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result(s) for
"Optimized performance"
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Exploring the Benefits of Karanja-Oil-Derived Biodiesel-Water Emulsion as a Potential Fuel for Diesel Engines Operated with High-Pressure Fuel Injection Systems
by
Krishnasamy, Anand
,
Gowrishankar, Sudarshan
,
Aidhen, Indrapal Singh
in
Biodiesel fuels
,
Biodiesel-water emulsion
,
Carbon monoxide
2024
Biodiesel is a suitable alternative to diesel because of its carbon neutrality, renewability, lubricity, and lower pollutant emissions. However, extensive research indicates higher oxides of nitrogen (NOₓ) emissions with biodiesel. A practical method to combat this problem is utilizing water and biodiesel as emulsions. The effect of biodiesel-water emulsion in high-pressure fuel injection systems is not fully explored in the existing literature. The present study addresses this research gap by utilizing biodiesel-water emulsions in a modified light-duty diesel engine. The governor-controlled injection system was adapted to a fully flexible electronic system capable of high-pressure injection. Unlike other literature studies, the fuel injection timings were optimized with biodiesel-water emulsions to maximize brake thermal efficiency (bte) at every load condition. In a novel attempt, the biodiesel source, i.e., raw Karanja oil (RKO), a triglyceride, was utilized as the surfactant to stabilize the biodiesel-water emulsions containing 6%, 12%, and 18% water. The emulsions reduced the ignition delay and cylinder pressures, with less-intense premixed combustion and a more significant diffusion phase combustion than biodiesel. The emulsions also present a delayed combustion phasing following the injection timing trends. Among the tested emulsions, at 5.08 bar brake mean effective pressure (BMEP), 18% biodiesel-water emulsion resulted in an 18% reduced brake specific fuel consumption (bsfc), 5% increase in bte, 30% and 7% mitigation in NOₓ and smoke levels, with an increase of 10% and 28% for unburned hydrocarbon (HC) and carbon monoxide (CO) emissions.
Journal Article
Mitigating Membrane Fouling in Abattoir Wastewater Treatment: Integration of Pretreatment Step with Zwitterion Modified Graphene Oxide–Polyethersulfone Composite Membranes
by
Motloutsi, Meladi L.
,
Managa, Muthumuni
,
Matebese, Funeka
in
abattoir wastewater
,
Abattoirs
,
Activated carbon
2024
Composite polyethersulfone (PES) membranes containing N-aminoethyl piperazine propane sulfonate (AEPPS)-modified graphene oxide (GO) were integrated with either of the two pretreatment processes (activated carbon (AC) adsorption or polyelectrolyte coagulation) to assess their effectiveness in mitigating membrane fouling during the treatment of abattoir wastewater. The AEPPS@GO-modified membranes, as compared to the pristine PES membranes, showed improved hydrophilicity, with water uptake increasing from 72 to 118%, surface porosity increasing from 2.34 to 27%, and pure water flux (PWF) increasing from 235 to 673 L.m−2h−1. The modified membranes presented improved antifouling properties, with the flux recovery ratio (FRR) increasing from 59.5 to 93.3%. This study compared the effectiveness of the two pretreatment processes, AC, coagulation, and the integrated system (coagulation/AC-UF membrane), in the removal of natural organic matter (NOM) and improvement of abattoir wastewater’s pH, electrical conductivity, TDS, and turbidity. The integrated systems produced improved water quality in terms of pH, EC, TDS, turbidity, and organic content. The fluorescence excitation–emission matrix (FEEM) analysis exhibited almost no fluorescence peak post-treatment following organic loading removal. The quality of the water met the South African non-potable water reuse standards. The sole membrane treatment systems exhibited good fouling resistance without the pretreatment systems; however, integrating these systems can offer extended longer filtration periods, thereby assisting in cost aspects of the abattoir wastewater treatment system.
Journal Article
Research on the Structure Design and Mechanical Properties of Performance Optimized Multi-Axial Geogrid
2022
In order to solve the problem of low transverse tensile strength of triaxial geogrid, a kind of performance-optimized multi-axial geogrid (POMG) that can bear larger transverse loads was designed. Firstly, the forming equipment and process of POMG are designed. Secondly, through the test of formability and mechanical properties, the POMG with good formability and mechanical properties is obtained, and the average tensile strength of POMG with circular and semicircular holes is the highest, reaching more than 16 KN/m. Finally, the feasibility of the process is further verified by numerical simulation, and the shape distribution and stress-strain law of POMG during the forming process are obtained, which provides further guidance for the actual production.
Journal Article
Optimized strain performance in -textured Bi0.5Na0.5TiO3-based ceramics with ergodic relaxor state and core—shell microstructure
by
Zhou, Xuefan
,
Yang, Huiping
,
Xue, Guoliang
in
Antiferroelectricity
,
Bismuth titanate
,
Ceramics
2022
Herein, a high strain of ∼0.3% with a small hysteresis of 43% is achieved at a low electric field of 4 kV/mm in the highly -textured 0.97(0.76Bi
0.5
Na
0.5
TiO
3
−0.24SrTiO
3
)−0.03NaNbO
3
(BNT−ST−0.03NN) ceramics with an ergodic relaxor (ER) state, leading to a large normalized strain (
d
33
*) of 720 pm/V. The introduction of NN templates into BNT−ST induces the grain orientation growth and enhances the ergodicity. The highly -textured BNT−ST−0.03NN ceramics display a pure ergodic relaxor state with coexisted ferroelectric
R
3
¯
c
and antiferroelectric
P4bm
polar nanoregions (PNRs) on nanoscale. Moreover, due to the incomplete interdiffusion between the NN template and BNT−ST matrix, the textured ceramics present a core-shell structure with the antiferroelectric NN core, and thus the BNT-based matrix owns more
R
3
¯
c
PNRs relative to the homogeneous nontextured samples. The high crystallographic texture and more
R
3
¯
c
PNRs both facilitate the relaxor-to-ferroelectric transition, leading to the low-field-driven high strain, while the ergodic relaxor state ensures a small hysteresis. Furthermore, the
d
33
*
value remains high up to 518 pm/V at 100 °C with an ultra-low hysteresis of 6%.
Journal Article
Activated carbon as a catalyst to promote the reactivity of hydroquinone in skin whitening cosmetics
2025
This review paper explores the application of activated carbons (ACs) in skin whitening cosmetics and their basic characteristics as a catalyst. Firstly, the physical and chemical properties of ACs, as well as their theoretical basis as catalysts, were introduced. Subsequently, a detailed analysis was conducted on the mechanism of ACs in promoting the reactivity of hydroquinone (HQ), including physical adsorption, chemical interactions, and the role of surface functional groups. The paper compared the performance of different types of ACs such as wood-based, coconut shell-based, coal-based, and supported ACs in catalytic reactions and compared them with other catalysts. In order to optimize the catalytic performance of ACs, strategies for changing preparation methods and conditions were explored, such as physical and chemical activation methods, microwave-assisted preparation, and adjustment of carbonization temperature and time. In addition, the paper also discusses the potential advantages of ACs in whitening cosmetics, such as improving the effectiveness of whitening ingredients and enhancing product safety, as well as the challenges faced, including stability issues and possible side effects. The future development directions include innovation and improvement of AC-materials, in-depth research on their interaction with the skin, development of composite materials, and the application of green chemistry in the preparation of ACs. Finally, the paper explores the binding mechanism of ACs with other whitening agents and its limitations in formulation and environment and summarizes the application prospects of ACs in cosmetics.
Journal Article
An interior-point implementation developed and tuned for radiation therapy treatment planning
by
Breedveld, Sebastiaan
,
van den Berg, Bas
,
Heijmen, Ben
in
Convex and Discrete Geometry
,
Derivatives
,
Management Science
2017
While interior-point methods share the same fundamentals, the implementation determines the actual performance. In order to attain the highest efficiency, different applications may require differently tuned implementations. In this paper we describe an implementation specifically designed for
optimisation in radiation therapy
. These problems are large-scale nonlinear (and sometimes nonconvex) constrained optimisation problems, consisting of both sparse and dense data. Several application-specific properties are exploited to enhance efficiency. Permuting, tiling and mixed precision arithmetic allow the algorithm to optimally process the mixed dense and sparse data matrices (making this step 2.2 times faster, and overall runtime reduction of
55
%
) and scalability (16 threads resulted in a speed-up factor of 9.8 compared to singlethreaded performance, against a speed-up factor of 7.7 for the less optimised implementation). Predefined cost-functions are hard-coded and the computationally expensive second derivatives are written in canonical form, and combined if multiple cost-functions are defined for the same clinical structure. The derivatives are then computed using a scaled matrix–matrix product. A cheap initialisation strategy based on the background knowledge reduces the number of iterations by
11
%
. We also propose a novel combined Mehrotra–Gondzio approach. The algorithm is extensively tested on a dataset consisting of 120 patients, distributed over 6 tumour sites/approaches. This test dataset is made publicly available.
Journal Article
Environmental approaches to controlling Clostridioides difficile infection in healthcare settings
by
Parry, Michael F.
,
Carling, Philip C.
,
Olmstead, Russell
in
Antibiotics
,
Biomedical and Life Sciences
,
Biomedicine
2023
As today’s most prevalent and costly healthcare-associated infection, hospital-onset
Clostridioides difficile
infection (HO-CDI) represents a major threat to patient safety world-wide. This review will discuss how new insights into the epidemiology of CDI have quantified the prevalence of
C. difficile
(CD) spore contamination of the patient-zone as well as the role of asymptomatically colonized patients who unavoidable contaminate their near and distant environments with resilient spores. Clarification of the epidemiology of CD in parallel with the development of a new generation of sporicidal agents which can be used on a daily basis without damaging surfaces, equipment, or the environment, led to the research discussed in this review. These advances underscore the potential for significantly mitigating HO-CDI when combined with ongoing programs for optimizing the thoroughness of cleaning as well as disinfection. The consequence of this paradigm-shift in environmental hygiene practice, particularly when combined with advances in hand hygiene practice, has the potential for significantly improving patient safety in hospitals globally by mitigating the acquisition of CD spores and, quite plausibly, other environmentally transmitted healthcare-associated pathogens.
Journal Article
Optimized Performance and Economic Assessment for Hybrid Island Microgrid System Considering Uncertainties
by
Hoque, Md. Jawad-Al-Mursalin
,
Mohammad, Nur
,
Shufian, Abu
in
Biomass
,
Capital costs
,
Climate change
2022
Distributed energy resources (DER) based microgrid system integration over conventional grids at remote or isolated locations has many potential benefits in minimizing the effects of global warming. However, this emerging microgrid technology brings challenges such as high capital costs, stable performance, uncertainties, operation, maintenance, and management issues. This research introduces an island microgrid system with a correlation of PV/wind/biomass/electrolyzer/hydrogen storage/fuel cell/diesel generator. The suggested hybrid system is assessed based on the different natural uncertainties of the DER, considering the availability of wind speed, solar irradiation, and biomass fuels. Optimized electricity production and possible economic interpretation of the microgrid system are revealed. Day-ahead forecast generation and load demand dispatch analysis related to various uncertainties are estimated and calculated by the net load demand forecasting approach. With the help of optimal power dispatch scheduling, the day-ahead generation and load demand uncertainties are effectively handled. A few plausible case studies bespeak the suitability of the suggested island microgrid system in different environmental situations where the national grid is unavailable. The real-time simulation of the proposed model amplifies the feasibility of generation synchronization with load demand.
Journal Article
Efficient digital implementation of a multi-precision square-root algorithm
by
Beasley, Alexander E.
,
Clarke, Christopher T.
,
Watson, Robert J.
in
Accuracy
,
Algorithms
,
Approximation
2019
In high performance computing systems and signal processing, there is a basic set of mathematical functions that are essential. While addition, subtraction and multiplication are well understood, there is less literature on square-rooting, which is a particularly time- and resource-consuming function. Traditional non-restoring algorithms produce a mantissa half the length of the input mantissa, causing a loss of precision. This study presents a method for increasing the accuracy of this algorithm. It is shown to work for all IEEE-754R standard floating-point numbers. Error analysis shows a 57-fold (for half-precision) and 134e6-fold improvement (for double-precision) in the normalised error, equivalent to at most 1 Units of Least Precision. Resource and performance optimised variants are analysed and their throughput analysed. On an Intel Stratix V device, performance optimised implementations achieve a throughput of 717 MFLOPs. Resource optimised implementations on a low-cost device require only 127 Adaptive Logic Modules and 232 registers, with a throughput of 8.56 MFLOPs. All implementations are DSP block and memory free, saving valuable resources. The maximum throughput of the presented design is 15.5 times greater than that proposed by Pimentel et al. and two orders of magnitude greater than typical multiply-accumulate methods.
Journal Article
The Effects of Pilot Structure on the Lean Ignition Characteristics of the Internally Staged Combustor
2025
In order to explore the influence of pilot structure on the lean ignition characteristics in a certain type of internally staged combustor, the current study was conducted on the effects of the auxiliary fuel nozzle diameter, the rotating direction of the pilot swirler, and the swirl number on the lean ignition fuel–gas ratio limit, combining numerical simulation and experimental validation. The optimization potential of the mixing structure of this type of internally staged combustor was further explored. It indicated that the lean ignition fuel–gas ratio limit was significantly influenced by the diameter of the auxiliary fuel nozzles the swirl number of the pilot swirler and the combination of the same rotating direction for both pilot swirlers, while the mass flow rate of air was constant. Increasing the diameter of the auxiliary fuel path nozzles (0.4~0.6 mm) and having excessively higher or lower swirl numbers of the pilot module primary swirlers are not conducive to broadening the lean ignition boundary. Compared with the two-stage pilot swirler with the same rotation combination, the fuel–gas ignition performance of the two-stage pilot swirler with the opposite rotation combination is better. Under the typical working conditions (the air mass flow rate is 46.7 g/s and the ignition energy is 4 J), for a pilot swirler with a rotating direction opposite to the main swirler, the diameter of the auxiliary fuel nozzles is 0.2 mm, the swirl number of first-stage of pilot swirler is 1.4, and the lean ignition fuel–air ratio was reduced to 0.0121, which is 32.78% lower than the baseline scheme, which further broadens the lean ignition boundary of the centrally staged combustion chamber.
Journal Article