Investigation of waste cooking and castor biodiesel blends effects on diesel engine performance, emissions, and combustion characteristics

Waste cooking (WCO) and castor oils are used as methyl ester feedstocks. By esterification and transesterification of castor and WCO, biodiesels were created and combined with diesel in proportions of 10 % and 20 %. Diesel engine emissions, performance, and combustion were computed at 3000 rpm rated speed and load variation. Highest increases in specific fuel consumption of 2, 3.5, 5.5, 6, and 8.5 % were seen in the cases of waste cooking (10 %), castor biodiesel (10 %), blending (10 %), waste cooking (20 %), and castor (20 %) when diesel fuel was utilized at full load. Thermal efficiencies were decreased by 2.5, 4, 5, 6, and 9.5 % in proportion. Compared to diesel oil, WB10, CB10, WB10+CB10, WB20, and CB20 displayed the biggest reductions in CO emissions of 0.5, 1.5, 2.5, 3, and 3.5 %, respectively; in contrast, NOx concentrations climbed to 1.5, 2.5, 3.5, 5, and 6.5 %, respectively. Largest reductions in hydrocarbon emissions were shown for biodiesel blends as 6, 7, 10, 12, and 14 %, respectively. Largest declines in smoke at peak load were seen for WB10, CB10, WB10+CB10, WB20, and CB20, with respectively values of 6, 8, 10.5, and 11 %. Decrements in maximum cylinder pressure were 1.5, 2, 2.3, 3.5, and 4.5 % at peak load related to diesel. There were 1.5, 2.5, 3, 4.5, and 5 % drops in peak HRR, respectively. Improvement of emissions, performance, and combustion characteristics associated with diesel engine fueled by mixtures of WCO, and castor methyl ester is achieved through the hybridization of feedstocks with different properties as 10 % castor and 10 % WCO biodiesels

Impact Resistance of Styrene–Butadiene Rubber (SBR) Latex-Modified Fiber-Reinforced Concrete: The Role of Aggregate Size

Improvements in tensile strength and impact resistance of concrete are among the most researched issues in the construction industry. The present study aims to improve the properties of concrete against impact loadings. For this purpose, energy-absorbing materials are used along with fibers that help in controlling the crack opening. A polymer-based energy-absorbing admixture, SBR latex, along with polypropylene fibers are used in this study to improve the impact resistance. Along with fibers and polymers, the effect of the size of aggregates was also investigated. In total, 12 mixes were prepared and tested against the drop weight test and the Charpy impact test. Other than this, mechanical characterization was also carried out for all the 12 concrete mixes. Three dosages of SBR latex, i.e., 0%, 4%, and 8% by weight of cement, were used along with three aggregates sizes, 19 mm down, 10 mm down, and 4.75 mm down. The quantity of polypropylene fibers was kept equal to 0.5% in all mixes. In addition to these, three control samples were also prepared for comparison. The mix design was performed to achieve a normal-strength concrete. For this purpose, a concrete mix of 1:1.5:3 was used with a water to a cement ratio of 0.4 to achieve a normal-strength concrete. The experimental study concluded that the addition of SBR latex improves the impact resistance of concrete. Furthermore, an increase in impact resistance was also observed for a larger aggregate size. The use of fibers and SBR latex is encouraged due to their positive results and the fact that they provide an economical solution for catering to impact strains. The study concludes that 4% SBR latex and 0.5% fibers with a larger aggregate size improve the resistance against impact loads

On Robust Optimal Joint Deployment and Assignment of RAN Intelligent Controllers in O-RANs

The open radio access network (O-RAN) architecture is consolidating the concept of software-defined cellular networks beyond 5G networks, mainly through the introduction of the near-real-time radio access network (RAN) intelligent controller (Near-RT RIC) and the xApps. The deployment of the Near-RT RICs and the assignment of RAN nodes to the deployed RICs play a crucial role in optimizing the performance of O-RANs. In this paper, we develop a robust optimization framework for joint RIC deployment and assignment, considering the uncertainty in user locations. Specifically, our contributions are as follows. First, we develop $\text{C}^{3}\text{P}^{2}$ , a robust static joint RIC placement and RAN node-RIC assignment scheme. The objective of $\text{C}^{3}\text{P}^{2}$ is to minimize the number of RICs needed to control all RAN nodes while ensuring that the response time to each RAN node will not exceed $\delta$ milliseconds with a probability greater than $\beta$ . Second, we develop CPPA, a robust joint RIC placement and adaptive RAN node-RIC assignment scheme. In contrast to $\text{C}^{3}\text{P}^{2}$ , CPPA enjoys a recourse capability, where the RAN node-RIC assignment adapts to the variations in the user locations. We use chance-constrained stochastic optimization combined with several linearization techniques to develop a mixed-integer linear (MIL) formulation for $\text{C}^{3}\text{P}^{2}$ . Two-stage stochastic optimization with recourse, combined with several linearization techniques, is used to develop an MIL formulation for CPPA. The optimal performance of $\text{C}^{3}\text{P}^{2}$ and CPPA has been examined under various system parameter values. Furthermore, sample average approximation has been employed to design efficient approximate algorithms for solving $\text{C}^{3}\text{P}^{2}$ and CPPA. Our results demonstrate the robustness of the proposed stochastic resource allocation schemes for O-RANs compared to existing deterministic allocation schemes. They also show the merits of adapting the allocation of resources to the network uncertainties compared to statically allocating them

Management of therapeutic anticoagulation in patients with intracerebral haemorrhage andmechanical heart valves

Aims Evidence is lacking regarding acute anticoagulation management in patients after intracerebral haemorrhage (ICH) with implanted mechanical heart valves (MHVs). Our objective was to investigate anticoagulation reversal and resumption strategies by evaluating incidences of haemorrhagic and thromboembolic complications, thereby defining an optimal time-window when to restart therapeutic anticoagulation (TA) in patients with MHV and ICH. Methods and results We pooled individual patient- data (n = 2504) from a nationwide multicentre cohort-study (RETRACE, conducted at 22 German centres) and eventually identified MHV-patients (n = 137) with anticoagulation-associated ICH for outcome analyses. The primary outcome consisted of major haemorrhagic complications analysed during hospital stay according to treatment exposure (restarted TA vs. no-TA). Secondary outcomes comprised thromboembolic complications, the composite outcome (haemorrhagic and thromboembolic complications), timing of TA, and mortality. Adjusted analyses involved propensity-score matching and multivariable cox-regressions to identify optimal timing of TA. In 66/137 (48%) of patients TA was restarted, being associated with increased haemorrhagic (TA = 17/66 (26%) vs. no-TA = 4/71 (6%); P < 0.01) and a trend to decreased thromboembolic complications (TA = 1/66 (2%) vs. no-TA = 7/71 (10%); P = 0.06). Controlling treatment crossovers provided an incidence rate-ratio [hazard ratio (HR) 10.31, 95% confidence interval (CI) 3.67-35.70; P < 0.01] in disadvantage of TA for haemorrhagic complications. Analyses of TA-timing displayed significant harm until Day 13 after ICH (HR 7.06, 95% CI 2.33-21.37; P < 0.01). The hazard for the composite-balancing both complications, was increased for restarted TA until Day 6 (HR 2.51, 95% CI 1.10-5.70; P = 0.03). Conclusion Restarting TA within less than 2 weeks after ICH in patients with MHV was associated with increased haemorrhagic complications. Optimal weighing-between least risks for thromboembolic and haemorrhagic complications-provided an earliest starting point of TA at Day 6, reserved only for patients at high thromboembolic risk