Target Power Research Articles

Excellent Tribological Properties of WS2 Films in Air by Doping Copper

WS2 films exhibit excellent tribological properties in a vacuum, but they are prone to failure due to oxidation in air, which severely limits their application. Cu has great potential to improve the tribological properties of WS2, similar to that of Au and Ag. Thus, to clarify the contribution of Cu to the tribological properties of WS2 films and provide new insight for the development of new multi-environmentally adaptable films, this study deposited WS2-Cu composite films under different sputtering powers of the Cu target by magnetron sputtering systems, and the Cu target was supplied by DC power. Then, the structure of films was analyzed by FESEM, EDS and XPS. The results show that Cu is difficult to uniformly dope on the WS2 film at a high sputtering power of Cu target, showing possibly low solubility of Cu in WS2 film. However, a uniform and dense WS2-Cu composite film was deposited under the lower sputtering power of Cu target. Furthermore, the results of the nanoindentation test demonstrated that the WS2-Cu composite films exhibited high hardness (6.6 GPa). Finally, the tribological properties of the WS2-Cu films were examined, and their friction interface was characterized by SEM, EDS and TEM. The WS2-Cu film demonstrated superior tribological behavior in air (the average friction coefficient is 0.09), based on a special sliding interface, low oxidation levels of WS2 and Cu-rich transfer film. This study provides a new insight and a new method for improving the environmental adaptation ability of WS2 film.

TAD-SIE: sample size estimation for clinical randomized controlled trials using a Trend-Adaptive Design with a Synthetic-Intervention-Based Estimator

BackgroundPhase-3 clinical trials provide the highest level of evidence on drug safety and effectiveness needed for market approval by implementing large randomized controlled trials (RCTs). However, 30–40% of these trials fail mainly because such studies have inadequate sample sizes, stemming from the inability to obtain accurate initial estimates of average treatment effect parameters.MethodsTo remove this obstacle from the drug development cycle, we present a new algorithm called Trend-Adaptive Design with a Synthetic-Intervention-Based Estimator (TAD-SIE) that powers a parallel-group trial, a standard RCT design, by leveraging a state-of-the-art hypothesis testing strategy and a novel trend-adaptive design (TAD). Specifically, TAD-SIE uses synthetic intervention (SI) to estimate individual treatment effects and thereby simulate a cross-over design, which makes it easier for a trial to reach target power within trial constraints (e.g., sample size limits). To estimate sample sizes, TAD-SIE implements a new TAD tailored to SI given that using it violates assumptions under standard TADs. In addition, our TAD overcomes the ineffectiveness of standard TADs by allowing sample sizes to be increased across iterations without any condition while controlling significance level with futility stopping. Our TAD also introduces a hyperparameter that enables trial designers to trade off between accuracy and efficiency (sample size and number of iterations) of the solution.ResultsOn a real-world Phase-3 clinical RCT (i.e., a two-arm parallel-group superiority trial with an equal number of subjects per arm), TAD-SIE obtains operating points ranging between 63% to 84% power and 3% to 6% significance level in contrast to baseline algorithms that get at best 49% power and 6% significance level.ConclusionTAD-SIE is a superior TAD that can be used to reach typical target operating points but only for trials with rapidly measurable primary outcomes due to its sequential nature. The framework is useful to practitioners interested in leveraging the SI algorithm for their study design.

Fifteen-second bouts of hyperoxia improve 5-minute time-trial performance in acute hypoxic conditions

Introduction Hyperoxia, e.g. administration of 100 % oxygen, is a wide spread tool to improve blood oxygenation (e.g. in emergency medicine) but is also applied in elite sports to improve training intensity or competition performance. The positive effects of continuous hyperoxia during aerobic high-intensity exercise has been shown repeatedly, however, the potential effects of intermittent doses are unclear. Out study aimed to test the effects of repeated bouts of hyperoxia, each lasting fifteen seconds, on maximal 5-minute cycling performance under acute hypoxic conditions. Methods 17 healthy and recreationally trained individuals (7 females, 10 males, age 27 ± 4 years) participated in this randomized placebo-controlled cross-over trial. The procedures included a graded cycle ergometer test until exhaustion and three maximal 5-minute cycling time trials (TT). The peak power output during the maximal cycle ergometer test provided the basis for the determination of the target power output for the TTs. The subsequent TTs were conducted in a normobaric hypoxic chamber at the Department of Sport Science of the University Innsbruck (590 m). TT1 took place in normoxia and served for habituation and reference. TT2 and TT3 were conducted in normobaric hypoxia (15.0 % inspiratory fraction of oxygen, corresponding to about 3200 m simulated altitude). During TT2 and TT3 the participants were breathing through a face mask during five 15-second periods (0:20 to 0:35; 1:20 to 1:35; etc.). The face mask was connected via a non-rebreathing T-valve to a 300-litre bag filled with 100 % oxygen (intermittent hyperoxia condition) or ambient hypoxic air (placebo condition). Heart rate was recorded continuously during the TTs. Ratings or perceived exertion were recorded after test termination and capillary blood samples were taken from the hyperaemic earlobe 2 minutes later to analyze blood lactate concentrations. Arterial oxygen saturation was measured via finger pulse oximeter during a 60-second period (ca. minutes 2:00 to 3:00). Thereby, one 15-second hyperoxic intervention bout during the test in the intermittent hyperoxia condition was included. Main outcome was the mean power output during the TT. Statistical significance level was set at p < 0.05. Results Mean power output was higher in the intermittent hyperoxia compared to the placebo condition (255.5 ± 49.6 W versus 247.4 ± 48.2 W, p = 0.001). Blood lactate concentration and ratings of perceived exertion were significantly lower in the intermittent hyperoxia compared to the placebo condition (10.2 ± 1.7 mmol/L versus 11.3 ± 2.5 mmol/L and 17.8 ± 1.4 versus 19.2 ± 1.1 respectively). However, heart rate values were unchanged between conditions (168.0 ± 8.6 bpm versus 169.4 ± 10.3 bpm, p = 0.332). Arterial oxygen saturation increased by the 15-second application of hyperoxia (82.9 ± 2.6 % to 92.4 ± 3.3 %, p < 0.001). Conclusion Repeated 15-second bouts of hyperoxia, applied during high-intensity exercise in hypoxia, are sufficient to increase power output. Future studies should focus on potential dose-response effects and the involved mechanisms.

Analysis of the persistent photoconductivity in composite nanocrystalline ZnO/Si films produced by co-sputtering at room temperature

AbstractThe persistent photoconductivity (PPC) behavior in composite nanocrystalline films ZnO(RF)/Si(DC) films grown by co-sputtering was studied. The studied films were produced by fixing the ZnO RF magnetron power at 120 Watts and varying the DC power for the Si target from 0 to 80 Watts. The produced films were structural, optical, and electrical characterized; n-type films were produced for all the composition range. The PPC behavior was studied in samples grown with the composition formed with the ZnO (RF = 120 W)/Si (DC = 20 W) power condition, and by exposing the sample surfaces under continuous or pulsed ultraviolet (UV) radiation (390–400 nm). After applying an extended cleansing period, the PPC characteristic time constants, τ.63, were obtained; the turn-off time constant varied from 16.8 to 22.8 s, while the turn-on time constant changed from 24 to 30 s. These periods are linked to the UV light lattice absorption and the corresponding energy relaxation mechanisms. Graphical abstract

Mechanical property and biocompatibility of multilayer Ti-DLC films with different Ti target power by hybrid PVD/PECVD on 316L stainless steel

Mechanical property and biocompatibility of multilayer Ti-DLC films with different Ti target power by hybrid PVD/PECVD on 316L stainless steel

Integrated CNN‐LSTM for Photovoltaic Power Prediction based on Spatio‐Temporal Feature Fusion

ABSTRACTThe accurate prediction of the output power of each power plant is crucial for effective resource deployment. This paper proposes a convolutional neural network‐long short‐term memory (CNN‐LSTM) network integration model based on spatio‐temporal feature fusion. Firstly, the temporal correlation of the PV features of the target power plant and the spatial correlation between the PV power of the target power plant and the PV power of the neighboring power plants are computed. The features are then fused according to the strength of the correlation, which allows the features to be combined with spatial and temporal attributes, which promotes faster and more effective training of the model. Subsequently, an integrated network architecture comprising three individual models, CNN, LSTM, and CNN‐LSTM, is designed. The SENet attention mechanism is utilized to add non‐linear integration weights to the outputs of the individual models. Due to the variability of different neural networks, the prediction results of the integrated model are often higher than the best‐performing individual model. Additionally, we designed different case studies to compare model performance under sunny, rainy, and cloudy conditions. Extensive simulation experiments demonstrate the effectiveness of our proposed integrated approach. When the prediction interval is set to 5 min, the RMSE loss of the integrated model on the test set is reduced by 13.5%, 6.9%, and 5.1% compared to the CNN, LSTM, and CNN‐LSTM models included in the ensemble, respectively.

Flexible Spline Models for Blinded Sample Size Reestimation in Event-Driven Clinical Trials.

In event-driven trials, the target power under a certain treatment effect is maintained as long as the required number of events is obtained. The misspecification of the survival function in the planning phase does not result in a loss of power. However, the trial might take longer than planned if the event rate is lower than assumed. Blinded sample size reestimation (BSSR) uses non-comparative interim data to adjust the sample size if some planning assumptions are wrong. In the setting of an event-driven trial, the sample size may be adjusted to maintain the chances to obtain the required number of events within the planned time frame. For the purpose of BSSR, the survival function is estimated based on the interim data and often needs to be extrapolated. The current practice is to fit standard parametric models, which may however not always be suitable. Here we propose a flexible spline-based BSSR method. Specifically, we propose to carry out the extrapolation based on the Royston-Parmar spline model. To compare the proposed procedure with parametric approaches, we carried out a simulation study. Although parametric approaches might seriously over- or underestimate the expected number of events, the proposed flexible approach avoided such undesirable behavior. This is also observed in an application to a secondary progressive multiple sclerosis trial. Overall, if planning assumptions are wrong this more robust flexible BSSR method could help event-driven designs to more accurately adjust recruitment numbers and to finish on time.

Benchmarks of Success in Radiotherapy versus Systemic Therapy National Clinical Trials Network (NCTN) Randomized Controlled Trials Sponsored by the National Cancer Institute (NCI).

The National Clinical Trials Network (NCTN) is the largest government sponsored organization in the United States tasked with funding randomized controlled trials (RCTs) in oncology. It is unknown whether there are differences in study design by treatment modality. We evaluated differences in methodology between trials testing radiotherapy versus systemic therapy. The Clinical Trials Support Unit website was used to identify active RCTs of systemic or radiotherapy across NCTN cooperative groups through December 31, 2023. Studies in disease sites with > 5 radiotherapy trials were included. Each trial's protocol was reviewed to obtain key design information that were descriptively compared: primary endpoint, hypothesis testing type (superiority vs non-inferiority), non-inferiority margin, hypothesized effect size, power, and significance level. A total of 186 RCTs (142 systemic therapy, 44 radiotherapy) were examined. Comparing primary endpoints, 59.1% vs 26.8% of radiotherapy vs systemic therapy trials, respectively, had a primary endpoint of overall survival. Nearly 1/3 of radiotherapy trials (31.2%) were non-inferiority vs 6.3% of systemic therapy trials. Among breast cancer trials, 75% of radiotherapy studies were non-inferiority vs 11.1% systemic. Target effect size, power, and significance level were similar by treatment modality within tumor types and disease settings. Among NCTN cooperative group RCTs, there were marked differences in study design between radiotherapy vs systemic therapy trials. A higher benchmark for defining success for radiotherapy interventions was observed with greater emphasis on overall survival as primary endpoint. This may reflect differences in therapeutic mechanism by modality and types of study questions posed.

Effects of target power and deposition pressure on magnetron-sputtered molybdenum disulfide thin films: Morphological, structural, optical, and electrical characteristics

Effects of target power and deposition pressure on magnetron-sputtered molybdenum disulfide thin films: Morphological, structural, optical, and electrical characteristics

Surface Ionic Conduction of Ce0.8Gd0.2O2-Δ Multilayer Thin Films with Large Amount of Oxygen Vacancies

Gd-doped CeO2 (GDC) with high chemical stability is a good electrolyte material with high oxygen ion conduction above 600°C and surface proton conduction below 100°C in thin film form [1]. In particular, Ni-GDC cermet material is well known as anode electrode of solid oxide fuel cell (SOFC) operating at medium temperature region. Ni is suitable for the anode as it has the characteristics of being inexpensive and having high catalytic activity, which enhances the hydrogen oxidation reaction. Ni is characterized by its low cost, high catalytic activity, and enhanced hydrogen oxidation reaction. Mixtures of electronic conductors such as Ni and ionic conductors such as Yttria-stabilized zirconia (YSZ) and GDC are often used as anode materials because they expand the three-phase interface [2].Based on these backgrounds, we have attempted to realize high conductivity in GDC (Ce0.90Gd0.10O2-δ) thin films, which contain a large amount of oxygen vacancies and lattice distortion. if the GDC films show high ionic conductivity above σ T~10-1Scm-1K, the performance of SOFCs and EDLTs will be dramatically improved. performance of SOFC and EDLT will be dramatically improved. To realize this goal, thin films were prepared by sputtering method, the relationship between surface defect structure and ionic conductivity was investigated in detail, and electrodes were fabricated on the thin films with Pt and Ni thin films.Based on these backgrounds, in this study, we tried to realize high conductivity by fabricating electrodes with Ni thin films on GDC (Ce0.90Gd0.10O2- δ) with large amount of oxygen vacancies and lattice distortion. If the GDC thin films show high ionic conductivity above σ T~10-1Scm-1K, the performance of SOFCs and EDLTs will improve dramatically. In order to realize this purpose, we fabricated thin films by the sputtering method and studied in detail the relationship between the surface defect structure and ionic conductivity.The GDC thin films were prepared on Al2O3 (0001) substrates by RF magnetron sputtering using ceramic targets. The target size had a diameter of 47 mm and thickness of 3 mm. The RF power of the ceramic target was fixed at 30 W. The flow rate of Ar gas controlled by a mass-flow controller was kept at approximately 2.81 ccm. The pressure of Ar gas was fixed at 3.5 × 10−3 Torr during the deposition. The film thicknesses ~30 and ~110 nm to probe the changes in the lattice constant and the conductivity. The electrode film was fabricated on the GDC thin film using a similar method with Pt and Ni metal targets. Electrical conductivity was measured by the AC impedance method. The measurement range was 600 °C to 20 °C. The result when only Ar was filled at the time of measurement is called As-deposited, and the result when a 4:1 mixture of Ar and gases was filled at the time of measurement is called -annealed.Arrhenius plots at low temperatures below 100 °C are shown in Fig. The thin films with Pt electrode are designated as Pt-GDC and those with Ni electrode as Ni-GDC. The PES spectra show that the OH- peak appears after Wet annealing. Therefore, it can be said that surface proton conduction by the Grotthuss mechanism is taking place [3]. In comparison for Pt-GDC, the O2 annealed condition resulted in higher conductivity than the As-deposited condition. This is thought to be due to the reduction of oxygen defects in the thin film by O2 annealing and the dominance of proton conduction. Ni-GDC resulted in lower conductivity than Pt-GDC under the two conditions. For Ni-GDC, there are reports that the peak power density varied with the voltage at the time of deposition [4], that ohmic resistance decreased by moderately thickening the anode and that the power density was highest at 800 nm thickness [4], and that the oxygen reduction reaction at the cathode was promoted by the grain boundaries and lattice defects report [5] that grain boundaries and lattice defects promote the oxygen reduction reaction at the cathode.Reference[1] M, Shirpor et al. Phys. Chem. Chem. Phys., 13 (2011) 937-940.[2] I.D. Unachukwu et al. Journal of Power Sources 556 (2023) 232436[3] D. Nishioka et al, Nanoscale Res. Lett. 15 (2020) 42-49[4] S, Ryu et al. ACS Appl. Mater. Interfaces 2023, 15, 11845−11852[5] Y, Li et, al, Scientific Reports 6, 22369 (2016) Figure 1

Tungsten interior doping engineering induced sulfur vacancies of MoS2 for efficient charge transfer and nonlinear optical performance: Implications for optical limiting devices

Modulating the photoelectric properties of molybdenum disulfide (MoS2) through defect engineering and heterometal doping is crucial for its potential applications in electronic and optoelectronic devices. Herein, a comprehensive overview is provided on the advancements of two-dimensional materials with a ternary structure comprising sulfur (S), molybdenum (Mo), and tungsten (W) in the field of optoelectronic device. A ternary W-P/MoS2 (P: direct current target power) nanomaterial was designed and synthesized using W interior doping engineering induced S vacancies. The experimental results reveal that the introduction of W metal causes lattice distortion in MoS2, leading to the formation of S vacancies within W-P/MoS2. Compared to pure MoS2, W-P/MoS2 with S vacancies demonstrates enhanced reverse saturable absorption and optical limiting. Density functional theory calculations suggest that the S vacancies introduced by W doping in MoS2 introduce defect energy levels, which are believed to be the reason for the improved nonlinear optical (NLO) performance of W-P/MoS2. Furthermore, transient absorption spectroscopy reveals the photophysical model of carrier relaxation and presents an explanation for the optimized NLO properties of W-P/MoS2. This work provides a novel strategy for the design and synthesis of ternary transition metal dichalcogenides and modulating the NLO properties by doping transition metal-mediated vacancies.

Advances in Room Temperature of Indium Aluminum Nitride InAlN Deposition via Direct Current (DC) Co-Sputtering for Solar Energy Applications

This study presents an innovative method for the synthesis of indium aluminum nitride (InAlN) layers by direct current (DC) co-sputtering at room temperature, with the aim of reducing production costs of optoelectronic devices. Indium and aluminum targets are used, varying the power applied to the aluminum target. The results show that increasing the target power favors the formation of aluminum nitride (AlN), which modifies the chemical composition of the material. The layers obtained present smooth surfaces with a roughness of less than 3 nm, which is beneficial for applications requiring interfaces with low defect density. Regarding the optical properties, it is observed that the optical bandgap varies between 1.8 eV and 2.0 eV, increasing with the target power. Hall effect measurements indicate a decrease in the free carrier concentration and an increase in the resistivity with increasing power. This approach allows for the synthesis of InAlN with properties suitable for optoelectronic applications, solar cells, photocatalysis, and photoelectrocatalysis at low cost.

Experimental research on the TCV tokamak

Abstract Tokamak à configuration variable (TCV), recently celebrating 30 years of near-continual operation, continues in its missions to advance outstanding key physics and operational scenario issues for ITER and the design of future power plants such as DEMO. The main machine heating systems and operational changes are first described. Then follow five sections: plasma scenarios. ITER Base-Line (IBL) discharges, triangularity studies together with X3 heating and N2 seeding. Edge localised mode suppression, with a high radiation region near the X-point is reported with N2 injection with and without divertor baffles in a snowflake configuration. Negative triangularity (NT) discharges attained record, albeit transient, β N ∼ 3 with lower turbulence, higher low-Z impurity transport, vertical stability and density limits and core transport better than the IBL. Positive triangularity L-Mode linear and saturated ohmic confinement confinement saturation, often-correlated with intrinsic toroidal rotation reversals, was probed for D, H and He working gases. H-mode confinement and pedestal studies were extended to low collisionality with electron cyclotron heating obtaining steady state electron iternal transport barrier with neutral beam heating (NBH), and NBH driven H-mode configurations with off-axis co-electron cyclotron current drive. Fast particle physics. The physics of disruptions, runaway electrons and fast ions (FIs) was developed using near-full current conversion at disruption with recombination thresholds characterised for impurity species (Ne, Ar, Kr). Different flushing gases (D2, H2) and pathways to trigger a benign disruption were explored. The 55 kV NBH II generated a rich Alfvénic spectrum modulating the FI fas ion loss detector signal. NT configurations showed less toroidal Alfvén excitation activity preferentially affecting higher FI pitch angles. Scrape-off layer and edge physics. gas puff imaging systems characterised turbulent plasma ejection for several advanced divertor configurations, including NT. Combined diagnostic array divertor state analysis in detachment conditions was compared to modelling revealing an importance for molecular processes. Divertor physics. Internal gas baffles diversified to include shorter/longer structures on the high and/or low field side to probe compressive efficiency. Divertor studies concentrated upon mitigating target power, facilitating detachment and increasing the radiated power fraction employing alternative divertor geometries, optimised X-point radiator regimes and long-legged configurations. Smaller-than-expected improvements with total flux expansion were better modelled when including parallel flows. Peak outer target heat flux reduction was achieved (>50%) for high flux-expansion geometries, maintaining core performance (H 98 > 1). A reduction in target heat loads and facilitated detachment access at lower core densities is reported. Real-time control. TCV’s real-time control upgrades employed MIMO gas injector control of stable, robust, partial detachment and plasma β feedback control avoiding neoclassical tearing modes with plasma confinement changes. Machine-learning enhancements include trajectory tracking disruption proximity and avoidance as well as a first-of-its-kind reinforcement learning-based controller for the plasma equilibrium trained entirely on a free-boundary simulator. Finally, a short description of TCV’s immediate future plans will be given.

The Elevated Temperature Tribological Performance of Tough and Superhard TaMoN-Ag films with Solute and Nanocomposite Structures

Abstract Films have been prepared with not only high hardness to guarantee excellent wear resistance but also high toughness to prevent brittle fracture at low to middle-high temperatures. On the basis of ternary transition metal nitrides with significantly improved hardness and toughness, TaMoN-Ag films with solute and nanocomposite structure were prepared by DC magnetron sputtering technology. Friction wear tests were performed between room temperature (RT) and 700 °C. When doping with trace amounts of Ag atoms (∼1.12 at.%, 4 W), TaMoN-Ag films maintain solid solution structure. TaMoN-Ag films with the Ag target power is 4 W show the highest hardness (H∼62.1 GPa), which is 58% higher than TaMoN film and 44% better than that of TaMoN films. Meanwhile, a lower wear rate (KIC∼5.87×10-7 mm3/N·m) is obtained. The tribological properties of TaMoN-Ag films at room temperatures are related to the H3/E2 and lubricious Ag phase, while the tribological properties at high temperatures are mainly due to the formation of lubricating binary metal oxides (AgxTMyOz (Magnéli phases)). The composite films generally have good resistance to plastic deformation.

A Fuzzy Adaptive PID Coordination Control Strategy Based on Particle Swarm Optimization for Auxiliary Power Unit

Range extender hybrid vehicles have the advantages of better dynamics and longer driving range while reducing pollution and fuel consumption. This work focuses on the control strategy of an Auxiliary Power Unit (APU) operating in power generation mode for a range-extender mixer truck. When an operating point is switched, the engine speed and generator torque of the APU will switch accordingly. In order to ensure APU fast and stable adjustment to meet the power demand of the vehicle as well as operate at the lowest fuel consumption, a fuzzy adaptive PID coordination control strategy based on particle swarm optimization (PSO) is proposed to control the APU. The optimal operating curve of APU is calculated by coupling the engine and generator first. Then, the adaptive PID algorithm is used to control the speed and torque of the APU in a dual closed loop. The PSO is used to optimize the PID control parameter. Through hardware-in-the-loop tests under different working conditions, the control strategy is verified to be effective and real-time. The results show that the proposed control strategy can coordinate the operating of engine and generator and control the APU to track target power stably and quickly under minimum fuel consumption. Compared with traditional PID control strategy, the overshoot, regulation time and steady-state error are reduced by 55.1%, 11.1% and 77.3%, respectively.

Evolution of TiAlSi thin film coatings under varying target power in DC magnetron sputtering

This study, for the first time, presents the growth, nucleation, and characteristics of TiAlSi thin films sputtered from a partially sintered Ti30Al16Si10 (at. %) composite target under controlled conditions of target power. The TiAlSi thin films were grown on soda-lime glass substrates through Direct Current (DC) sputtering at varying levels of the target power: 73.2 W, 151.2 W, and 269.5 W. The other deposition parameters: the deposition temperature, time, argon mass flow rate, substrate rotation, and deposition pressure, were kept constant at 23 °C, 150 min, 25 sccm, 5 rpm, and 10−3 mbar, respectively. The pre-sputter power, argon flow rate, and time were also kept constant at 73.2 W, 20 sccm, and 5 min, respectively. The physical properties, microstructure, crystal structure, topography, and mechanical properties of the thin film coatings were analysed. The thickness and rate of deposition of the TiAlSi thin films increased with an increase in the target power (73.2 W – 269.5 W) from 414.6 nm and 0.046 nm/s to 1358.8 nm and 0.151 nm/s, respectively. The chemical composition of all the thin films remained constant, with the formation of a uniform TiAlSi alloy with no segregation of elements. However, a thin (wetting) interlayer consisting of Si and O elements was observed between the TiAlSi layer and the glass substrate. Further, the structure sizes and roughness values of the TiAlSi thin films increased with an increase in the target power, with a maximum of 75.4 nm for the size and 4.78 nm for the RMS roughness of thin films deposited at the maximum target power (269.5 W). Lastly, mechanical analysis of the TiAlSi thin films depicted an increase in the hardness as the target power increased, with the highest hardness at maximum power (269.5 W) obtained as 4.76 GPa. Despite having the lowest elastic modulus (50.5 GPa), the coating deposited at the highest power exhibited the highest plasticity index (H/E) and plastic deformation factor (H3/E2) of 0.094 and 0.042 GPa, respectively, which indicated the high resistance to abrasive wear, cracking, and deformation, compared to thin films deposited at the lowest target power (H/E = 0.066 and H3/E2 = 0.015 GPa). This study demonstrates that target power is a significant factor in determining the growth of TiAlSi thin films during the sputtering process and can be used for better control of their physical, structural, and mechanical properties.

Microstructure, mechanical and tribological characterization of magnetron sputtering ZrN and ZrAlN coatings

In this research paper, mechanical and tribological characterization of novel high wear-resistant ZrN-ZrAlN coatings are presented. The varying concentrations of AlN is chosen to evaluate the influence of AlN the surface morphological, nanomechanical, and tribological properties of the composite coating. The coatings were developed on D9 steel substrates using nitrogen reactive gas radio frequency (RF) magnetron sputtering of zirconium and aluminium targets in an argon plasma. Variable power density for the aluminium target and constant power density for zirconium, was used to obtain in a systematic way, the variable concentration of AlN in the coating. Surface morphological studies were carried out to evaluate composition and crystal structure using X-ray diffraction (GIXRD), Raman spectroscopy, and energy-dispersive X-ray spectroscopy (EDS). Coatings display a polycrystalline structure, but the level of crystallinity decreases with higher AlN concentration. Nanomechanical and nano scratch testing, along with tribological experimental studies were performed to comprehensively analyse performance of the developed coatings. Higher hardness of composite coating is achieved with optimal concentration of AlN in ZrN-ZrAlN coating. Adhesion strength of the coatings increased with the increase in the concentration of AlN. ZrN-ZrAlN coatings depicted low wear, however coatings containing AlN exhibits superior wear resistance.

Experimental and numerical studies on performance investigation of a diesel engine converted to run on LPG

With the growing environmental concerns and depletion of energy resources, considerable efforts are focused on developing ecofriendly and sustainable transportation systems. This includes the conversion of outdated diesel engines into ecofriendly liquefied petroleum gas (LPG) engines. In this study, a Euro-6 diesel engine mounted on a commercial vehicle (mega truck) was converted into a propane LPG engine. The combustion chamber was modified by changing the piston shapes (PSs), compression ratios (CRs), ignition system, throttle body, and injector design to enable operation using propane. The performance of the modified engines with two different PSs, PS1 and PS2, were experimentally investigated. In terms of the power, the engine designed using PS2 demonstrated better performance than PS1 under all operating speeds, except 2600 rpm. Particularly, PS2 outperformed PS1 by more than 10 Nm in the low-speed range of 1000–1600 rpm. Under full load, the PS2-equipped LPG engine achieved the maximum torque and power of 834 Nm at 1600 rpm and 170 kW at 2600 rpm, achieving 106 % and 86 % of the target torque and power, respectively. Additional exhaust gas emission tests were performed using the PS2-equipped LPG engine. The engine performance varied with the application of exhaust-gas recirculation. Moreover, the results of the world-harmonized stationary cycle mode tests confirmed the conformance of the modified LPG engine to all Euro-6 emission standards. Furthermore, simulation-based performance optimization was conducted considering two PSs and four CRs. Based on the simulations, PS1 achieved higher engine performance and lower CO2 and soot emissions, whereas PS2 had lower NO emissions. Additionally, increasing the CR improved the performance and reduced the CO2 and soot emissions for both PSs. These results indicate the possibility of developing LPG engines with performance comparable to diesel engines. In particular, the modified LPG engine proposed in this work may be installed on buses and trucks in the future and is anticipated to replace outdated medium-generator and marine engines.

Power-Law Scaling Relating the Average Charge State and Kinetic Energy in Expanding Laser-Driven Plasmas.

A universal power-law scaling z[over ¯]∝E^{0.4} in the correlation between the average ion charge state z[over ¯] and kinetic energy E in expanding laser-driven tin plasmas is identified. Universality here refers to an insensitivity to all experimental conditions: target geometry, expansion direction, laser wavelength, and power density. The power law is accurately captured in an analytical consideration of the dependence of the charge state on temperature and the subsequent transfer of internal to kinetic energy in the expansion. These analytical steps are individually, and collectively, validated by a two-dimensional radiation-hydrodynamic simulation of an expanding laser-driven plasma. This power-law behavior is expected to hold also for dense plasma containing heavier, complex ions such as those relevant to current and future laser-driven plasma light sources.

Insight into the Structural and Performance Correlation of Photocatalytic TiO2/Cu Composite Films Prepared by Magnetron Sputtering Method

Photocatalysis technology, as an efficient and safe environmentally friendly purification technique, has garnered significant attention and interest. Traditional TiO2 photocatalytic materials still face limitations in practical applications, hindering their widespread adoption. The research prepared TiO2/Cu films with different Cu contents using a magnetron sputtering multi-target co-deposition technique. The incorporation of Cu significantly enhances the antibacterial properties and visible light response of the films. The effects of different Cu contents on the microstructure, surface morphology, wettability, antibacterial properties, and visible light response of the films were investigated using an X-ray diffractometer, X-ray photoelectron spectrometer, field emission scanning electron microscope, confocal laser scanning microscope, Ultraviolet–visible spectrophotometer, and contact angle goniometer. The results showed that the prepared TiO2/Cu films were mainly composed of the rutile TiO2 phase and face-center cubic Cu phase. The introduction of Cu affected the crystal orientation of TiO2 and refined the grain size of the films. With the increase in Cu content, the surface roughness of the films first decreased and then increased. The water contact angle of the films first increased and then decreased, and the film exhibited optimal hydrophobicity when the Cu target power was 10 W. The TiO2/Cu films showed good antibacterial properties against Escherichia coli and Staphylococcus aureus. The introduction of Cu shifted the absorption edge of the films to the red region, significantly narrowed the band gap width to 2.5 eV, and broadened the light response range of the films to the visible light region.