diaphragm connections with PBL are improved a lot. Higher axial load level reduces the shear stiffness and strength of concrete dowels, and then deteriorates the stiffness degradation, energy dissipation capacity and shear deformation of panel zone. Even if the dimension of exterior-diaphragm is much smaller than that specified in codes, the innovative connections under common and high axial load level have good seismic behavior and fail as the yielding of steel beam flanges without obvious damage in exterior-diaphragm and steel tubes.

Series Structure of a New Superconducting Energy Storage

For some energy storage devices, an efficient connection structure is important for practical applications. Recently, we proposed a new kind of energy storage composed of a superconductor coil and permanent magnets. Our previous studies demonstrated that energy storage could achieve mechanical → electromagnetic → mechanical energy conversion with high efficiency and low loss. Additionally, we have found an optimized configuration of magnets to increase the capacity of the energy storage/conversion device. This article discusses a series connection structure to further enhance the capacity of the energy storage device. Two sets of experiments were carried out to investigate the effectiveness of the connection structure. The experimental results indicate that the energy capacity of a series connection of two such storage units will be the sum of the two units. The energy conversion efficiency is not compromised in the connection structure. Based on the results, it was concluded that an energy storage array with a much larger capacity may be achievable by a proper serial and parallel arrangement of multiple such energy storage/conversion units.

A Review of Chandran Nair's Dismantling Global White Privilege: Equity for a Post-Western World

A Review of Chandran Nair's Dismantling Global White Privilege: Equity for a Post-Western World Rachel Li (bio) The contemporary has experienced humanity's increased capacity for connection across geographical boundaries. For many, the potential for instantaneous proliferation of ideas around the globe was exemplified by the U.S. Black Lives Matter protests of 2020, which were followed by numerous protests in other countries that called into questioned the systems perpetuating racism and discrimination against marginalized groups.1 However, fully understanding the universal effects of White privilege also requires understanding the interconnections between White privilege and conceptions of Western superiority on a global scale. In his book Dismantling Global White Privilege: Equity for a Post-Western World, author Chandran Nair aims to explain the perpetuation of hegemonic Western culture that imposes economic supremacy through the lens of white privilege. Nair details four main patterns that reinforce white privilege: (1) The "ideal" form of different spheres of life (including politics, economics, and aspects of culture) follows a Western model; (2) White and Western entities give legitimacy to certain expressions or actions through a reliance on Western terms of reference; (3) Institutions that judge how closely others follow such standards are largely Western and white-led; (4) Only White and Western entities in power are able to punish those who go against their established global order.2 By examining these patterns in cases ranging from politics and economics to culture and education, Nair seeks to illuminate the subtle yet destructive ways white privilege and Western dominance have been enforced through global systems. Though the author recognizes different readers will likely have very different reactions to the book, Nair centers his book on raising awareness to spark further conversation. Privileged politics Nair begins his book by calling into question the notion of Great Power Competition that frames much of the U.S.-led Western discourse on current international affairs. Rather than seeing global politics through the lens of national security or the preservation and promotion of democracy, Nair argues that Western dominance on the global stage and within international institutions is the foundation for the overarching status quo. Within fundamental understandings of the world order in recent decades, Nair emphasizes a stark contrast between the mainstream narratives of relative peace worldwide and the harsh realities of hundreds of armed conflicts taking place in Asia, Africa, and Latin America since the end of World War II.3 Nair then outlines various ways that white privilege and Western superiority have contributed to global disparities while passing the blame and burden to improve onto non-Western countries. In one example, the author references the long-held standard of the World Bank being led by an American and the International Monetary Fund (IMF) by a European. The IMF Articles of Agreement specifically set the voting rules for the organization's director, granting countries with the largest economies and economic viability preference for membership onto the executive board. The executive board—largely from white, West European nation-states—then [End Page 277] appoint the director.4 As for the World Bank, the United States supposedly seemed the least scathed by the war and thus most able to lead an organization aimed at rebuilding a post-World War II Europe.5 These examples demonstrate that Western dominance is deeply ingrained in our world order, and the world order is rooted in centuries of Western imperialist economic success. Furthermore, the World Bank, originally named the International Bank for Reconstruction and Development, was created for the purpose of giving financial support to Western countries, yet it adopted a global name to symbolize trans-Atlantic relations between the United States and Europe.6 This image of international cooperation solely based in the West neglects whole continents that not only also suffered heavy losses from war, but also suffered centuries of exploitation at the hands of white colonial powers. Nair recognizes that no country has perfectly protected its people and supported its economy at all times. However, he makes it clear that the West has repeatedly overlooked acts of "authoritarianism, corruption, and other human rights abuses" in the past, as long as the countries in which these acts were committed are perceived...

“We could have been leaders”: The rise and fall of offshore wind energy on the political agenda in Ireland

Many countries have ambitious plans for increasing the generation of electricity from offshore wind energy in the coming decades. Realising these ambitions requires concerted, often innovative, political action across several policy domains. To understand the unique political challenges facing offshore wind deployment, this article presents a case study of the Republic of Ireland, where decades of sporadic political ambition to support offshore wind energy has not yet translated into commercial deployment. We use the Multiple Streams Framework to guide data collection, 29 elite interviews and extensive documentary analysis, and offer an historical explanation for why political actors did not meet long-standing market ambition. We analyse the battle of ideas between alternative policy approaches that emerge through distinct policy networks and institutions spanning marine planning, grid development, and energy price support. In Ireland, two key drivers restrained political support for offshore wind for over a decade: competition with onshore wind for limited grid connection capacity and resilience, and calibration of policy instruments to attain decadal renewable energy target at least cost. The study shows the value of a deviant case to demonstrate the political complexities of developing and adopting technology-specific policy instruments to support offshore wind energy in the context of long-term climate change targets, grid development, and grid system services plans.

5G in agri-food - A review on current status, opportunities and challenges

Autonomous tractors, spraying drones, robotics and fully autonomous farms are possible outcomes of the digital transformation trend in agriculture and food systems which is fostered by continuous technological advancement and the increasing connectivity capacity. These futuristic scenarios will be unlocked by 5G connectivity, the next step after 4G, because it enables high data transfer volumes and low latency which can lead to many beneficial outcomes for technology applications in agri-food, such as Internet of Things (IoT) and Blockchain. Considerable progress is seen in the 5G ecosystem around the world, from South Korea to Australia and Europe. This review presents the opportunities and challenges of 5G in agri-food. The six most compelling use cases of 5G in agri-food at this moment from different parts of the world are in Brazil, the Netherlands, South Korea and the United Kingdom. The future of 5G in agri-food will depend on a number of enabling factors including interoperability, data governance and security, new business models, policy changes, and innovative ecosystems. The baseline scenario of connectivity and infrastructure for a region or country is determined by the dimensions of 5G aggregation-, cyber physical management- and decision-making levels, which guide future 5G applications in agri-food. Agriculture technology collaboration across the private and public sector and ecosystem development are the first steps for all countries to make progress towards large scale uptake of 5G in agri-food.

Shear behavior of stainless-steel plate connectors for insulated precast concrete sandwich panels

In this study, 24 double-shear tests were performed on precast concrete insulated sandwich panels using stainless-steel plate connectors. Parameters in the test program included connector shear directions (in-plane/out-of-plane), presence of insulation (with/without), cavity widths (30 mm/80 mm/120 mm) and connector heights (120 mm/160 mm). In order to test the pure shear capacity of connectors, the insulation was removed in the in-plane shear tests. The test results indicated that the connectors with 80 mm and 120 mm cavity width failed by shear buckling and the connectors with a cavity width of 30 mm were pulled out after buckling when subjected to in-plane shear. For the out-of-plane shear tests, bending of connectors occurred in the specimens without insulation, and connectors were pulled out in the specimens with insulation. For in-plane shear connectors with cavity widths of 30 mm, 80 mm and 120 mm, the shear capacities of 120 mm high connectors were 31.8 kN, 25.8 kN and 11.5 kN respectively, while the shear capacities of connectors with a height of 160 mm were 49.3 kN, 30.2 kN and 17.6 kN. The shear capacities of the out-of-plane connectors was only 3.7% of the in-plane connectors. It was also indicated that the presence of insulation significantly contributed to shear transfer in out-of-plane shear tests, leading to 28.6 times higher shear capacity than the specimens without insulation. Based on Basler's tension field theory, an analytical model was developed to predict the shear capacity of plate connectors. Compared with test results in this paper and other studies, the predictions were in good agreement.

Experimental and numerical study of a novel cold-formed steel T-Stub connection subjected to tension force

Cold-formed steel (CFS) is a popular form of construction in New Zealand and the developed world because it can be cost-effective, durable, sustainable, resilient to extreme environmental and seismic loads and easy to install. When used in domestic and medium-rise buildings, T-Stub connection between CFS channel sections is formed by using self-drilling screws which connect the flanges. In the literature, no prior investigation on the tension capacity of such connection has been reported. Therefore, this paper describes a novel test procedure for determining the tension capacity of such CFS T-Stub connection and the associated mechanism of failure. An experimental test program that comprises thirty experimental tests is reported in this paper. Three channel section thicknesses were examined: 0.55 mm, 0.75 mm, and 0.95 mm. All specimens failed as a result of tilting of the screws and bearing failure. Non-linear elasto-plastic finite element (FE) models were developed, and the predictions were validated against the experimental test results. It was adjudged that there was reasonable agreement in terms of connection strength and failure mode prediction. Finally, the design strengths derived from current design standards were compared with the experimental failure loads. It was found that the American Iron and Steel Institute (AISI 2016) and Australian and New Zealand Standard (AS/NZS 2018) are conservative by 6% and unconservative by 10% for the initial and final failure loads of T-Stub CFS connections, respectively.

Assessing the feasibility of a migration policy from LPG cookers to induction cookers to reduce LPG subsidies

Several developing countries have attempted to reduce liquefied petroleum gas (LPG) imports and subsidies by shifting from the use of LPG to electric stoves. In Indonesia, the LPG subsidy reached US$ 4.9 billion and LPG imports increased to 6.3 million tonnes in 2021. Our study aims to analyse the feasibility of an induction cooker program in Indonesia to reduce LPG subsidies. Firstly, we calculated the energy equivalent factor of the induction cooker compared to the LPG cooker. Subsequently, we surveyed 1006 respondents with different electricity connection capacities regarding their monthly LPG consumption and perceptions of induction cookers. We found monthly electricity consumption for the induction cooker to be around 62 kWh to 235 kWh, depending on the customer group. Cooking with the induction cooker has a lower energy cost compared to cooking with the unsubsidised 12 kg LPG cylinder. However, for customers previously using the subsidised 3 kg LPG cylinder, the induction cooker program only reduces energy costs for cooking for the 450 VA customers. The LPG subsidy saving can compensate for the capital costs of switching to induction cooking within three years. Several policy recommendations are discussed based on these findings.

Bending and tensile stressing state features of ductile iron pipe flange connections revealed from tested strain data

The existing theories and methods based on structural ultimate working states with empirical judgment could not estimate the load-bearing capacity of ductile iron pipe flange (DIPF) connections accurately. This paper tries to address the issue applying the novel structural stressing state theory and methods, leading to the revelation of the essential bending and tensile working features of DIPF connections. Firstly, the experimental strain data are transformed into the generalized strain energy density (GSED) values to build the stressing state modes and the characteristic parameters. Then, the Mann-Kendall criterion is adopted to detect the mutation points in the evolution curves of characteristic parameters. Correspondingly, it is verified that the evolutions of stressing state modes also present the mutation features. The mutation features are the embodiment of the natural law from quantitative change to qualitative change of a system, which defines the starting points of DIPF connections’ failure processes. Furthermore, the Mann-Kendall criterion distinguishes the elastoplastic branch (EPB) points in the stressing state evolutions of DIPF connections. Both failure starting points and EPB points provide the new foundation to accurately determine the working capacities of DIPF connections and to improve their design.

Improving the Dynamic Competitiveness of Enterprises: Research in the Field of Tourism

Enterprises are now facing fierce competition under the pressure of global economic integration. For sustainable development, businesses must improve their competitiveness. In that context, identifying, nurturing, and developing resources to increase competitiveness is an urgent requirement of enterprises. The article focuses on determining factors affecting dynamic competitiveness. Empirical research in the field of tourism has shown that absorptive capacity, adaptive capacity, creative capacity, connectivity capacity, cognitive capacity, and market orientation are the basic components of tourism competence dynamic competition. The article suggests implications for building and improving the dynamic competitiveness of enterprises.