Load Drop Research Articles

Recycling Unrecycled Plastic and Composite Wastes as Concrete Reinforcement

The land disposal of waste material is a major environmental threat, and recycling efforts must be exponentially improved to mitigate it. In this paper, a feasibility study was conducted to reinforce concrete with waste materials that are not typically recycled. Compression testing was performed to evaluate the mechanical properties of the concrete specimens. The results were compared with a conventional wire mesh reinforcement used in concrete. Alternative reinforcements that are typically disposed of in landfill were used, namely, plastic regrind, carbon fiber scraps, tempered glass, coarse aggregates, and wire mesh. For each reinforcement type, four specimens were manufactured to evaluate the consistency of the results. Cylindrical specimens with ASME standard dimensions of 10.16 cm × 20.32 cm were tested using a Tinius-Olsen compression testing machine after seven days of curing. A constant strain rate of 0.25 MPa/s was applied until a load drop of 30% was detected. The results show that, while the recycled reinforcements had lower compressive strengths than the wire mesh, they maintained a load-carrying capacity of more than 80%. A major improvement was observed in terms of the ductility and toughness of the reinforced concretes. The recycled-carbon-fiber-reinforced specimens showed 12% strain at failure, a major improvement in concrete ductility. The findings of this research indicate that such recycled particles and fibers without any post-processing can be used in the reinforcement of concrete, with a significant improvement in ductility.

Analysis of the behaviour of the floating pipe pile foundation on soft soil

Planning the foundation according to the characteristics of the soil is the most important thing before starting construction. In recent studies, the use of PVC pipe pile foundations has been introduced. These foundations, called floating foundations, offer a lighter and more economical solution for simple buildings on soft soils. The study involved variations in pipe diameters of consistent lengths. In laboratoryscale axial loading tests, the behaviour of pipe stacks against load drop is observed. The bearing capacity of pipe piles is evaluated through a static loading test, with one end of the pipe pile hermetically sealed and aspirated in an alternating pile in a glass box filled with soft soil with a content of 98%. The results of this test are then analyzed with the Chin Method Interpretation to determine the carrying capacity and behaviour of pipe piles against soft soil, The results of the analysis show that the diameter of the pipe piles has a significant effect on the bearing capacity of the foundation. Although the results are promising, further research is still needed, especially in the development of foundation construction suitable for multi-storey buildings in areas with soft soil or peat

A Reputation Management System for the Fair Utilization of Community Energy Storage Systems

This paper investigates the implementation of a community energy storage system (CESS) in a neighborhood consisting of households with flexible and inflexible loads, as well as photovoltaic power generation. The system incorporates overlay services (OS) such as fairness management, increasing the fairness level while maximizing CESS utilization, and reputation management, reducing the impact of households trying to take advantage of the system. Additionally, a credit scheme for households, referred to as the quota system, is introduced, allowing households to only import from the battery the amount of energy they have previously contributed. This quota system includes a way to trade credit with other households, as part of the OS. The case study shows that the introduction of the OS on top of a CESS of 50 kWh results in a drop in peak transformer load from 235.7% to 166.9%, with the peak load at 264.3% without a CESS present. Additionally, it is shown that introducing these OS in a CESS does not significantly impact the mean household cost.

Direct tension tests for determining the relationship between tensile stress and crack opening of ultra-high performance concrete

This study reports the test results of direct tension tests of ultra-high performance concrete (UHPC) and ultra-high performance fiber reinforced concrete (UHPFRC). The idealized model of tensile stress versus crack opening was described for the prediction of tensile behavior. The mixtures of UHPC and UHPFRC were designed to achieve a compressive strength of 200 MPa. The direct tension tests were conducted on the prisms of 40x40x80 mm with notches of 5x5 mm in the middle of the prisms. The test results indicated that UHPC prisms failed in a brittle manner with a sudden drop of load in the descending branch, while UHPFRC prisms failed in a ductile manner with a strain hardening stage after the cracking stress and with a softening stage after the ultimate stress. The crack opening of UHPFRC prisms was much higher than that of UHPC prisms. The values of cracking stress, ultimate stress, and crack opening were significantly improved by increasing the volume of steel fibers from 1% to 2%. The prisms with small dimensions were adopted for the direct tension tests in this study, thus leading to the feasibility of testing and reducing the cost.

Effect of Convalescent Plasma Therapy on Mortality and Viral Load in Severely Ill Patients with COVID-19.

The use of convalescent plasma (CP) appeared to be a promising, easily available and safe way of treatment of severe COVID-19 at the onset of the pandemic in early 2020. Conducted in 2020 and 2021, our study of 52 severely to critically ill COVID-19 patients who received CP plasma as a treatment and of 97 controls found no difference in 30-day or 90-day mortality rates. A significant viral load drop in most patients (4.7 log10 [p<0.001] copies/ml) was observed following CP administration. Retrospective analysis of selected inflammatory markers and immunoglobulins showed higher C-reactive protein levels among the study group, and their decrease on Day 7.

Behavior of two-way RC slab with different reinforcement orientation layouts of tension steel under drop load impact

In this research work, dynamic nonlinear incremental finite element analysis is conducted in ABAQUS software with an inbuilt explicit module to study the impact response of a two-way singly reinforced concrete slab, 1000 mm × 1000 mm × 75 mm, with different flexural tension steel reinforcement orientation layouts subjected to low-velocity falling-weight impact loading by cylindroconical impactor with a flat nose of 40 mm diameter having overall mass 105 kg from 2500 mm drop height. Computational findings are found in consonance with experimental results of Sadraie et al. (2019) on an isotopically reinforced concrete slab of the same dimensions with flexural tension steel in two layers i.e., one at 90-degree and the other at 180-degree orientations, subjected to the same impact load. Local damage in the form of punching occurs in the immediate vicinity of the impacted region. Overall deformation and cracking reflect the global behavior of the slab. The slab reinforcement is improvised by providing the same tension steel (0.88 %) in three layers: the first- and third- layer having orientation layouts of (a) 30- & 150-degree, (b) 45- & 135-degree, (c) 60- & 120-degree, and (d) 75- & 105-degree; the second layer is common with 90-degree orientation, and analyses are carried out under the same impact load. The Concrete Damage Plasticity and Johnson-Cook models, respectively, including the strain rate effects, are chosen to define concrete and steel materials’ response under impulsive impact loading. Computational results are discussed and presented in terms of displacement–time plots, stress distribution in the concrete and reinforcing bars, damage dissipation energy, and damage profiles. The tension steel in three layers and its orientation is found to have a noteworthy influence on the response of the slab and reduces the damage severity under impact loading.

Effect of using Engineered Cementitious Composites (ECC) on failure behavior of flat slab-column connections

Load capacity and ductility are two key characteristics of the flat slab-column connection in high seismic areas. This study specifically examined the effect of strengthening layer thickness of Engineered Cementitious Composites (ECC) on punching shear strength and post punching behavior of flat slabs. The effect of the unbalanced moment, ECC thickness of the slab and the strengthening ECC layer on flat slab punching and post punching behavior were also investigated. Thirteen reinforced concrete flat slab specimens were made and examined. It was observed that the replacement of slab concrete with ECC increased the punching capacity and improved post-punching behavior without a large and sudden drop in load. In addition, the use of ECC as a strengthening layer for the flat slabs significantly increased the punching and post-punching shear strength capacities. The change in failure mechanism was observed from a sudden and abrupt failure to a ductile failure with high-energy absorption when more ECC layer thicknesses were used.

Load versus displacement-controlled nanocompression: Insights from atomistic simulations

The mechanics of nano-objects strongly depend on the experimental setup used. Indeed, experimental devices generate stress either by controlling the force exerted by the grips (or indenters) or by monitoring their displacements, while software-based feedback loops are also developed to control displacements using force actuators. Often, nanomechanical experiments are interpreted using intrinsically displacement-controlled molecular dynamics simulations, without questioning the influence of the control mode. In this study, we develop an original strategy to perform load-controlled molecular dynamics simulations applied here to nanoparticles under compression as a test-case. While displacement-controlled simulations show intermittent plasticity and load drops, load-controlled simulations are characterized by strain-bursts more in line with load-controlled experiments. Here, a special attention is paid to the dislocation microstructure evolution depending on the control mode. Finally, interpretations of recent experiments based on atomistic simulations are revised, including the envelope load model usually used to correlate displacement-controlled atomistic simulations and load-controlled experiments at small-scales.

Investigation of rotating detonation gas turbine cycle under design and off-design conditions

As cycle efficiency of gas turbine can be significantly improved due to the pressure gain characteristic of rotating detonation combustion, a cycle calculation model of rotating detonation gas turbine based on component characteristic curves of a single shaft gas turbine of 25 MW and limited maximum flow capacity of rotating detonation combustor was established to investigate the variations of cycle performance and component characteristics under design and off-design conditions. Thereafter, sensitivity analysis of component parameters was conducted to explore the comprehensive reason for change of cycle efficiency increment. The results demonstrated that compared with those of traditional gas turbine, higher cycle performance and lower compressor pressure ratio were gained in rotating detonation gas turbine. Increment of cycle efficiency and cycle net power increment significantly increased with the drop of load, which reached to 0.0248 and 3.261 MW when turbine inlet total temperature was 1450 K and increased to 0.0539 and 4.008 MW when turbine inlet total temperature was 1279 K. Cycle performance was significantly affected by the changes of compressor pressure ratio, compressor efficiency, equivalence ratio of RDC and turbine efficiency, among which turbine efficiency rather than compressor outlet total temperature had the most significant effect on cycle efficiency increment under the calculated conditions.

Compression properties of carbon fiber reinforced polymer grid sandwich structure

Carbon fiber reinforced polymer (CFRP) grid sandwich structure with four different grid configurations was prepared using the interlocking assembly process in the present work. All test specimens were subjected to quasi-static out-of-plane uniform compression. The equivalent density, height, geometric configuration, and other factors of the structural core layer were analyzed, and their effects on the failure mode, damage mechanism, and energy absorption characteristics of CFRP grid sandwich structure were discussed. The results showed that there are four distinct stages in the load versus displacement curve of CFRP grid sandwich structure specimens subjected to uniform compression, namely, preloading stage, elastic stage, load drop stage, and platform stage. The main failure modes of CFRP grid sandwich structure are the local buckling and compression fracture of the core rib. The failure load, compression strength, breaking absorbed energy, and specific absorbed energy of CFRP grid sandwich structure are positively correlated with the equivalent density of the structure core layer, and negatively correlated with the height of the structure core layer. When the equivalent density of the core layer of the Mixed CFRP grid sandwich structure was increased by 10 kg/m3, the compressive strength and specific energy absorption of the structure increased by about 5.08 MPa and 186.79 mJ, respectively, and when the core layer height was increased by 10 mm, the compressive strength and specific energy absorption decreased by about 12.04 MPa and 67.39 mJ, respectively; The strength and stability of the Mixed CFRP grid sandwich structure are significantly higher than those of the Triangular, Diamond, and Square CFRP grid sandwich structures.

Evaluation and Prediction of Pavement Deflection Parameters Based on Machine Learning Methods

The deflection measurements made using Falling Weight Deflectometers (FWDs) are widely used in the back-calculation of pavement layer moduli. Pavement structural characteristics, changes in temperature, and other related factors exert a significant effect on the deflection measurements. Therefore, three machine learning methods—Classification and Regression Tree (CART), Random Forest (RF), and Gradient Boosting Decision Tree (GBDT)—were used to evaluate the importance of influencing factors including FWD test conditions, pavement structural parameters, climatic factors, traffic level, rehabilitation level, and service age, on the FWD measurements of deflection basin in this study. The results indicated that structural number was an important feature for all FWD measurements but its importance on lg(D0–D20) and lg(D0–D30) was smaller than other FWD measurements. The relative feature importance of the asphalt layer, base, and subbase on lg(D0–D20) and lg(D0–D30) was asphalt layer > subbase > base; their relative importance on lg(D20–D60), lg(D30–D60), and lg(D30–D90) was asphalt layer > base > subbase; and their relative importance on lg(D90−D120) and lg(D60–D120) was base > subbase > asphalt layer. Among the FWD test condition variables, drop load was the most significant factor influencing deflection measurements. The second-layer temperature was also important for lg(D0–D20), lg(D0–D30), and lg(D0–D45). The importance of precipitation was greater than the freeze index. The prediction results shown that the accuracy of GBDT was as high as 99%. Besides, GBDT outperformed RF, and RF outperformed CART. The analyses between FWD deflection parameters and influencing factors, especially the structural characteristics of the pavement, provide theoretical evidence for the evaluation of pavement layer strength on the basis of FWD data.

A Case of Acute Disseminated Histoplasmosis of the Liver in a Patient Receiving Amphotericin-B Therapy

Abstract Introduction/Objective Acute disseminated histoplasmosis (DH), caused by Histoplasma Capsulatum (HC), occurs primarily in immunocompromised hosts. It is characterized by an abrupt onset of symptoms (fever, malaise, hepatosplenomegaly, lymphadenopathy, anemia, leucopenia and thrombocytopenia) and a lack of granulomatous inflammatory response. If left untreated, death occurs within three months of the disease. The treatment of choice is a two-week course of Amphotericin-B (AmpB-Tx). Studies show a drop in fungal load in 85% of blood cultures and a drop of 1.6 U and 2.1 U in serum and urine antigen levels of histoplasmosis respectively, within 14 days of treatment thereby making it unlikely to see liver failure secondary to acute DH in a patient receiving AmpB-Tx. Methods/Case Report We present a case of a 41-year-old male, newly diagnosed with HIV (CD4=44; viral load=5,350,000) and DH on AmpB-Tx. At presentation, his liver function tests (LFT’s) were mildly elevated (Bilirubin =2.7mg/dL; ALP=259U/L; AST=271U/L; ALT=71U/L). On Day-9 of AmpB-Tx, he became somnolent and jaundiced with hepatosplenomegaly and ascites. His LFTs were markedly raised, showing an obstructive pattern (Bilirubin=16mg/dL; ALP=1578U/L; AST=261U/L; ALT=213U/L). On Day-11 of treatment, we received a liver biopsy for HIV cholangiopathy versus drug induced hepatotoxicity. The clinicians considered DH to be a less likely cause since the patient was already on AmpB-Tx. The liver biopsy showed hepatocytes with cholestasis, minimal acute portal inflammation and numerous portal tract and parenchymal macrophages laden with fungal organisms. Gomori-Methenamine-Silver stain confirmed the fungal organisms as being HC. This diagnosis prompted the continuation of AmpB-Tx past 14 days. The patient’s LFT’s reached maximum values of Bilirubin=18mg/dL; ALP=1680U/L; AST=355U/L; ALT=324U/L. After 25 days of AmpB-Tx, his LFT’s trended downwards with a resolution of his hepatic encephalopathy and jaundice. While a 14 day course was initially intended, AmpB-Tx was continued for a total of 28 days until a resolution of symptoms was achieved. Results (if a Case Study enter NA) NA. Conclusion Our case identifies a patient with progressive hepatic histoplasmosis in spite of AmpB-Tx. Keeping in mind and identifying such cases on pathology can alter the course of treatment for patients.

Design and analysis of a MEMS inertial switch with the time delay characteristic

A novel MEMS inertial switch with the time delay characteristic was proposed, which can distinguish between two typical impact loads in SAD (15000 g - 0.3 ms and 6000 g - 1 ms) by friction between the movable parts. The switch is composed of an outer mass-spring served as a movable electrode, a pair of flexible electrodes, an inner mass-spring, and a pair of friction bars. Its dynamic response under the action of impact load is divided into three phases, and theoretical models for each phase were established by Duhamel integration. Finite element analysis was performed to verify the time delay characteristic and that it is capable of distinguishing between a typical accidental drop load and a normal launching load. Under the action of impact loads of 6000 g - 1 ms and 6000 g - 1.2 ms, the switch has a delay time of 340 μs and 402 μs, respectively, and a holding time of over 365 μs and 480 μs, respectively.

Imitating Spiders to catch flying insects: Realizing high-strength bonding of bamboo scraps/magnesium oxychloride lightweight composite interface

Compatible interface is the key to designing low-carbon building materials containing plant fiber. Moisture migration causes steric hindrance at interfaces, resulting in materials with poor two-phase interface compatibility and low mechanical strength. Drop load presents a serious threat to the structural safety of future houses. Firmer cementation in composite becomes an urgent problem. We report on a strategy using polysaccharide chains between two different phases, and design high-strength adhesion interface. This new design is inspired by the behavior of spiders to catch flying insects. The presence of hydroxyl and amino groups on the spider silk surface allows binding of flying insects with high strength and using only small contact area. To mimic that strategy, MgO was used for orderly crystallization on the polymer chain and active hydroxyl groups with high specific surface area achieves multidimensional and multi-site adhesion of bamboo scraps. Improved interfacial compatibility facilitates the formation of heterogeneous but continuous phase structure. The compressive stress reaches 4.66 MPa and softening factor is 0.74 for density of 0.37. The designed material is an advanced composite in construction and decoration. Its low-loading characteristic can reduce carbon footprint calculations, suggesting this strategy has significant potential for future development.

Study on the most severe condition for structural assessment of nuclear fuel transport package under impact loading

Advanced nuclear fuel transport packages are being needed to meet the fuel requirement for an increasing number of nuclear power plants. They must be approved by the IAEA safety standard where 9-m free drop test is a major concern in the overall assessments. As in the regulations, it is necessary to find the most severe condition, i.e., maximum damage of the nuclear fuel transport package. In this study, an integrated method with grey relational analysis (GRA) method and the quaternary triangular mesh (QTM) spherical sampling model is proposed to determine the maximum damage of package under drop loading. The finite element (FE) model of the HTR-PM600 fresh fuel transport package is firstly established for the drop analysis. On this basis, the design of experiment (DOE) for the design variables and design space (i.e. drop orientation) is carried out using the QTM. Then four selected orientations are determined through GRA and the main effect analysis. It is followed by the detailed analysis with respect to the safety performance. The results show that these orientations demonstrate important and irreplaceable potential as the most severe condition. This work can provide a reference to improve design of nuclear package.

SIRPα maintains macrophage homeostasis by interacting with PTK2B kinase in Mycobacterium tuberculosis infection and through autophagy and necroptosis.

SummaryBackgroundTo determine whether SIRPα can be a diagnostic marker of pulmonary tuberculosis (PTB) and the molecular mechanism of SIRPα regulating macrophages to kill Mycobacterium tuberculosis (MTB).MethodsMeta-analysis combined with subsequent qRT-PCR, western-blotting and flow cytometry assay were used to detect SIRPα expression in PTB patients. Cell-based assays were used to explore the regulation of macrophage function by SIRPα. SIRPα−/- and wide type macrophages transplanted C57BL/6J mice were used to determine the function of SIRPα on MTB infection in vivo.FindingsSIRPα levels are closely correlated with the treatment outcomes among PTB patients. Cell-based assay demonstrated that MTB significantly induces the expression of SIRPα on macrophages. SIRPα deficiency enhances the killing ability of macrophages against MTB through processes that involve enhanced autophagy and reduced necroptosis of macrophages. Mechanistically, SIRPα forms a direct interaction with PTK2B through its intracellular C-terminal domain, thus inhibiting PTK2B activation in macrophages. Necroptosis inhibition due to SIRPα deficiency requires PTK2B activity. The transfer of SIRPα-deficient bone marrow-derived macrophages (BMDMs) into wild type mice resulted in a drop of bacterial load in the lungs but an enhancement of inflammatory lung damage, and the combination of ulinastatin and SIRPα−/−→WT treatment could decrease the inflammation and maintain the bactericidal capacity.InterpretationOur data define SIRPα a novel biomarker for tuberculosis infection and underlying mechanisms for maintaining macrophage homeostasis.FundingThis work was financially supported by the Chinese National Natural Science Foundation project (No.81401635). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Impact of aerosols and reactive trace gases concentrations in India

The current scenario united the elite professionals, researchers and scientists throughout the globe to accelerate the sharing of scientific findings making the future brighter on mother Earth. The concentration of reactive trace gases in the atmosphere modulates the human health appreciably. This study presents the changes of aerosol and reactive gases load in the atmosphere from the recent past with the help of CAMS data in Indian domain. Reactive trace gases and aerosols (NO2, O3, SO2, CO & AOD) are now being recognised as having both positive and negative radiative forcing effects. The effects of changes have been studied and found that the concentration of chemically reactive gases and aerosols load drop down from their 17 years long period average (LPA) appreciably (60-70 %) over IGP and 35-40 % in other parts of India except O3 (Increase 20-30 %) in India during the month of April-2020.
 It is observed that the results are agrees quite well with the actual recorded data of CPCB stations located at 12 different places of India. The difference observed between actual observations and CAMS reanalysis during April -2019 & 2020 show that aerosol load in terms of PM-2.5 & PM-10 is appreciably drop down (60-70 %) over IGP and 25-30 % in other parts of India. The concentration of other reactive gases (NO2, SO2 &CO) also drops down about 32 %, 7 %, 17 % over IGP and 16 %, 8 %, 9 % in other parts of India respectively. The concentration of Ozone shows slightly positive behaviour over IGP and negative at other parts of India. 
 Few pockets of Central and South of India show higher concentration may due to ongoing essential activities of cluster of industries or delayed slowdown. The other reason may be the influx of moisture due to the pre-monsoon thunder storm activity during this period. Vertical air flow Omega (positive) at 850 hPa NCEP/NCAR reanalysis also support the confinement of gases at lower levels. This study is further brought out a message for future that we should use the natural resources judiciously as their long term consumption can cause severe health problems and a psychological burden or stress globally during this COVID-19 spread period.

Stiffness-based method to identify the threshold load of low hardness steels using the Incremental step loading test

Hydrogen embrittlement (HE) is one of the main problems related to the use of metallic materials in sour or wet environments. The Incremental Step-Loading (ISL) test used to evaluate the susceptibility to HE of steels has gained more visibility over recent years, thus allowing for the determination of the threshold load (Pth) in H+ enriched environments. However, the ISL standard, ASTM F1624, limits the test to steels with a minimum hardness of 33 HRC. Even for those steels with 33 HRC, the results present some misinterpretations. In addition to this fact, one needs to consider that there are several applications where steels with hardness below 33 HRC are used, as for instance, in fasteners and tool joints under cathodic protection used in the oil and gas industry, for which hardness varies from 26 to 32 HRC. In light of the aforementioned, the standard limitation represents a major disadvantage related to the application of the ISL test. Grounded upon the said, the aim of the present study is to propose a methodology based on the specimen stiffness to be used in the ISL test results, allowing the Pth determination of steels with hardness lower than 33HRC. Conventional and extended ISL tests were performed in two steels (4137-M and 4130-M) with a 32HRC hardness values. Applying the stiffness-based method on the the conventional ISL test results, a threshold load (Pth) of 71.5 %PFFS and 66.0 %PFFS were found for the 4137-M and 4130-M steels, respectively. To validate these results, extended ISL tests were performed on both steels and the results showed a Pth of 73.7 %PFFS for the 4137-M steel and 66.0 %PFFS for the 4130-M steel. The results from the conventional ISL test, using the stiffness-based method proposed in this study, provided values similar or with differences lower than 5 %PFFS, when compared alongside the extended ISL tests. Moreover, ISL tests were performed on the same steels with 40 HRC hardness, and the AISI4137-M presented a Pth of 21.6 %PFFS and for 4130-M the Pth was 22.0 %PFFS. The main conclusion obtained from these tests was that, when large amount of plastic deformation is not present on ISL test, the load drop visual detection is sufficient to determine the Pth. As expected, it was observed that both steels with 40 HRC presented higher HE susceptibility than the 32 HRC ones. This behavior was due to higher stress concentration at the notch root presented by the higher hardness condition. The stiffness-based method proved to be robust and capable of separate yielding from hydrogen induced cracking of low hardness steels and could also be used to identify the Pth values of steels with hardness lower than that specified by the ASTM F1624 standard, and which are tested using the ISL test.

Experimental study on the dynamic performance of an air-cooled proton exchange membrane fuel cell stack with ultra-thin metal bipolar plate

In this paper, a compact 3 kW air-cooled fuel cell stack consists of 95 single cells with metallic bipolar plate is designed. Compared with graphite bipolar plates, metal stamping bipolar plates are lighter in weight, smaller in size and faster in heat conduction, therefore the transient behaviors of the voltage and temperature of each cell are analyzed. The results show that the heat distribution of the air-cooled fuel cell is very uniform, and the temperature difference between the inlet and outlet of cathode air of the fuel cell is lower than 15 °C. The individual cell voltage uniformity percentage variation value reaches 7% when the drop in the loading current is over 25 A. Moreover, the voltage uniformity variation value is higher than 4% when the loading current output exceeds 35A. Thus, a large drop in loading and a high loading current easily increase the voltage uniformity variation value. Long-term continuous operation has a negative influence on the performance of the stack, especially the last fuel cell near the anode outlet. Anode purging can effectively alleviate the uniformity percentage variation in the voltages. The designed air-cooled fuel cell exhibits good performance and strong environmental adaptability.

Routing Protocol for MANET Based on QoS-Aware Service Composition with Dynamic Secured Broker Selection

MANET is a mobile ad hoc network with many mobile nodes communicating without a centralized module. Infrastructure-less networks make it desirable for many researchers to publish and bind multimedia services. Each node in this infrastructure-less network acts as self-organizing and re-configurable. It allows services to deploy and attain from another node over the ad hoc network. The service composition aims to provide a user’s requirement by combining different atomic services based on non-functional QoS parameters such as reliability, availability, scalability, etc. To provide service composition in MANET is challenging because of the node mobility, link failure, and topology changes, so a traditional protocol will be sufficient to obtain real-time services from mobile nodes. In this paper, the ad hoc on-demand distance vector protocol (AODV) is used and analyzed based on MANET’s QoS (Quality of Service) metrics. The QoS metrics for MANET depends on delay, bandwidth, memory capacity, network load, and packet drop. The requester node and provider node broker acts as a composer for this MANET network. The authors propose a QoS-based Dynamic Secured Broker Selection architecture (QoSDSBS) for service composition in MANET, which uses a dynamic broker and provides a secure path selection based on QoS metrics. The proposed algorithm is simulated using Network Simulator (NS2) with 53 intermediate nodes and 35 mobile nodes of area 1000 m × 1000 m. The comparative results show that the proposed architecture outperforms, with standards, the AODV protocol and affords higher scalability and a reduced network load.