Energy Input Research Articles

Surface-Activated Mechano-Catalysis for Ambient Conversion of Plastic Waste.

Improved recycling technologies can offer sustainable end-of-life options for plastic waste. While polyolefins can be converted into small hydrocarbons over acid catalysts at high temperatures, we demonstrate an alternative mechano-catalytic strategy at ambient conditions. The mechanism is fundamentally different from classical acidity-driven high-temperature approaches, exploiting mechanochemically generated radical intermediates. Surface activation of zirconia grinding spheres creates redox active surface sites directly at the point of mechanical energy input. This allows control over mechano-radical reactivity, while powder catalysts are not active. Optimized milling parameters enable the formation of 45% C1-10 hydrocarbons from polypropylene within 1 h at ambient temperature. While mechanochemical bond scission is undesired in plastic production, we show that it can also be exploited for chemical recycling.

A preference adjustable capacity configuration optimization method for hydrogen-containing integrated energy system considering dynamic energy efficiency improvement and load fast tracking

The new hydrogen-containing integrated energy system proposed in this paper has complementary coupling of multiple energy forms such as electricity, gas, cold, heat, and hydrogen. For the same type of load demand, equipment with different energy input forms can be dispatched for joint supply. However, different equipment differ in dynamic response speed and energy utilization efficiency, and the reasonable configuration of equipment capacity will directly affect the overall dynamic characteristics and energy efficiency level of the system. Therefore, this paper first proposes an evaluation index that can comprehensively characterize the dynamic energy efficiency and load tracking ability of energy equipment. In addition, a preference adjustable capacity configuration optimization method based on utopian point tracking is proposed with the two optimization objectives of this indicator and the system's equivalent annualized investment cost, and the solution complexity is reduced through segmented linearization of the objective. Simulations presented here show that the capacity configuration optimization method proposed in this paper has a positive effect on improving the dynamic energy efficiency and load tracking ability of the new hydrogen-containing integrated energy system, and can also meet the preference setting needs of different investment entities for capacity configuration optimization goals.

Generation of Large-Scale Plasma Jet with Excitation of Bipolar Nanosecond Pulse Voltage in Single-Spiral Electrode Configuration

In this study, a single-outer-spiral electrode with inductance of 20 μH is employed to couple the energy input of a bipolar nanosecond pulse for the purpose of generating a large-scale atmospheric pressure plasma jet. When the spiral electrode is wrapped around a plasma jet tube with a length of 35 cm, the electrical field can be optimized, resulting in a stable laminar flow field, and a plasma jet with a length and diameter larger than 14 cm and 1.2 cm can be generated. A comparative study of the bipolar and unipolar pulse excitation voltages is also conducted, showing that the maximum lengths of the plasma jet excited by a bipolar pulse voltage, positive pulse voltage, and negative are 14 cm, 10 cm, and 7 cm, respectively. The temporal and spatially resolved spectra of the plasma jets excited by both bipolar and unipolar pulses are investigated, respectively, and the main physiochemical processes of the active species and the plasma dynamics’ evolution are discussed.

Ballistic-aggregated Carbon Nanofoam in Target-side of Pulsed Laser Deposition for Energy Storage Applications.

In pulsed laser deposition, along the traditionally exploited deposition on the front-side of the plasma-plume, a coating forms on the surface of the target as well. For reproducibility, this residue is usually cleaned and discarded. Here we instead investigate the target-side coated materials and employ them as a binder-free supercapacitor electrode. The ballistic-aggregated, target-side nanofoam is compact and features a larger fraction of sp2-carbon, higher nitrogen content with higher graphitic-N and lower oxygen content with fewer COOH groups than that of diffusive-aggregated conventional nanofoams. They are highly hydrogenated graphite-like amorphous carbon and superhydrophilic. The resulting symmetric micro-supercapacitor delivers higher volumetric capacitance of 522 mF/cm3 at 100 mV/s and 104% retention after 10000 charge-discharge cycles over conventional nanofoam (215 mF/cm3 and 85% retention) with an areal capacitance of 134 μF/cm2 at 120 Hz and ultrafast frequency response. Utilizing the normally discarded target-side material can therefore enable high performing devices while reducing waste, cost and energy input per usable product. leading towards a greater sustainability on nanomaterials synthesis and deposition techniques.

Investigation of mechanical and wettability properties of commercial pure titanium by surface mechanical attrition treatment

The examination of mechanical and wettability properties of commercial pure titanium (CP-Ti) introduced a novel challenge. The microstructure of samples was analyzed by using OM and SEM micro-images. In this study, the hardness of the surface and cross section of samples was evaluated, and the effect of several surface mechanical attrition treatments (SMATed) on samples was examined. Also, the tensile test was done to compare the effect of SMAT duration on mechanical properties of samples. The contact angle method was then employed to investigate the impact of SAMT duration on the wettability trend. According to results, as the treatment time increases, twins become evident in the deeper layers of the samples. In contrast, the near-surface twins are shorter than those found in the deeper material, signifying the presence of finer grains. Moreover, the elevated hardness in SMATed samples can be attributed to several key factors, including cold work, a rise in defects and twins, and grain refinement. The surface hardness increases across the sample series (up to Ti6) due to the substantial energy input. Nevertheless, it is anticipated that further continuation of the process will result in a constant surface hardness. The increased strength observed in SMATed samples can be attributed to factors such as reduction in grain size and the formation of twins. The wettability results show that the treated surfaces exhibited a significant change in wettability compared to the untreated samples, with a 25% reduction in the contact angle. This is attributed to the surface modifications induced by the treatment process, which introduced more hydrophilic functional groups. The results also show that after 4 h of treatment, the contact angle increases, suggesting that the trend may plateau with additional treatment time.

Influence of pier height and ground motion parameters on seismic response and energy dissipation of isolated railway bridges

The overlap between high-speed railways and earthquake areas makes it necessary to implement isolation design for railway bridges. At present, the variation of seismic energy of railway bridges with structural and ground motion parameters is not clear. In this paper, the finite element models of railway bridges with different pier heights are established and verified by shaking table tests. Then, the nonlinear time history analysis of isolated and non-isolated models is carried out, and the differences in seismic response and energy dissipation between the two models under different parameters are compared. Finally, the isolation effect of hyperbolic friction pendulum bearing (HFPB) is evaluated by using the efficacy coefficient method. Results demonstrate that HFPB can not only reduce the seismic response of the girder and the pier, but also effectively reduce the seismic input energy, structural damping energy, and pier hysteretic energy. In addition, HFPB has a better seismic isolation effect when pier height is 3–15 m, site characteristic period is 0.25–0.45 s, and earthquake PGA is 0.2–0.5 g.

A Comparative Analysis of Land, Water and Energy Requirements for Hydroponic and Conventional Cultivation of Horticultural Crops

The increasing global population and limited availability of arable land have necessitated the development of efficient and sustainable agricultural practices. Hydroponic cultivation has emerged as a promising alternative to conventional soil-based farming, particularly for horticultural crops. This review paper presents a comprehensive comparative analysis of the land, water, and energy requirements for hydroponic and conventional cultivation methods. The study aims to evaluate the sustainability and resource efficiency of these two approaches in the context of horticultural crop production. A thorough literature review was conducted, focusing on peer-reviewed articles, research reports, and case studies that compared hydroponic and conventional cultivation in terms of their resource utilization. The analysis encompassed various horticultural crops, including leafy greens, fruiting vegetables, and herbs. Key parameters such as land use efficiency, water consumption, nutrient management, energy inputs, and yield were examined. The findings revealed that hydroponic systems exhibited significantly higher land use efficiency compared to conventional farming. Vertical stacking and intensive production in controlled environments allowed for greater crop yields per unit area. Furthermore, hydroponic cultivation demonstrated superior water use efficiency, with recirculating systems reducing water consumption by up to 90% compared to traditional irrigation methods. Precision nutrient management in hydroponics minimized nutrient waste and runoff, contributing to enhanced resource conservation. However, the energy requirements for hydroponic cultivation were found to be higher than those for conventional farming, primarily due to the need for artificial lighting, climate control, and pumping systems. Strategies for optimizing energy efficiency, such as the use of renewable energy sources and energy-efficient equipment, were explored.

Life cycle assessment of suberin and betulin production from birch bark

In this study, the environmental impact of suberin and betulin production from birch outer bark was evaluated using life-cycle assessment (LCA), and the ReCiPe 2016 Midpoint (H) method. The system boundary includes production of outer bark to betulin and suberin production, with bark residues utilized for energy production, including all inputs (materials and energy) and outputs. Three scenarios were used to examine using the allocation, extraction and hydrolysation of birch bark. In the baseline scenario (S1), the bark came from a biorefinery and processed in a separate unit, where the hydrolysed bark residue was incinerated to generate the heat; the integrated scenario (S2) and internal loop scenario (S3) considered production within a biorefinery but with different energy sources. The primary data were collected from laboratory experiments, and secondary data were taken from the literature and the ecoinvent 3.9.1 database. FU was 2.06 kg of polymer production that includes 1 kg of suberin and 1.06 kg of betulin production from the same process. The results showed that the global warming potential (GWP) for S1 was 15.5 kg CO2 eq. per FU, 16.22 kg CO2 eq./FU in S2 and 3.96 kg CO2 eq./FU in S3. According to our results, increasing the recycling rate of ethanol (50%, 90% and 98%) in the process and using wood-based energy from the biorefinery instead of Finnish mixed electricity resulted in a significant reduction in the most important environmental impact categories except land use.

Numerical simulation of thermal-flow-magnetic coupling dynamics during P-type monocrystalline silicon removal in electrical discharge machining

To investigate the mechanisms underlying material removal and crater formation on semiconductor silicon in electrical discharge machining (EDM), this study presents a comprehensive thermal-flow-magnetic coupling simulation model, taking into account the synergistic effects of temperature, fluid dynamics and electromagnetic fields. Utilizing the model, the removal dynamics of P-type monocrystalline silicon within a monopulse discharge interval were meticulously simulated. Subsequently, the crater formation mechanism, as well as variations in the temperature and velocity fields, were thoroughly examined. The simulation model’s validity is experimentally confirmed. Findings indicate that an augmentation in pulse duration and thermal energy input precipitates a progressive expansion of the heat-affected zone in silicon. Concurrently, the temperature field’s expanse and the melting-vaporization frontier extend accordingly. The material undergoes instantaneous vaporization upon exposure to the high-temperature heat source. The volumetric expansion of the vapor is substantial, engendering a thermal explosive force that has a significant impact on the molten material. Ejection of material is attributed to the interplay between thermal explosive forces and electromagnetic influences. Experimental observations show that the morphology and dimensions of the simulated crater closely match those of the experimental crater, affirming the model’s capability to elucidate the crater formation mechanism in EDM processes.

Effect of microwave and ultrasonic pre-treatments on anaerobic co-digestion of orange wastes and municipal sewage sludge: A case study

The application of orange wastes (OW) in anaerobic digestion process still constitutes a technological challenge. One of the possibilities to overcome this issue is application of pre-treatment strategy. In this study, the effect of microwave (MW) and ultrasonic (US) pre-treatments on OW and sewage sludge (SS) co-digestion was examined. Firstly, the selection of optimal pre-treatment conditions in terms of solubilisation and generation of inhibitors (phenol and limonene contents) was conducted. For MW, irradiation time of 10 min and specific energy input of 28 089 kJ/kgTS were chosen as optimal. For US pre-treatment, specific energy input of 8914 kJ/kgTS and time of 20 min were adopted. Then, the mesophilic anaerobic co-digestion in batch mode was performed. However, neither of the two proposed pre-treatments had a significant impact on methane production, as compared to the untreated sample.

An energetic approach to the statistical analysis and optimization of friction welding processes applied to an aluminum-steel-joint

The present publication deals with an energy-oriented approach to the statistical analysis of rotational friction welding processes. To illustrate the methodological approach, it is applied to investigate the effects of energy flow on material flow behavior and joint quality during friction welding of an AA6060 alloy with a low-alloy 16MnCr5 filler steel. The influences of the setting parameters on the energetic states are first analyzed by means of an initial screening. The evaluation using process simulation and statistical methods enables the generation of regressive response surfaces for the friction power, the friction time and the resulting induced friction energy. Based on these findings, a second experimental field is formed and evaluated, which considers the interaction between the energy input of the frictioning stage and the workpiece forging. This new approach results in the functional separation of the frictioning and forging stage, which eliminates the usual statistical interaction effects and thus facilitates analysis and optimization. The qualitative result variable required for the purpose of interpreting the results is the ultimate tensile strength of the friction-welded joint. Additionally determined hardness curves provide information about the properties of the thermally influenced zone and strength-relevant process sequences. The result is that, in addition to the amount of energy induced, the frictional power with which the former is induced also has a considerable influence on the joint strength, as it influences the material flow and the properties of the joining zone.

Study on Laser Transmission Welding Technology of TC4 Titanium Alloy and High-Borosilicate Glass.

As the demand for high-performance dissimilar material joining continues to increase in fields such as aerospace, biomedical engineering, and electronics, the welding technology of dissimilar materials has become a focus of research. However, due to the differences in material properties, particularly in the welding between metals and non-metals, numerous challenges arise. The formation and quality of the weld seam are strongly influenced by laser process parameters. In this study, successful welding of high-borosilicate glass to a TC4 titanium alloy, which was treated with high-temperature oxidation, was achieved using a millisecond pulsed laser. A series of process parameter comparison experiments were designed, and the laser welding behavior of the titanium alloy and glass under different process parameters was investigated using scanning electron microscopy (SEM) and a universal testing machine as the primary analysis and testing equipment. The results revealed that changes in process parameters significantly affect the energy input and accumulation during the welding process. The maximum joint strength of 60.67 N was obtained at a laser power of 180 W, a welding speed of 3 mm/s, a defocus distance of 0 mm, and a frequency of 10 Hz. Under the action of the laser, the two materials mixed and penetrated into the molten pool, thus achieving a connection. A phase, Ti5Si3, was detected at the fracture site, indicating that both mechanical bonding and chemical bonding reactions occurred between the high-borosilicate glass and the TC4 titanium alloy during the laser welding process.

Analysis of laser beam welding with superimposed 445 and 1070 nm wavelength lasers on copper by in situ synchrotron diagnostics

In laser welding, precision and reproducibility are fundamentally dependent on temporal and spatial processes of energy input. Induced by the dynamics of the melt pool, pressure equilibria in the vapor capillary, and solidification behavior, different weld seam qualities are achieved. To obtain the lowest possible defect frequency, new tailored joining strategies need to be investigated using multibeam and multiwavelength approaches. To improve the quality by influencing the process dynamics, a dual-beam approach is investigated that superimposes a stationary laser beam with a wavelength of 445 nm with a spatially modulated laser beam with a wavelength of 1070 nm. The aim is to utilize ∼10 times higher absorption of a 445 nm diode laser on copper with the high focusability of a 1070 nm fiber laser. In this context, the influence of the relative positions of the two beams to each other on the weld seam quality is investigated, while one of the beams moves either in front, behind, or coaxial to the other beam following the path of a line weld. The main objective is to observe how the laser beams influence each other and how the capillary depth and porosity vary for different parameters. To visualize the process dynamics, the welding experiments on copper are performed at the Deutsches Elektronen-Synchrotron DESY by means of in situ phase contrast videography. Quality-determining weld properties like the distribution of pores or process fluctuations are then extracted automatically from the image sequences by means of a trained neuronal network.

Reductive Inner-Sphere Electrosynthesis of Ammonia via a Nonelectrocatalytic Outer-Sphere Redox.

Electrochemistry of outer-sphere redox molecules involves an essentially intact primary coordination sphere with minimal secondary sphere adjustments, resulting in very fast electron transfer events even without a noble metal-based electrocatalyst. Departing from conventional electrocatalytic paradigms, we incorporate these minimal reaction coordinate adjustments of outer-sphere species to stimulate the electrocatalysis of energetically challenging inner-sphere substrates. Through this approach, we are able to show an intricate 8e- and 9H+ transfer inner-sphere reductive electrocatalysis at almost half the energy input of a conventional inner-sphere electron donor. This methodology of employing outer-sphere redox species has the potential to notably improve the cost and energy benefits in electrochemical transformations involving fundamental substrates such as water, CO2, N2, and many more.

Thermodynamic Study of 1,4-Bis(3-methylimidazolium-1-yl)butane Bis(trifluoromethylsulfonyl)imide ([C4(MIm)2][NTf2]2) from 6 to 350 K.

The molar heat capacity of 1,4-bis(3-methylimidazolium-1-yl)butane bis(trifluoromethylsulfonyl)imide dicationic ionic compound ([C4(MIm)2][NTf2]2) has been studied over the temperature range from 6 to 350 K by adiabatic calorimetry. In the above temperature interval, this compound has been found to form crystal, liquid, and supercooled liquid. For [C4(MIm)2][NTf2]2, the temperature of fusion T°fus = (337.88 ± 0.01) K has been determined by the fractional melting experiments, the enthalpy of fusion ΔfusH° = (52.79 ± 0.28) kJ mol-1 has been measured using the calorimetric method of continuous energy input, and the entropy of fusion ΔfusS° = (156.2 ± 1.7) J K-1 mol-1 has also been evaluated. The standard thermodynamic functions of the studied dicationic ionic compound, namely, the heat capacity Cp°(T), the enthalpy [H°(T) - H°(0)], the entropy S°(T) and the Gibbs free energy [G°(T) - H°(0)] have been calculated on the basis of the experimental data for the temperature range up to 350 K. The results have been discussed and compared with those available in the literature and in the NIST Ionic Liquids Database (ILThermo) for monocationic ionic compounds.

A discrete CMUT self-biasing circuit towards implanted devices application

Wireless power transfer is an essential feature of biomedical engineering. It reduces the need for energy storage devices in medical implants. To recharge a body implanted battery, a convenient way is to transmit ultrasounds through the skin to a connected ultrasonic transducer. Lead-less, System-on-Chip compatible (SoC) and wideband, Capacitive Micromachined Ultrasonic Transducers (CMUT) are competitive with piezoelectric based technologies. However, their need for a high bias voltage is an obstacle to their use in implanted medical devices (IMDs). The voltage source required must meet precise specifications, such as reliability and volume, which the research community intends to respect. To meet this challenge, this work proposes an electronic circuit that allows a CMUT device to self-bias from a very low initial energy input. After presenting the electronic architecture and its main features, simulation and experimental results validate the solution’s working principle and operating points. With an electronic circuit made up of discrete components, a bias voltage of 60 V is built up from an implanted battery voltage of 2.2 V and an incident pressure of 120 kPa in water.

Description Of Nutritional Status In Students Mts Al-Amin Pakis

Adolescents are an age group that is vulnerable to experiencing malnutrition or excess nutrition problems. Teenagers generally carry out higher physical activity compared to other ages, so they require more nutritional fulfillment. However, the incidence of overnutrition in adolescents can also occur due to poor eating habits so that the amount of energy input is greater than the energy expended. The purpose of this study was to describe the nutritional status of students. This type of research is quantitative with an analytical descriptive design on 85 students of MTs Al-Amin Pakis. Data on nutritional status were obtained by measuring the height using a microtoise and the respondent's weight using a mechanical scale. Nutritional status is classified based on the value of the BMI/age z-score table for children aged 5-18 years from the 2011 Indonesian Ministry of Health guidelines. The results of the data analysis obtained the nutritional status category of junior high school students who were involved as the majority of respondents who were in the normal nutritional status category, namely 77 people (90.58%). However, there were still 8 students (9.41%) who were obese.

Near-Inertial Response of a Salinity-Stratified Ocean

Abstract We study the near-inertial response of the salinity-stratified north Bay of Bengal to monsoonal wind forcing using 6 years of hourly observations from four moorings. The mean annual energy input from surface winds to near-inertial mixed layer currents is 10–20 kJ m−2, occurring mainly in distinct synoptic “events” from April–September. A total of fifteen events are analyzed: Seven when the ocean is capped by a thin layer of low-salinity river water (fresh) and eight when it is not (salty). The average near-inertial energy input from winds is 40% higher in the fresh cases than in the salty cases. During the fresh events, 1) mixed layer near-inertial motions decay about two times faster and 2) near-inertial kinetic energy below the mixed layer is reduced by at least a factor of three relative to the salty cases. The near-inertial horizontal wavelength was measured for one fresh and one salty event; the fresh was about three times shorter initially. A linear model of near-inertial wave propagation tuned to these data reproduces 2); the thin (10 m) mixed layers during the fresh events excite high modes, which propagate more slowly than the low modes excited by the thicker (40 m) mixed layers in the salty events. The model does not reproduce 1); the rapid decay of the mixed layer inertial motions in the fresh events is not explained by the linear wave propagation at the resolved scales; a different and currently unknown set of processes is likely responsible.

Study on no IMC Solid state bonding method for high-density 2.5D/3D integration

Abstract Chiplet integration is a new development direction for the continuation and even goes beyond Moore’s Law, and in order to achieve the high density, high reliability, high-speed Chiplet device, a new method of 2.5D/3D integration approach is needed to fulfill the needs to Chiplet heterogeneous devices. In this work, two dies were successfully bonded via low energy input with no IMC solid state bonding under 220°C and 5 MPa, which is much gentler than the other solid state bonding approaches. Each die had a matrix of 22500 Cu pillars with a diameter of 20 μm. This method was promising for the near future high-density 2.5D/3D integration.

Modeling of nonlinear self-excited forces: A study on flutter characteristics and mechanisms of post-flutter behaviors

The intrinsic physical relevance of higher-order self-excited force (SEF) components has received limited attention, and there is a dearth of formulas that adequately analyze the influence of SEF components on the post-flutter characteristics. Based on Taylor formulas and the principle of independence, semi-empirical polynomial SEF models are developed and validated. The energy input efficiency and role of each order SEF component are examined using the proposed models. By introducing the principle of energy equivalence and approximate average power, theoretical formulas designed to calculate the post-flutter characteristics are established. Finally, the applicability and robustness of the SEF models and theoretical formulas are discussed. Results show that the proposed models can obtain independent higher-order SEF components, which is conducive to the correct analysis of the SEF driving mechanisms. The theoretical formulas can accurately reconstruct the time-varying curves of the flutter characteristics, and the terms in the formulas can explicitly calculate and analyze the mechanism of each SEF model element. It is observed that the higher-order SEF components have a significant impact on the accurate reconstruction of SEFs while barely affecting the system energy. Moreover, the limit cycle oscillation generation mechanisms of the investigated two rectangular cylinders are different, but the variation of the flutter characteristics with time remain the same.