Energy Coefficient Research Articles

Stimulated Brillouin scattering in plasmonic nanofiber containing an ensemble of metallic nanorods

A theory of stimulated Brillouin scattering (SBS) has been developed for metallic nanohybrid fiber, which is made of an ensemble of metallic nanoparticles doped in a dielectric nanofiber. We consider that input probe light photons scatter within the nanohybrid and produce stimulated Brillouin scattered photons and acoustic phonons. The coupled-mode formalism based on Maxwell’s equations is used to obtain the SBS intensity, the SBS energy, and the SBS absorption coefficient. It is found that the SBS depends on the third-order susceptibility, which is evaluated by the density matrix method. An analytical expression of the SBS intensity, energy, and absorption coefficient is calculated in the presence of surface plasmon polaritons (SPPs) and dipole-dipole interactions (DDI) between nanoparticles in the ensemble. Next, we have compared our theory with the experimental data for a nanohybrid made of an ensemble of Au-nanorods doped in water. A good agreement between theory and experiment is found. We have also performed the numerical simulations to study the effect of SPP and DDI fields on the SBS intensity. We have predicted an enhancement in the SBS intensity due to the SPP and DDI couplings. The enhancement is due to not only the scattering mechanisms of the probe photons with acoustic phonons but also the extra scattering mechanisms from the SPP and DDI polaritons with acoustic phonons. The SBS analytical expressions can be useful for experimental scientists and engineers who can use them to plan new experiments and make new types of plasmonic devices. The enhancement effect can be used to fabricate new types of SBS nanosensors and amplifiers.

Multi-bolt looseness monitoring using guided waves: a cross-correlation approach of the wavelet energy envelope

Abstract This paper proposes a novel approach for monitoring multi-bolt looseness using guided waves and the cross-correlation of the wavelet energy envelope. By assessing variations in the wave packet, the looseness in multi-bolt assemblies can be estimated. First, the dispersion effects of Lamb waves were theoretically analyzed using the Rayleigh-Lamb equation. Next, the wavelet energy was derived through wavelet transform, and the Lamb wave envelope was obtained as a criterion for accurately separating the wave packet. Cross-correlation analysis was employed to quantitatively evaluate the dispersion of wave packets for varying levels of bolt looseness. A looseness index, termed the normalized decorrelation coefficient of wavelet energy (NDCWE), was defined. Then, validation experiments were conducted using a joint with five M8 bolts, each tightened to a standard torque of 42 N·m. Two piezoelectric transducers were attached to the periphery of the bolt group. Three preload conditions were tested for each bolt: fully tightened, 80% of the standard torque, and 10% of the standard torque, corresponding to no looseness (NL), minor looseness (ML), and significant looseness (SL), respectively. Results showed that when significant looseness occurs, the NDCWE value exceeds 0.4, confirming the effectiveness of NDCWE in detecting substantial reductions in bolt preload. Experiments assessing the effect of temperature revealed that temperature has a negligible effect on the waveforms of the S0 and A0 mode waves. Finally, to quantitatively evaluate the efficiency of the ultrasonic transducers, the bolt-to-sensor ratio (BSR) was introduced. In this study, the BSR reached 2.5, indicating that a single piezoelectric transducer can monitor the preload of 2.5 bolts. The proposed approach shows great potential for multi-bolt looseness monitoring.

The Coefficient of Reactivity and Activation Energy as the Criteria of Assessment of the Influence of Sustainable Aviation Fuels on Combustion Process in a Rapid Compression Combustion Machine and a Turbine Engine

Aviation in Europe is required to use fuels containing up to 2 wt. % of sustainable aviation fuels (SAFs). A better understanding of the impact of SAFs on the combustion process will be helpful in solving problems that may arise from the widespread use of these kinds of fuels. It was assumed that the reactivity coefficient αi and the activation energy could be a criteria for assessing the impact of SAFs on the combustion process. Based on DGEN engine tests, the following activation energy values of CO2 and CO formation reactions were obtained—Jet A-1: EaCO2/R=3480 and EaCO/R=982; A30: EaCO2/R=3705 and EaCO/R=2903; and H30: EaCO2/R=3637 and EaCO/R=2843. These results indicate differences in the structure of combustion reaction chains involved by the SAF addition to Jet A-1 fuel. The same conclusion has been formulated on the basis of the reactivity coefficient αi. The values of maximum cylinder pressure (Pmax) obtained during indicator RCCM (rapid compression combustion machine) tests correlated with both the activation energy and coefficients of reactivity. This suggests that the influence of SAF addition to Jet A-1 fuel on the structure of chemical reactions chain during RCCM tests is similar to the influence during DGEN 380 tests. The assumption stated above was confirmed. This indicates the possibility of the preliminary forecasting of CO2 and CO emissions from the DGEN 380 engine based on the test at the RCCM stand.

Thermally-induced diffusion and structural phase transitions in Pt/Mn and Pt/Mn/Pt thin films

We demonstrate the possibility of diffusion formation of the chemically ordered L1 0-MnPt phase through the vacuum annealing of Pt(24 nm)/Mn(20 nm) and Pt(12 nm)/Mn(20 nm)/Pt(12 nm) layered stacks at 400 °C for 30 min. For the bi-layered stack annealed at 400 °C, the effect of Pt atoms segregation at the film/substrate interface was detected, which remained after annealing even at higher temperatures (500 °C and 600 °C) and prevented the whole homogenization of the chemical composition through the film depth. By contrast, for the tri-layered stack annealed at 400 °C, the presence of the additional Pt bottom layer enabled to change the rate and mechanism of reactive diffusion, leading to homogeneous distribution of components and enhanced crystallinity of the ordered L1 0-MnPt phase compared to the bi-layered sample. An explanation of the obtained experimental data is provided based on the fundamentals of mass transfer theory and its quantitative parameters (e.g. activation energy and diffusion coefficients).

Effects of temperature and drought stress on the seed germination of a peatland lily (Lilium concolor var. megalanthum).

Sexual reproduction through seeds is an effective way to renew plant populations and increase their genetic diversity, but seed germination process is complicated and relatively difficult due to the restriction of environmental conditions. Wetland plants that reproduce sexually through seeds may be affected by changes in moisture and temperature. This study aims to explore the ecological adaptation strategies of seed germination of Lilium concolor var. megalanthum under different hydrothermal conditions. Controlled experiments were conducted to investigate the germination performance of L. concolor var. megalanthum seeds at different temperatures (10°C, 15°C, 20°C, 25°C, and 30°C) and simulated drought stress conditions using PEG-6000 solutions (0%, 5%, 10%, 15%, and 20%). The results showed that temperature, drought stress, and their interaction significantly affected the days to first germination, germination percentage, coefficient of germination rate, germination energy, germination index, and vigor index of seeds (p<0.01). The germination percentage, germination index, and vigor index of seed were significantly higher at 25°C compared to other temperatures (p<0.01). The interaction between low temperature and drought stress significantly delayed the days to first germination. The inhibition of drought stress on seed germination was enhanced by PEG-6000 solution under high temperature. Under the conditions of 25°C and 5% PEG-6000 solution concentration, seeds of L. concolor var. megalanthum exhibited optimal germination parameters. At 10°C and 15°C, the seeds exhibited the highest tolerance to PEG-6000-simulated drought stress. Rehydration germination results showed that extreme temperatures and drought stress conditions inhibit seed germination of L. concolor var. megalanthum without damaging seed structure. The germination pattern of seeds under variable temperature and drought stress conditions reflects their adaptive strategies developed over long-term evolution to cope with the environmental conditions.

Effect of an external axial magnetic field on thermal convection of an electric conducting fluid in a rotating spherical shell

We investigated the interaction between the thermal convection structure in a rotating spherical shell and a uniformly applied magnetic field acting externally toward the axis of rotation. We considered a system that the inner and outer spherical boundaries are heated and cooled both isothermally and the effects of induced magnetic fields are neglected. The convection structure of this system is characterized by the generation of travelling waves around the axis of rotation. We numerically investigated how this is affected under the magnetic field. The characteristics of the disturbance (i.e., growth rate and phase velocity) were estimated from the exponential amplification period using three-dimensional (3D) simulations and compared with those obtained from linear stability analyses (LSA). In particular, the effects of the magnetic field on the kinetic energy and Nusselt number were investigated for a quasi-steady state using 3D simulations. Our numerical results revealed that the applied magnetic field destabilizes the flow field and enhances heat transfer. This is noteworthy, contrary to the common sense that magnetic field stabilizes the flow field and reduces the heat transfer coefficient. However, the magnetic field strengths at which the kinetic energy and heat transfer coefficient took their maximum values differ slightly.

Phase-field modeling of facet growth of diamond using a modified anisotropic coefficient of interfacial energy

In the present work, a modified anisotropic coefficient of interfacial energy is used to simulate the anisotropic facet crystal growth along non-orthogonal directions by phase-field method. The modified anisotropic coefficient of interface anisotropy is simulated and evaluated against the theoretical prediction of equilibrium shape. The simulation results are compared between the modified form and classic form. Subsequently, the modified anisotropic coefficient is employed to simulate the Wulff construction of facet growth of diamond, encompassing both pristine diamond and diamond with reconstructed surfaces. The dynamics of diamond morphology and the reconstructed surface area and proportion are thoroughly evaluated, demonstrating agreement with experimental records. The effect of the reconstruction surface on the growth of diamond grain is analyzed in terms of the total energy reduction, and the range of interfacial energies for more stable diamond reconstructions is also summarized. By introducing the modified anisotropic coefficient, anisotropic facet growth can be described and the simulation results are verified both theoretically and experimentally.

A blend of bacillus-fermented soybean meal, functional amino acids, and nucleotides improves nutrient digestibility, bolsters immune response, reduces diarrhea, and enhances growth performance in weaned piglets.

This study investigated the effects of a blend of bacillus-fermented soybean meal, functional amino acids, and nucleotides (Functional protein blend-FP Blend) as a replacement for animal protein sources in a weaner pig diet without antibiotic growth promoters on nutrient digestibility, blood profiles, intestinal morphology, diarrhea incidence, and growth performance. A total of 288 crossbred weaned piglets [♂ Duroc x ♀ (Yorkshire × Landrace)] with an average body weight (BW) of 6.89 ± 0.71kg were randomly allocated to 6 groups based on initial BW and sex (8 replicate pens per treatment; 3 gilts and 3 barrows/pen). The experiment lasted for 5wk. Dietary treatments included PC [standard diet with 3% fish meal (FM) and 2% plasma protein (PP)], NC (nonanimal protein, AP), T1 (3% FM replaced with 5% FP Blend), T2 (3% FM and 1% PP replaced with 5% FP Blend), T3 (2% PP replaced with 5%FP Blend), and T4 (3% FM and 2% PP replaced with 5% FP Blend). Data were analyzed using Minitab version 17 software. Key results indicated that FP Blend improved the apparent ileal digestibility (AID) coefficient of dry matter, gross energy, lysine, and valine in T4 compared with NC treatment (P < 0.05), whereas AID coefficient of crude protein and other amino acids remained constant (P > 0.05). Compared with NC diet, the weaned pigs fed T4 diet reduced malondialdehyde, serum IL8, TNF-α, and increased IgG (P < 0.05), while showing no effect on serum IL6, IL10, white blood cells, IgA, and endotoxin (P > 0.05). Furthermore, FP blend significantly increased villus height in the duodenum and ileum in T4 compared with NC (P < 0.05). The average daily gain (ADG) was highest in T4 (502.73g/d), followed by T1 (477.96g/d) and T2 (475.85g/d), compared with PC (450.86g/d) and NC (439.79g/d). T4's ADG significantly differed from PC and NC (P < 0.001), whereas no significant differences were observed in T1, T2, and T3 (P > 0.05). The feed conversion ratio (FCR) was significantly lower in T4 (1.45) compared with PC (1.57) and NC (1.59) (P < 0.001), with no significant differences among other groups. In conclusion, FP Blend demonstrated efficacy in improving nutrient digestibility, optimizing intestinal morphology, bolstering immune responses, reducing diarrhea incidence, alleviating the adverse effects of weaning stress, and enhancing growth performance of weaned piglets.

Full-fat black soldier fly larvae meal and yellow mealworm meal: Impact on feed protein quality, growth and nutrient utilization of Atlantic salmon (Salmo salar) post smolts

The shift towards insect-based alternatives in aquafeeds stems from the need to reduce the carbon footprint associated with the ingredients used in salmon feeds. In the present study, we describe the effects of full-fat insect meal incorporation on amino acid derivatives in feeds and the growth performance and nutrient utilization of Atlantic salmon post-smolts fed insect meals. A 74-day growth trial was conducted employing 520 fish (143 ± 12.8 g); these fish were fed either a control diet (CO) that contained 20 % fishmeal, 20 % soy protein concentrate (SPC), 14 % wheat gluten, 19 % plant raw materials, 13 % fish oil and 6 % rapeseed oil, or one of four insect meal diets, prepared with either 5 % and 10 % black soldier fly larvae meal (BS5, BS10) or 15 % and 30 % mealworm meal (MW15, MW30), by substituting mainly SPC, wheat gluten and rapeseed oil. The inclusion levels of BS and MW were determined based on their distinct chemical compositions, specifically their lipid content. As regards the results, HPLC-based high-throughput data on amino acid derivatives revealed the following: carboxymethyllysine was significantly higher in the MW30 feed than in BS5, BS10 and MW15 feeds; carboxyethyllysine was higher in the MW15 and MW30 feeds compared to the others; furosine was lower in the MW15 feed compared to the CO, BS5 and MW30 feeds. Regarding the effect of the insect meals on Atlantic salmon post-smolts, their inclusion had no significant effect on feed conversion ratio, health indicators and the retention efficiency of macronutrients. Apparent digestibility coefficients (ADC) of dry matter, lipid, ash and energy were not significantly different. However, protein digestibility in the 30 % MW group (80.4 %) was significantly lower (P ≤ 0.05) compared to the control and BS5 group (84.5 %). Furthermore, the ADC of protein was found to decrease linearly with increasing levels of insect meals, with MW showing a significant relationship (adjusted r2 = 0.77, p = 0.014). Overall, our study highlights the efficacy of 5 and 10 % BS and 15 % MW as ingredients in the feeds of Atlantic salmon. Other focal points included the undesirable amino acid derivatives and a reduction in protein digestibility associated with 30 % of MW in the diet of Atlantic salmon. Hence, future investigations should focus on the effects of feed processing conditions on the protein quality of mealworm before suggesting higher inclusion levels to the feed industry.

The effect of amplitude of heat flux on the adsorption of doxorubicin by MOF11 bio-carrier using molecular dynamics simulation

A common chemotherapy drug, doxorubicin's effectiveness is restricted by its quick excretion from the body and poor solubility. Because of their large surface area and adjustable pore size, bio MOF11 carriers demonstrated promise as drug delivery systems. Examining how external heat flux amplitude (EHFA) affects bio MOF11's ability to adsorb doxorubicin can reveal ways to improve drug loading and release, which will improve drug delivery. Moreover, by shortening the time needed for adsorption (Ads) and desorption, using EHFA in drug Ads processes can increase energy efficiency. Through comprehending the effect of EHFA on the Ads procedure, researchers can ascertain the ideal circumstances for optimizing drug loading while reducing energy usage. The current work examined the effect of EHFA amplitude on doxorubicin Ads via a bio MOF11 carrier using molecular dynamics (MD) modeling. According to MD data, EHFA was expected to have a significant effect on the atomistic evolution of the proposed drug-MOF11 system. The system's interaction energy (IE) and diffusion coefficient rose from −937.27 kcal/mol and 61.40 nm2/ns to −984.08 kcal/mol and 75.16 nm2/ns when EHFA changed from 0.01 to 0.05 W/m2. Increasing EHFA to 0.05 W/m2 resulted in a mean square displacement (MSD) parameter of 69.16 Å2. Therefore, based on the numerical results from this study, it can be said that the doxorubicin drug-MOF11 system changed and atomically evolved when the applied EHFA changes in magnitude.

Energy efficiency of hydrogen production during dark fermentation

It is widely known that most of the world's energy is produced from non-renewable energy sources such as crude oil and coal. Hydrogen is an ideal fuel candidate with a high energy content and clean combustion product. Biohydrogen is an environmentally friendly, renewable biofuel with high energy density, making it a viable alternative to fossil fuels in the future. At the same time, despite the large number of articles on the intensification of both dark fermentation and anaerobic bioconversion in general, the operating costs of the proposed intensification methods are not well covered in the literature. The goal of the work was to estimate the conversion coefficient of thermal and electrical energy spent on the functioning of the process of dark fermentation of various organic wastes into the energy of produced hydrogen. A block diagram of the energy flows of the dark fermentation system and the structure of the energy consumption of the system were developed. The obtained literature and experimental data suggest that the conversion coefficient of energy into biohydrogen in the process of dark fermentation is less than 1, so to obtain 1 kWh of hydrogen it is necessary to expend more than 1 kWh of energy. At the same time, the use of a vortex layer apparatus for dark fermentation of the food waste model made it possible to increase the energy output of the process by more than 7 times, thereby bringing the values of the conversion coefficients of thermal and electrical energy closer to 1. Despite the fact that the energy efficiency of most known methods for producing hydrogen is higher than the energy efficiency of dark fermentation, it is worth noting that the raw material for producing hydrogen in the dark fermentation process is organic waste, and not high-energy fuel (natural gas, methane, coal) or water in the case of electrolysis. In addition, the use of a vortex layer apparatus for pre-treatment of the dark fermentation substrate made it possible to achieve electricity conversion coefficient values 40% higher than with water electrolysis.

Scattering of e∓ in beryllium isonuclear series: cross sections and transport characteristics

The elastic scattering of electrons and positrons by beryllium atoms and its isonuclear ion states is described in this paper in terms of differential and various angle integrated cross sections. For this element, the critical minima in the elastic differential cross sections and the optimum spin polarization sites are found. These calculations are performed using the Dirac partial wave analysis (DPWA) and a projectile-target modified complex optical model potential. Further, the Monte Carlo method is used to calculate the transport characteristics of electrons in a mixture of inert gas (He, Ar) and beryllium vapor for electric field values E/N = 1-100 Td, taking into account inelastic collisions. We studied the effect of metal vapor concentration on drift velocity, average electron energy, diffusion and mobility coefficients. Finally, we investigated the effect of beryllium vapor on the electron energy distribution function in the inert gas. On comparing present work with existing theoretical calculation, a reasonable agreement is observed.

Multifeature Fusion Method with Metaheuristic Optimization for Automated Voice Pathology Detection

Voice pathologies occur due to various factors, such as malfunction of the vocal cords. Computerized acoustic examination-based vocal pathology detection is crucial for early diagnosis, efficient follow-up, and improving problematic speech. Different acoustic measurements provide it. Executing this process requires expert monitoring and is not preferred by patients because it is time-consuming and costly. This paper is aimed at detecting metaheuristic-based automatic voice pathology. First, feature maps of ten common diseases, including cordectomy, dysphonia, front lateral partial resection, contact pachyderma, laryngitis, lukoplakia, pure breath, recurrent laryngeal paralysis, vocal fold polyp, and vox senilis, were obtained from the Zero-Crossing Rate (ZCR), Root-Mean-Square Energy (RMSE), and Mel-frequency Cepstral Coefficients (MFCCs) using a thousand voice signals from the Saarbruecken Voice Database (SVD) dataset. Hybridizations of different features obtained from the voices of the same diseases using these three methods were used to increase the model's performance. The Grey Wolf Optimizer (MELGWO) algorithm based on local search, evolutionary operator, and concatenated feature maps derived from various approaches was employed to minimize the number of features, implement the models faster, and produce the best result. The fitness values of the metaheuristic algorithms were then determined using supervised machine learning techniques such as Support Vector Machine (SVM) and K-nearest neighbors (KNN). The F1 score, sensitivity, specificity, accuracy, and other assessment criteria were compared with the experimental data. The best accuracy result was achieved with 99.50% from the SVM classifier using the feature maps optimized by the improved MELGWO algorithms.

Apparent Digestibility Coefficients of Nutrients and Energy from Animal-Origin Proteins for Macrobrachium rosenbergii Juveniles

Apparent Digestibility Coefficients of Nutrients and Energy from Animal-Origin Proteins for Macrobrachium rosenbergii Juveniles

Establishing patterns of change in the coefficients of reflection, transmission, and dissipation of wave energy depending on parameters of a permeable vertical wall

The object of research is permeable vertical walls (breakwaters) with different degrees of permeability. This paper reports the results of experimental research into the interaction of gravity waves with models of permeable vertical walls (breakwaters), which were formed from cylindrical piles of circular cross-section. With the help of visual and instrumental studies, the features of interaction of surface gravity waves with permeable vertical walls of different permeability have been identified. The degree of wave transformation by these walls was also determined in the form of reflection, transmission, and dissipation coefficients of wave energy. It was established that with a decrease in the permeability of the vertical wall and an increase in the steepness of the initial wave and a decrease in its period, the height of the reflected wave increased. The pattern of the transmitted wave height had the opposite trend. It was determined that the wave reflection coefficient increased with a decrease in the permeability of the vertical wall and the steepness of the initial wave. The wave transmission coefficient had the opposite trend, namely, it increased with increasing wall permeability and with decreasing steepness of the initial wave. The gravity wave energy dissipation coefficient decreased with increasing vertical wall permeability, but for waves with a significant steepness hi/λ&gt;0.038, a decrease in the wave energy dissipation coefficient was observed for walls with low permeability and the appearance of extreme values of this coefficient. Thus, features in the interaction of surface gravity waves with permeable vertical walls (breakwaters) of different permeability have been researched and the degree of wave transformation by these walls has been determined, which could make it possible to effectively design and operate permeable vertical walls as coastal protection structures

Mode selection and combination rules of energy-based multimodal pushover method for simply supported beam bridges

The energy-based method (EBM) has been improved as Energy-based Multimodal Pushover Method (EMPM), and is introduced and verified to be effective and convenient for evaluate the seismic performance of the simply supported beam bridges. This paper mainly focuses on the research of vibration mode selection and combination rules of EMPM. Firstly, the longitudinal vibration modes of simply supported beam bridge are categorized into five cases based on mode shapes, and the case definition is emphasized. Then, corresponding to each case, the Pushover loading force are established, and the modal energy, modal displacement, and modal energy capability curve are proposed. After that, the energy-based demand curve and the corresponding energy coefficient for each case is recommended. Finally, only the mode with maximum mode participation factor (MPF) of each case is suggested to take part in the calculation of the seismic response with the proposed mode participation factor combination rule. Case studies of a practice bridge under Chi-Chi and El Centro earthquake waves are used to illustrate the effectiveness and accuracy of the proposed mode selection and combination rules. The study found that the EMPM with the proposed rules could effectively and rapidly assessing the seismic performance of the simply supported beam bridge, resulting in a 70 % decrease in time consumption compared with the Nonlinear Time History Analysis Method (NTHAM). Compared with the CQC and SRSS combination results, the proposed Mode Participation Factor (MPF) combination rule reduced the maximum relative deviation from 39.4 % to 21.09 % between EMPM and NTHAM for peak displacement. Further research showed that the proposed mode selection approach only uses modes with the highest MPF in each case, decreased the number of modes involved more than 50 % and the result accuracy remained almost identical.

Simulation of the Effect of Dy3+ Dopant on the Mass Energy Absorption Coefficient and Relative Energy Response of TLD Made from Lithium Magnesium Borate Using MCNP

Thermoluminescence dosimeter (TLD) is widely used as a personal and medical dosimeter. Several TLD materials show the characteristics of mass energy absorption coefficient and energy response relative to ICRU (International Commission on Radiation Units and Measurements) issue material as an equivalent material for human body soft tissue. This research aims to analyze the effect of Dy3+ dopant on the mass-energy absorption coefficient and relative energy response of Lithium Magnesium Borate (LMB) materials. The simulation was carried out using Monte Carlo N-Particle (MCNP) software. Calculations based on simulation and theoretical results will be compared statistically using paired t-tests. The study showed that adding a Dy3+ dopant to TLD material made of Lithium Magnesium Borate (LMB) only affected the mass-energy absorption coefficient and relative energy response for low radiation energy. Adding Dy3+ dopant increased the mass energy absorption coefficient and relative energy response in a reasonably small value. Based on these results, LMBDy3+ produces a better mass-energy absorption coefficient value for TLD materials. The results of the statistical tests show a significant difference in the mass energy absorption coefficient value. At the same time, there is no significant difference between the simulation results and theoretical calculations for the relative energy response.

Experimental Fitting of Efficiency Hill Chart for Kaplan Hydraulic Turbine

The development of hydroelectric technology and much of the “knowledge” on hydraulic phenomena derive from scale modeling and “bench” tests to improve machinery efficiency. The result of these experimental tests is mapping the so-called “hill chart”, representing the “DNA” of a turbine model. Identifying the efficiency values as a function of the specific parameters of the flow and energy coefficient (which both identify the operating point) allows us to represent the complete behavior of a turbine in hydraulic similarity with the original model developed in the laboratory. The present work carries out a “reverse engineering” operation that leads to the definition of “an innovative research model” that is relatively simple to use in every field. Thus, from the experimental survey of the degree of efficiency of several prototypes of machines deriving from the same starting model, the hill chart of the hydraulic profile used is reconstructed. The “mapping” of all the characteristic quantities of the machine, together with the physical parameters of the regulating organs of a four-blade Kaplan turbine model, also made it possible to complete the process, allowing to identify not only the iso-efficiency regions but also the curves relating to the trend of the angle of the impeller blades, the specific opening of the distributor, and the identification of critical areas of cavitation. The development of the hill chart was made possible by investigating the behavior of 33 actual prototypes and 46 characteristic curves derived from the same reference model based on practical experiments for finding the optimal blade distributor “setup curve”. To complete this, theoretical characteristic curves of “not physically realized” prototypes were also mapped, allowing us to complete the regions comprising the diagram. The study of the unified hill charts found in previous documentation of the most famous manufacturers was of great help. Finally, the validation of the “proposed procedure” was obtained through the experimental survey of the actual efficiency of the new prototype based on the theoretical values defined in the design phase on the chart obtained with the method described.

Investigating the impact of nuclear surface energy coefficients on one-proton radioactivity

Investigating the impact of nuclear surface energy coefficients on one-proton radioactivity

The combined effects of electric field and embedded dielectric matrix on the electronic and optical properties in Ge/SiGe core/shell quantum dots and its SiGe/Ge inverted structure

In this study, the binding energy (BE) and photoionization cross-section (PICS) coefficients in a Ge/Si0.15Ge 0.85 core/shell quantum dots (CSQDs) and in its inverted structure Si0.15Ge0.85 / Ge (ICSQDs) are studied. The influence of the hydrogenic impurity and capped matrix are taken into account. The electronic states and their related eigenfunctions are computed by solving the three-dimensional Schrödinger equation under the framework of the effective mass approximation (E.M.A) using the variational dimensional. The influence of the core radius and electric field strength on the BE and PICS are investigated. The numerical results reveal that the optoelectronic properties are considerably affected by the electric field strength (EF), immersed oxide matrix (OM) and geometric parameter. The obtained results prove that the PICS magnitude increases as the core radius increases and its resonant peak moves towards the lower energies for Ge/Si0.15Ge0.85 CSQDs structure, and increases as the core radius decreases and its resonant peak experiences a blue shift with increasing core radius for Si0.15Ge 0.85/ Ge ICSQDs. Moreover, with the effects of the surrounding oxide matrix and electric field strength, the PICS magnitude is improved and their resonant peak suffers a redshift.