Service Load Research Articles

A Cloud Monitor to Reduce Energy Consumption With Constrained Optimization of Server Loads

A Cloud Monitor to Reduce Energy Consumption With Constrained Optimization of Server Loads

Influence of Service Load and Structural Parameters on Optical Accuracy of Solar Tower Heliostat

Influence of Service Load and Structural Parameters on Optical Accuracy of Solar Tower Heliostat

Review on rehabilitation of rc deep beams using external bonded frp and nsm technique

Due to a variety of reasons, including increased service loads, environmental impacts, construction errors, and mechanical impediments, the strengthening process was becoming necessary for many concrete buildings worldwide. The strengthening process is carried out in several ways, the most common of which are the Near-Surface mounted (NSM) technique and the External Bonded Reinforcement (EBR) technique. The main object of the strengthening process is to increase the strength and durability of reinforced concrete structures and reducing early failure. This research discussed the most important papers that dealt with strengthening deep beams due to their exposure to heat or extreme loads using two techniques (NSM) and (EBR). Several results were reached through experimental testing of the specimens of each research, especially the most important of them: First, making openings, when necessary, away from the loading path because the opening in the loading path reduces the capacity of the beam. Secondly, resorting to using the mechanical method when installing the fiber-reinforced polymer externally, as it greatly reduces the tearing and collapse of the sheets. Third, the number of layers must be less than three when using (GFRP) sheets in the strengthening process, as violating this will cause a decrease in the final capacity of the beam. Fourth, resorting to inclined schemes when strengthening deep beams or repairing them with various materials made of carbon fiber-reinforced polymer (FRP). Finally, it is possible to use (CFRP) bars with (NSM) technology, as this option can be relied upon to rehabilitate damaged structures.

Steel Structures Research Update: Adhesive Steel-to-Steel Connections

Ongoing research on adhesive steel-to-steel connections is highlighted. This study, currently underway at the University of Massachusetts–Amherst, is led by Dr. Kara Peterman, Associate Professor in the Department of Civil and Environmental Engineering. Dr. Peterman’s research interests include behavior of cold-formed and hot-rolled steel structures under service loads and extreme loads due to natural hazards. Among Dr. Peterman’s accolades for her teaching and research are the University of Massachusetts–Amherst College of Engineering Outstanding Teacher Award, the McGuire Award for Junior Researchers from the Structural Stability Research Council (SSRC), the AISC Terry Peshia Early Career Faculty Award, and the AISC Milek Fellowship. The four-year Milek Fellowship is supporting this research on the holistic design and behavior of adhesive steel-to-steel connections. The research team is partway through year two of the four-year study. Selected highlights from the work to date are presented, along with a preview of future research tasks.

HEALTH PRESERVATION OF SUBJECTS AS THE BASIS AND GOAL OF THE MANAGEMENT ACTIVITIES OF THE COMMANDERS OF THE RUSSIAN NATIONAL GUARD TROOPS (EXPERIMENTAL STUDY)

Background. The work of the commanders of units of the National Guard Troops, aimed at protecting the health of their subordinates, acts as one of the most important components of the management activities of the commanders of the National Guard Troops of the Russian Federation. The results of the effectiveness of the work of the commanders of units for the protection of the health of subordinates of the Faculty of Special Forces of the Novosibirsk Military Institute of the VNG of the Russian Federation were studied and summarized. The focus on the health protection of subordinates lies in the fact that this is primarily associated with the performance of labor-intensive and specific functions by subordinates, and their performance in daily life of a wide range of tasks, as well as an increase in the service and combat load. The list of tasks assigned to the troops of the National Guard of the Russian Federation is determined by its diversity, and requires adequate management of subordinates at all its levels. The variety of tasks performed by servicemen (employees) implies possible deviations in professional behavior, as well as a weakening of physical abilities that they cannot always cope with on their own, which is why a serviceman, as a subject of health conservation, requires a special approach and study.
 Materials and methods. The questionnaire method was used as a method of collecting empirical data. In total, 90 commanders of units of different levels of the Faculty of Special Forces of the Novosibirsk Military Institute named after General of the Army I.K. Yakovlev of the National Guard Troops.
 Results. The study showed the leading role of unit commanders in the work of saving and maintaining the health of subordinates in the framework of managerial activities. It is assumed that the formed managerial competencies of commanders directly affect the level of safety and health promotion of subordinate military personnel.
 Conclusion. The existing system of health saving in the troops of the National Guard of the Russian Federation has specifics and determines the features of the formation of health-saving behavior of military personnel, reflecting the requirements of the military organization and characterized by a system of values, norms and attitudes. The conclusion is made about the presence of objective problems in the knowledge of the theoretical aspects by the commanders of subdivisions (mainly junior command level) of the legal framework of labor protection.

Development of computer application system and database testing based on data encryption technology

Abstract In this paper, we use the MapReduce programming framework for the development of a computer application system and design the vision module, control module and transaction module of the system based on MVC architecture. Focusing on the encryption design of the database, the data stored in the database is chunked through the Map function, and all the chunking results are aggregated based on the Reduce function, and synchronized encryption of the database is combined with the Paillier homomorphic encryption algorithm. On this basis, the system environment is configured, and the application system developed in this paper is tested, focusing on exploring the stability of the database. The test results show that the decryption output time is 21s when the Paillier encryption algorithm is 200, and the first set of database peak is 76% of the server load, which is within the tolerable range. Security test on the database: the results show that the probability of an attack on all ports with a database security factor less than 6 is around 0.3. There is no significant difference, and the database test is good.

A limit analysis approach to uplift bearing capacity of shallow plate anchors in marine environments

AbstractOffshore oil and gas exploration activities involve the installation of various subsea infrastructures on the ocean floor, often supported by shallow foundations such as anchor plates or mudmats. These foundations must be designed to withstand applied service loads along the structure lifecycle, including decommissioning loads required for subsequent removal. In this context, this work is dedicated to the evaluation of uplift bearing capacity of shallow anchors within the theoretical framework of limit analysis and its related kinematic approach. Based on the implementation of 3D failure mechanisms, rigorous upper bound estimates for the uplift force viewed as ultimate load for the material system are derived from either total or effective stress analyses. In that respect, emphasis is given to the formulation of limit analysis problem in the context of effective stresses, showing how the effect of seepage flow may be accounted for by means of driving body forces derived from the gradient of excess pore pressure distribution and how suction forces arise from pore pressure difference between upper and lower anchor surfaces. Evaluation of suction forces developed during anchor lifting is addressed by resorting to a simplified modeling applied to circular and rectangular anchors. The accuracy of the upper bound predictions derived for uplift force is assessed by comparison with available experimental data. Several numerical results are also provided to investigate the effects of relevant problem parameters on the uplift bearing capacity.

Surrogate-Based Calculation Method for Robust Design Optimization Considering the Fatigue Probability for Variable Service Loads of eBike Drive Units

This paper proposes a robust design-optimization approach for eBike drive units that incorporates the highly variable driver-dependent load collectives and system conditions into a fatigue calculation. In an initial step, the relevant influences and loads on the investigated system are examined and reviewed in relation to the current normative requirements. From a methodical viewpoint, this paper presents a surrogate-based simulation-based approach to assess reliability across the entire geometry according to a probabilistic fatigue calculation. The probabilistic evaluation considers the several measured load collectives of different drivers and driving scenarios to enable a robust and type-oriented bike design. In addition to methods of fatigue calculation, this approach also includes common methods of order reduction and reliability-based design optimization. To avoid additional uncertainties in the calculation, this approach considers a complex critical-plane-based multiaxial-fatigue calculation to correctly evaluate the multiaxial and non-proportional stress state across the whole geometry. A data-based surrogate model that supports the fatigue calculation by predicting the load across the given uncertainties is the key to the efficient assessment of the service life of the eBike. Lastly, the identified uncertainties in the design of eBike drive units are investigated and evaluated by this method.

Flexural behavior of GFRP-RC beams confined with CFRP in compression zone

In this study, the CFRP sheets and CFRP stirrups are employed to confine the compression zone in GFRP-reinforced concrete (GFRP-RC) beams to improve the ductility of the beams. Four-point bending tests are conducted on four CFRP sheets and six CFRP stirrups confined GFRP-RC beams. The cracking bending moment, crack width, mid-span deflection, bearing capacity, and ductility of all the beams are analyzed. Results show that the effect of the confinement in the compression zone on the cracking bending moment and crack width under service load can be ignored. The cracking bending moment can be accurately estimated using ACI 440.11–22, while the GB50608–2020 standard provides an accurate prediction for the crack width under service load. The GFRP-RC beams confined with CFRP stirrups exhibit mid-span deflections reaching up to 95 mm prior to failure. In addition, the CFRP stirrups confinement is more effective compared to CFRP sheets confinement due to the poor bond performance between the CFRP sheet and concrete. Furthermore, an accurate equation for the calculation of bearing capacities of GFRP-RC beams confined with CFRP sheets and stirrups has been proposed. It has also been demonstrated by this study that significant improvements in the ductility of GFRP-RC beams can be achieved by confining the compression zone. Deformation ductility factors of all the beams are analyzed to support this conclusion.

Battery Energy Storage System for Building Integrated Photovoltaic Applications

Human pursuits’ daily energy needs are consistent; however, renewable energy sources are intermittent in nature. Thus, an energy storage system is required to bridge the generation-demand gap. Electrical energy storage (EES) is a system that converts electrical energy into a form that can be easily stored in various devices and converted back into electrical energy as needed. The battery energy storage system (BESS) is one of the most well-known and promising EES technologies for storing renewable energy. Today, various BESS types are in use; some are established technology, while others are still in R&D. The selection of BESS capacity for building integrated photovoltaic (BIPV) systems necessitates a trade-off between critical criteria, including power vs. energy, design voltage, and operating temperature. This research analyzed various BESS technologies and presented optimal capacity selection and design criteria. Hence, the best BESS design approach takes into account climatic data, PV panel specifications, and budget constraints. While BESS technology varies depending on project requirements and other considerations, lithium-ion batteries are the most commonly used due to their high energy density, efficiency, and extended cycle life. For cost-sensitive BIPV systems, lead-acid batteries are preferred due to their low capital cost, technological maturity, and relatively good cycle efficiency. Thus, the correct quantity of batteries in a BESS bank is determined by energy storage goals, BESS type and size, and service load. Finally, the paper concluded with recommendations for best practices for BESS design, appropriate operation, and maintenance conditions for Nigeria’s prevalent BESS technology for BIPV applications

DCSP: A delay and cost-aware service placement and load distribution algorithm for IoT-based fog networks

The service placement problem in a fog-cloud pertains to the intricate task of ascertaining the optimal placement locations for diverse service replicas that constitute an Internet of Things (IoT) application within a distributed computing architecture. Nonetheless, due to the heterogeneous nature of fog nodes and cloud data centers, the constantly evolving nature of IoT applications, the pressing demand for real-time data processing with minimal latency, and the imperative of cost optimization, service placement remains an arduous and intricate challenge. Heuristic algorithms are widely employed to derive near-optimal solutions. The present study introduces a novel heuristic approach to service placement and load distribution in fog-cloud environments called Delay and Cost-aware Service Placement (DCSP). This approach takes into account both delay and cost and thereby enables the optimal utilization of resources, delay, and cost for delay-sensitive services. DCSP features continual adjustment of the number of service replicas based on workload and resource availability, ensuring efficient usage of fog and cloud computing resources and optimal delay for each request. The results of simulation experiments that compare various algorithms demonstrate the superiority of DCSP, which outperforms other methods in cost, average delay, and resource utilization. The experimental results not only illustrate the exceptional superiority of our method over MOHGA, MVC, and the Local method in terms of delay and utilization but also demonstrate our efforts to maintain cost at a comparable level. Our method surpasses all of them in utilization, achieving remarkable improvements ranging from 7.4 % to 49.7 %. Furthermore, it outperforms them in terms of delay, with significant enhancements ranging from 2.1 % to 19.3 %.

Reversed audio file content subset identification over existing files using the deduplication technique

The prevalence of cloud storage among users has surged, yet it's imperative to maintain server efficiency as data volume grows. Repositories are brimming with repetitive content, while users continue to demand consistent daily performance despite the extensive storage capacity. Service providers, however, cannot restrict users from uploading multimedia files that already exist on the server. This poses a challenge for storage administrators striving to enhance services and pinpoint duplicate files. Deduplication emerges as a viable solution to alleviate the server's load. This study proposes a method to identify redundant audio content and reversed audio files within existing data, as well as detect reversed audio content. These efforts augment the existing, refined super set identification algorithm.

Extrapolation of real service loads to longer periods

Extrapolation of real service loads to longer periods

Experimental study on flexural behaviors of FRP and steel bars hybrid reinforced concrete beams

To investigate the flexural behaviors of Fiber-reinforced polymer (FRP) and steel bars hybrid reinforced concrete (Hybrid-RC) beams, twelve beams were designed and manufactured, including one steel bars reinforced concrete (Steel-RC) beam, one GFRP reinforced concrete (GFRP-RC) beam, and ten Hybrid-RC beams. The effects of FRP bars type, concrete strength, and effective reinforcement ratio on the flexural behaviors of Hybrid-RC beams were studied through experiments and compared with the predicted results of theoretical models. The research results indicated that when the reinforcement area and service load were the same, the crack width, deflection, ultimate bearing capacity, and ductility of Hybrid-RC beams were between Steel-RC and GFRP-RC beam. The flexural bearing capacity of Hybrid-RC beams might also be increased by using FRP bars with a higher elastic modulus or by increasing the effective reinforcement ratio; however, it would reduce the ductility of the beams. In contrast, increasing the concrete strength could simultaneously increase the Hybrid-RC beams’ flexural bearing capacity and ductility. The equation for calculating the stress of FRP bars in the ultimate state of Hybrid-RC beams was obtained by fitting regression based on the test results, and the equation’s predicted results and test results showed good agreement. In addition, the predicted results of the flexural behaviors of Hybrid-RC beams using the theoretical model agreed with the experimental results.

Thermo-mechanical fatigue deformation and fracture mechanisms of nickel-based powder metallurgy superalloy

Thermo-mechanical fatigue (TMF) failure is one of the major concerns for aero-engine turbine discs under complex service loading conditions. By conducting both in-phase (IP) and out-of-phase (OP) TMF tests, the stress-strain hysteresis loops and the cyclic stress responses were analyzed for the third-generation nickel-based powder metallurgy (P/M) superalloy FGH4098. To reveal the failure mechanism, advanced microscopy analysis was carried out to characterize the fracture surface and microstructure of the alloy after failure. The phase angle between alternating mechanical and thermal loads plays an important role for the magnitude and evolution of mean stress. According to SEM fractography, the crack growth exhibits intergranular fracture under IP TMF and transgranular fracture under OP TMF. From the electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) characterization results, the geometrically necessary dislocation (GND) density is higher for IP TMF, indicating more severe plastic deformation. The material shows cyclic softening in the high-temperature half-cycle, but cyclic hardening in the low-temperature half-cycle. The cyclic deformation is mainly related to dislocation activities under IP loading conditions, for which fatigue damage dominates the failure process. Under OP loading conditions, the deformation behavior is mainly associated with the generation of stacking faults (SF), and its failure mechanism includes both fatigue and oxidation damage.

An experimental study on hybrid fibre reinforced engineered cementitious composite link slabs under static and fatigue loadings

This study conducted experimental investigations on the structural performances of link slabs which are constructed by using a newly developed hybrid-fibre reinforced engineered cementitious composite (hybrid-ECC). Both static and fatigue loadings were applied to validate the feasibility, provide a proof of concept study and demonstrate the benefits using hybrid-ECC for bridge link slabs application. Three identical quarter-scaled hybrid-ECC link slabs, simulating a link slab used for a typical 35-meter multi-span simply supported bridge, were fabricated. These slabs, denoted as LS-1, LS-2 and LS-3, were tested under designated static and fatigue loadings. Slab LS-1 was tested under static loading to obtain the flexural strength of the slab. Slabs LS-2 and LS-3 were tested under fatigue loadings to evaluate their fatigue performances under normal service loading and overload scenarios, respectively. Structural performances of these slabs in terms of deformation and crack width control capability, strain development on reinforcement bars and estimated service life were evaluated. It was observed that multiple microcracks were developed under both static and fatigue loadings. Slab LS-2 survived ten million cycles of service fatigue loading while LS-3 survived two million cycles of overload fatigue loading. For all the tests conducted under static and fatigue loadings, the maximum crack width observed on the three link slab samples was all controlled within the allowable limit of 0.2 mm until failure occurred. Based on the test results, it was estimated that if only the effects due to normal traffic loading and temperature variation were considered, the hybrid-ECC link slab could achieve a service life of more than 40 years. Therefore, the experimental study reconfirmed that the hybrid-ECC showed a high potential to improve the fatigue performance and extend the service life of link slab in bridge construction.

Fatigue Damage of Short Fibre-Reinforced Thermoplastics in Crashworthiness Simulation

Service loads repeatedly stress components on a regular basis and lead to fatigue damage in the material. In the case of components made of short fibre-reinforced thermoplastics, which are also crash-relevant in addition to only bearing service loads, however, a significant deterioration in mechanical properties can be observed after fatigue damage has been introduced. This is where the approach presented in this paper comes in: in order to enable a realistic simulation of such components in their used conditions, the material data are assigned depending on previously determined damage. The approach, which combines the domains of highly dynamic and cyclic experiments as well as different types of numerical simulations, is tested for its performance in the present paper. For this purpose, component tests are carried out on cross-rib beams, which serve to validate the method. The novelty and uniqueness of this paper lies in the linking of fatigue life and crashworthiness considerations for short fibre-reinforced thermoplastics, which, in this case, is raised to a new level by considering the component level for the first time.

Effects of pre-cracked width and seawater erosion on the cracking behavior of SFRC beams with BFRP bars subjected to cyclic loading

This study aims to explore the effects of various pre-cracked widths, seawater erosion and BFRP reinforcement ratios on the cracking behavior of steel fiber reinforced concrete (SFRC) beams with Basalt Fiber Reinforced Polymer (BFRP) bars subjected to cyclic loading. Pre-cracked beams were made by applying loads to obtain a predetermined crack width, such as 0.02 mm, 0.2 mm, and 0.4 mm crack widths. Eleven beams were poured and tested by a four-point bending load under cyclic loading. The crack pattern and load-crack width curves of beams were drawn and analyzed. The effects of pre-cracked width, seawater erosion, and BFRP reinforcement ratio on crack behaviors of beams were investigated and discussed. The results showed that the tensile strength of BFRP bars degenerated after seawater corrosion, and its degradation rates increased with the increase of diameter. The failure mode of beams after seawater erosion may transform from concrete crushing failure to BFRP tensile failure; The maximum crack width of all beams under service load was less than 0.5 mm. Increasing the BFRP reinforcement ratio can significantly improve the crack resistance of beams, but pre-cracked width and seawater erosion had adverse effects on the crack behavior. Existing codes overestimated the crack width of SFRC beams reinforced with BFRP bars. Finally, a new calculation model of crack width of SFRC beams with BFRP bars after seawater corrosion was proposed, and its results were closer to the experimental results.

Behavior of unbonded pre-stressing concrete beams with thermal insulation coating

ABSTRACT Pre-stressing concrete is commonly used in construction. One of the challenges that pre-stressing concrete (PC) faces is that fire exposure reduces the strength and serviceability of PC elements, which requires unique design considerations. The pre-stressing strands are more sensitive to high-temperature, deform larger than mild steel, and break quicker. This research investigates the thermal and structural response of totally unbonded pre-stressing T-beams subjected to increased temperatures and continuous service loads. Thermal coating was proposed to avoid damage and load carrying capacity reduction under fire loading. Seven medium-sized post-tensioned concrete beams were tested in a fire exposure (600°C for 3 h) in order to examine the effect of the following variables: presence of thermal coating, the use of different pre-stressing ratios, increasing the concrete cover, and studying the fire effect at the end anchor, which represents the weakest point at the unbonded system. The proposed insulating technique improved pre-stressing beam behavior during fire exposure by improving crack distribution and lowering strength loss. The thermally insulated beam with a high pre-stressing ratio attained 99.3% of the control specimen load carrying capacity, compared to 86% for the unprotected beam. The deflection of the thermally isolated beam was 7.8 mm, compared to 22.7 mm for the unprotected specimen after 180 min of fire exposure. The use of low pre-stressing ratio caused the insulated pre-stressing strands to rapidly deform with low increases in temperature, which caused rapid crack formation.

Enhancing QoS of Telecom Networks through Server Load Management in Software-Defined Networking (SDN)

In the modern era, with the emergence of the Internet of Things (IoT), big data applications, cloud computing, and the ever-increasing demand for high-speed internet with the aid of upgraded telecom network resources, users now require virtualization of the network for smart handling of modern-day challenges to obtain better services (in terms of security, reliability, scalability, etc.). These requirements can be fulfilled by using software-defined networking (SDN). This research article emphasizes one of the major aspects of the practical implementation of SDN to enhance the QoS of a virtual network through the load management of network servers. In an SDN-based network, several servers are available to fulfill users’ hypertext transfer protocol (HTTP) requests to ensure dynamic routing under the influence of the SDN controller. However, if the number of requests is directed to a specific server, the controller is bound to follow the user-programmed instructions, and the load on that server is increased, which results in (a) an increase in end-to-end user delay, (b) a decrease in the data transfer rate, and (c) a decrease in the available bandwidth of the targeted server. All of the above-mentioned factors will result in the degradation of network QoS. With the implementation of the proposed algorithm, dynamic active sensing server load management (DASLM), on the SDN controller, the load on the server is shared based on QoS control parameters (throughput, response time, round trip time, etc.). The overall delay is reduced, and the bandwidth utilization along with throughput is also increased.