Microwave Output Research Articles

EFFECTS OF MICROWAVE ROASTING TIME ON PHYSICO-CHEMICAL PROPERTIES AND SENSORY EVALUATION OF GERMINATED RED BROWN RICE MILK

The study was aimed to investigate the effects of different microwave heating times (1, 2, and 3 min at output microwave of 800 W) in comparison with the traditional heating (3 min, 110oC) on some physico-chemical properties and sensory evaluation. The consumer survey for the final product use was also conducted to determine whether there is a significant difference in general liking of the product with gender. The results indicated that the product with the shorter microwave heating time contained higher protein and reducing sugar compared to traditional heating. The microwave heating time significantly affected the viscosity of milk, whereas insignificantly influenced color, pH, and TSS values of milk. Among samples, microwave roasted at 3 min provided the comparable total acceptance score in sensory evaluation of the traditional heating. The milk contains protein (0.18g/100ml), total lipid (0.87g/100ml), and carbohydrate (7.56g/100ml). No significant association between gender and opinion was found expressing the liking of the product in which there were 61.35% females and 45.58% males liking the product. This study revealed that microwave heating could be used for roasting step to replace the traditional roasting in terms of product quality and nutrient retention. The study also provided a basic formula of the main components of the rice milk and demonstrated that the using the germinated red-brown rice to produce the rice milk could provide the product, ensuring all main compositions of rice such as protein, lipid, and carbohydrate.

Preliminary research of a V-band coaxial relativistic transit-time oscillator with traveling wave output structure

A V-band coaxial relativistic transit time oscillator is presented. Different from the traditional transit time oscillator, in order to improve the power handling capacity, we replace the traditional standing wave extractor with a traveling wave output structure. The operation characteristic of modulation cavity is also different from traditional transit time oscillators. The electron load conductance of modulation cavity is designed to be positive to reduce the maximum surface electric field. The device is investigated by particle-in-cell (PIC) simulation and preliminary experiment. In PIC simulation, an output microwave of 689 MW at 60.16 GHz is obtained with a diode voltage of 400 kV and beam current of 5.0 kA. The saturation time is 22 ns and efficiency is 34.5%. In experiment, the radiation pattern of the system is measured, and output power is calculated. A 135 MW V-band microwave at 60.20 GHz is obtained with a diode voltage of 405 kV and beam current of 5.1 kA.

Simulations and Experiments of the Soil Temperature Distribution after 2.45-GHz Short-Time Term Microwave Treatment

Microwave treatment is a green and pollution-free soil disinfection method. The application of microwaves to disinfect soil before cultivation is highly important to increase crop yields and protect the ecological environment. The electromagnetic field is an important parameter influencing the soil temperature field in the process of microwave soil treatment, and the change in soil temperature directly affects soil disinfection. Therefore, this article carried out research on the heating pattern in North China loess due to microwave treatment. First, COMSOL software was employed to simulate the microwave soil treatment process to analyze microwave penetration into soil. Second, with the application of microwaves at the designed frequency produced with a 2.45-GHz tunable microwave generating microdevice, soil with water contents of 0%, 10%, 20%, and 30% was treated for 10~60 s (at 10-s time intervals), and experiments on the influence of the microwave output power, treatment time, and soil moisture content on the soil temperature were performed via the controlled variable method. The simulation results indicate that with increasing soil moisture content, the microwave frequency inside the soil model increases, and the electric field intensity value decreases in the model at the same depth. After microwaves traverse through the 20-cm soil model, the incident field strength is three orders of magnitude lower than the outgoing field strength. The results of the microwave soil treatment experiment reveal that: (1) Compared to microwave output power levels of 1.8 and 1.6 kW, a level of 2 kW is more suitable for microwave soil disinfection. (2) After treatment, the highest temperature occurs on the soil surface, not within the soil. (3) The location of the highest soil internal temperature after microwave treatment increasingly approaches the soil surface with increasing soil moisture content, and the microwave output power does not affect the location of the highest soil internal temperature. Combining the electromagnetic field simulation and microwave soil treatment experiment results, it was found that the higher the field strength is, the higher the temperature value, and the highest soil internal temperature after microwave treatment often occurs at the first electromagnetic wave peak.

Drying kinetics and upgrading characteristics analysis of Zhaotong lignite with microwave deep drying

ABSTRACT Dewatering is considered as extremely significant and primary step to enhance the quality of lignite. A great number of research focus on conventional fluidized-bed drying technology or dynamics. In this paper, the microwave deep drying kinetics of Zhaotong lignite under different power levels and with different sample thicknesses were investigated. The drying kinetics of microwave deep drying was fitted by 13 different drying models given in the literature. Experimental results indicated that the microwave deep drying process exists three segments: increasing-rate, falling-rate and brief constant-rate segment. The drying time decreased and drying rate increased with microwave output power level increase, while the microwave penetration depth in lignite was affected by sample thickness, hence there is an irregular relationship between lignite sample thickness and microwave drying time or drying rate. Based on non-linear regression analysis, the Page model was considered adequate to describe the microwave deep drying behavior of Zhaotong lignite under various conditions, and the model could be used for residual moisture water content prediction at any time during the microwave deep drying process. Effective diffusion coefficient increased along with microwave output power level increase. The activation energy of the moisture emission from the lignite under different power levels was estimated at 10.2202 W/g using modified Arrhenius equation. The pore structure damage was observed in the lignite samples after microwave deep drying by SEM analysis. The surface of upgraded lignite had visible cracks, defects and small fragments compared with the samples by conventional drying.

A novel dual-band nested transit time oscillator

A novel dual-band nested transit time oscillator (TTO) is proposed in this paper, which consists of an outer X-band coaxial TTO and an inner Ka-band coaxial TTO. It is capable of generating dual-band microwaves simultaneously with three distinctive features. First, the emission processes of inner and outer annular electron beams are independent. Second, the inner and outer high frequency structures are spatially isolated. Third, the inner and outer annular electron beams share the guiding magnetic field. Particle-in-cell simulation is performed where a voltage of 450 kV and a guiding magnetic field of 0.6 T are used. Simulation results demonstrate that microwave output with a frequency of 8.4 GHz and a power of 1.72 GW is obtained for the X-band, corresponding to a conversion efficiency of 42% and a microwave saturation time of 30 ns. Meanwhile, microwave output with a frequency of 31.3 GHz and a power of 1.18 GW is achieved for the Ka-band, corresponding to a conversion efficiency of 40% and a microwave saturation time of 15 ns.

A novel Ka-band coaxial transit time oscillator with internal extraction

In this paper, a Ka-band coaxial transit time oscillator (TTO) with internal extraction is proposed. Particle-in-cell simulation of this oscillator is performed to obtain results as follows: under the conditions of a diode voltage of 459 kV, current of 3.9 kA, and guiding magnetic field of 0.5T, microwaves with an output power of 0.75 GW and a frequency of 31.4GHz can be achieved with an efficiency of 42% and a saturation time of nearly 25ns. Moreover, the asymmetric mode competition is suppressed in the preliminary experiments. The study of a Ka-band TTO aims to extend the working frequency of high power microwave sources to a higher level. Such a device has three merits. First, it implements high power and high efficiency. Second, the internal extraction of the microwave output decreases the over-mode ratio in the microwave extraction region. Third, the over-mode ratio of the internal extraction is smaller compared with the external extraction, which can effectively suppress asymmetric mode competition.

Phase and Amplitude Control Integrated Circuit in 0.18 μm SiGe BiCMOS for Sub-6 GHz Phased Array Applications

This paper presents simulation results of the C-band transmit/receive (Tx/Rx) phased-arrays integrated circuit (IC) for sub-6 GHz communication links. It is based on 0.18 μm SiGe BiCMOS technology. Phase and amplitude control IC consists of one Tx/Rx channel. Digitally controlled phase shifter allows adjusting relative phase of the output microwave signal in the range from 0 to 360 degrees with 5.625 degree step (6-bit resolution). Digitally controlled active attenuator provides the transfer ratio adjusting in the range from 0 to –31 dB with 1 dB step (5 bit resolution). Amplitude and phase correction system based on integrated temperature sensor, auxiliary 4-bit phase shifter, 4-bit attenuator and digital control unit is implemented. Correction in –60—85 °C temperature range with 5-bit resolu-tion is provided. The root mean square (rms) phase adjustment error does not exceed 1.6 degree. The rms attenuation error does not exceed 0.37 dB. The noise figure in Rx mode is below 6.5 dB. The output power in Tx mode is above 6 dBm at P1dB. The power consumption is 375 mW and 525 mW in Rx and Tx modes respectively.

Selective Leaching Trace Elements from Bauxite Residue (Red Mud) without and with Adding Solid NH4Cl Using Microwave Heating

Bauxite residue (red mud), which is an industrial byproduct, contains valuable trace elements. Solid NH4Cl was used as a chlorinating agent during the microwave heating of red mud to convert trace elements into soluble metal chloride. Red mud was heated using microwave ovens under various conditions (i.e., with the addition of solid NH4Cl and with a range of microwave output powers and microwave heating times). Leaching tests were then conducted using deionized (DI) water on the microwave-heated red mud to leach trace elements from red mud. V, Cr, and As were selectively leached from the microwave heated red mud slurry (30% water content), whereas Mn, Cu, Co, Ni, Zn, and Pb were selectively leached from the microwave-heated red mud with the addition of solid NH4Cl. The oxides of V, Cr, and As in red mud could be transformed into metal chlorides by chlorination, which are insoluble in water, or could be easily volatilized when red mud was microwave-heated in the presence of solid NH4Cl. On the other hand, the oxides of Mn, Cu, Co, Zn, Ni, and Pb in red mud could be heated rapidly by microwave irradiating, resulting in metal chlorides in the presence of solid NH4Cl. Those metal chlorides are relatively soluble in water, leading to higher leaching efficiency for microwave-heated red mud with the addition of solid NH4Cl. Experimental results suggest that trace elements from red mud can be selectively leached by microwave heating of red mud without or with the addition of solid NH4Cl.

Microwave drying effect on drying characteristic and energy consumption of Ficus carica Linn leaves

AbstractFicus carica Linn leaves having significant pharmacological properties such as antioxidant, antifungal, antidiabetic, antibacterial, anti‐inflammatory, and anti‐pyretic are available just in season. The effective utilization of nutritional values of leaves with enhanced shelf life has gained attention. Drying is usually the preferred technique to eliminate microbial attacks and increase shelf life of seasonal food products. Therefore, in the present study, the effect of microwave drying conditions on effective moisture diffusivity, activation energy, specific energy consumption (SEC), and energy efficiency were investigated at various microwave output power levels and sample amounts. The seven mathematical models were applied to describe the microwave drying kinetics of leaves and Page model was found as the best model. The maximum effective moisture diffusivity and drying rate constant values were determined as 9.84 × 10−11 m2/s and 1.15 1/min, respectively, at microwave output power level of 900 W and sample amount of 20 g. The activation energy values were estimated using the modified Arrhenius equation associated with effective moisture diffusivity (Ea = 11.41 W/g) and drying rate constant (Ea = 8.28 W/g). Additionally, the minimum SEC and maximum energy efficiency values (%) were found as 5.60 MJ/kg water and 40.31, respectively, at microwave output power level of 360 W and sample amount of 100 g. The results obtained from the present study seemed potentially useful to explore the applicability of microwave drying on Ficus carica Linn leaves to expand the availability of leaves having numerous nutritional ingredients throughout the whole year and take the advantage of their benefits in various industries.Practical ApplicationsEven if the benefits of Ficus carica L. leaves have been well presented in various studies in the literature, no study was found particularly which investigated the microwave drying kinetics of these leaves. Apart from the mathematical modeling of the drying characteristic and energy aspects of the leaf samples, the present study also targets to expand the usage area of these leaves with high shelf life and enable people to reach the leaves easily throughout the whole year. Hence, this study has potential for the commercial usage of these leaves for their effective utilization in various industries; such as beverage, bakery, cosmetic, and so on. In that way, the valuable nutritional ingredients of these leaves have been turned in favor of human consumption.

Microwave drying of banana blossoms ( Musa acuminata ): Mathematical modeling and drying energetics

This research work explored the effect of microwave output power on drying characteristics, moisture diffusion, drying efficiency, and specific energy consumption. Banana blossoms was cut into 3 mm thickness and was dried as monolayers at five different power levels (160, 320, 480, 640, and 800 W). After drying, the powdered banana sample was analyzed for color attributes and functional characterization. Eight different mathematical models were investigated and the Page model was the best-fitted model for all samples with the maximum R2 values of 0.99359 (P-160 W), 0.99505 (P-320 W), 0.99344 (P-480 W), 0.99160 (P-640 W), and 0.99192 (P-800 W). The drying time was minimizing from 40 to 10 min as the microwave output powers increase from 160 to 800 W. The drying constant (k) is enhanced as microwave power increases. The effective diffusivity of banana blossoms varied from 4.428 × 10−7 to 1.171 × 10−7 m2/s and the activation energy was estimated as 7.96 W/g. Maximum energy consumption was found to be 7.74 MJ/kg water at 160 W, whereas minimum energy consumption was minimum (5.74 MJ/kg water) at a microwave power of 640 W. Energy efficiency increases with increasing microwave output power. Applied microwave output power was a critical aspect of all color parameters of the banana blossoms powder. Powdered banana blossoms dried at 640 W showed the highest lightness L* of 54.43 ± 0.46 with redness (a*) of 4.19 ± 0.03, and yellowness (b) of 10.71 ± 0.29. The highest water solubility index was 53.30 ± 0.59 % for the sample dried at 640 W and oil absorption capacity (g/g) and foaming capacity (ml) were varied from 1.76 ± 0.07 to 2.93 g/g and 1.67 ± 0.58 to 4.53 ± 0.57 ml. Practical applications Dehydrated banana blossoms could be an option to make convenience their utilization for different food products formulation, and food fortification. Hence, advanced drying techniques are needed in the current scenario. Microwave drying is one of the advanced drying techniques which helps to enhance the quality attribute of a dehydrated product in comparison to the conventional drying technique which produces a lower quality product and needs a longer processing time. Microwave drying of banana blossoms slices results in a considerable enhancement in the preservation quality. This research work will offer an alternative technique to make dehydrated banana blossoms with a considerably better quality of products. High-quality dehydrated banana blossoms can be practically implicated by the microwave drying technique with an optimum condition.

An inverted relativistic magnetron with virtual cathode based on bidirectional electron beams

An improved L-band inverted relativistic magnetron powered by a virtual cathode is presented. An extra emitter is introduced at the end of a slow-wave structure to reduce the desired π mode start-oscillation time, which is critical when short radiation pulses are required. Electrons produced by both upstream and downstream emitters are injected into the interacting space simultaneously, and the rapid increase in electron density in this region accelerates the establishment of a virtual cathode. Furthermore, the additional emitter provides more charged particles for beam–wave interaction, so that the amplitude of output power can be improved. The particle-in-cell simulation demonstrates that a power conversion efficiency of 76.5% could be obtained for a diode voltage of 500 kV and guiding magnetic field of 0.165 T. Compared with the same slow-wave structure powered by a single beam, the output microwave power is increased from 1.1 to 3.1 GW and the startup time is shortened from 53 to 29 ns.

Effect of a non-uniform annular electron beam on the microwave characteristics in a coaxial structure Ka-band RKA output cavity

The influence of electron beam uniformity on the microwave characteristics of coaxial structure Ka-band RKA output cavity is investigated with particle-in-cell simulations. The electron beam non-uniformity is simulated in four different electron emission models: (1) continuous non-emission area, (2) spaced emission, (3) enhanced emission and (4) current density variation emission. The simulation results with the first emission model shows that the output power of Ka-band RKA decreases as the non-emission area increases, while the continuous non-emission area has little effect on the frequency and pulse width of Ka-band microwave; The simulation results with the second emission model shows that the output power of Ka-band RKA is related to the distribution of Z-component of electric field and excitation electric field strength in the beam–wave interaction gap. The more uniform the distribution of Z-component of electric field is, the greater the output power is. The stronger the excitation electric field is, the greater the output power is; The simulation results with the third emission model shows that the intense current density in local area will cause the reduction of output power. The higher the current density of the enhanced emission area is, the smaller the output power is; The simulation results with the fourth emission model shows that the fluctuation of current density during the steady-state phase will cause the fluctuation of microwave frequency and output power. The fluctuation amplitude of frequency and output power are positively related to the fluctuation amplitude of the current density. The larger the fluctuation amplitude of current density is, the greater the fluctuation amplitude of frequency and output power are. The faster the current density changes, the greater the fluctuation amplitude of frequency and output power are.

Integration concept of an Electron Cyclotron System in DEMO

The pre-conceptual layout for an electron cyclotron system (ECS) in DEMO is described. The present DEMO ECS considers only equatorial ports for both plasma heating and neoclassical tearing mode (NTM) control. This differs from ITER, where four launchers in upper oblique ports are dedicated to NTM control and one equatorial EC port for heating and current drive (H&CD) purposes as basic configuration. Rather than upper oblique ports, DEMO has upper vertical ports to allow the vertical removal of the large breeding blanket segments. While ITER is using front steering antennas for NTM control, in DEMO the antennas are recessed behind the breeding blanket and called mid-steering antennas, referred to the radially recessed position to the breeding blanket.In the DEMO pre-conceptual design phase two variants are studied to integrate the ECS in equatorial ports. The first option integrates waveguide bundles at four vertical levels inside EC port plugs with antennas with fixed and movable mid-steering mirrors that are powered by gyrotrons, operating at minimum two different multiples of the fundamental resonance frequency of the microwave output window. Alternatively, the second option integrates fixed antenna launchers connected to frequency step-tunable gyrotrons. The first variant is described in this paper, introducing the design and functional requirements, presenting the equatorial port allocation, the port plug design including its maintenance concept, the basic port cell layout, the transmission line system with diamond windows from the tokamak up to the RF building and the gyrotron sources.The ECS design studies are supported by neutronic and tokamak integration studies, quasi-optical and plasma physics studies, which will be summarized. Physics and technological gaps will be discussed and an outlook to future work will be given.

Arbitrary Bias Point Control for Mach-Zehnder Modulator Using a Linear-Frequency Modulated Signal

A versatile arbitrary bias control technology for Mach-Zehnder modulators (MZMs) based on a linear-frequency modulated (LFM) signal is proposed. An LFM signal is applied to the direct current (DC) port of an MZM together with a DC voltage. The output microwave signal is measured and cross-correlated with the fundamental and frequency-doubled components of the LFM signal. Their ratio serves as the feedback signal to control the bias point. An experiment is carried out. Compared to the conventional single-frequency pilot-based bias control technique, the peak power of the LFM component in the output electrical signal decreases by more than 27 dB, and the error vector magnitude (EVM) of the output microwave signal evaluated by 1000 symbols is reduced from 13.632% to 5.929%.

Stochastic Analysis of Miniature Optoelectronic Oscillators Based on Whispering-Gallery Mode Electrooptical Modulators

We propose a theoretical analysis of the stochastic dynamics of miniature optoelectronic oscillators (OEOs) based on whispering-gallery mode resonators. The core element in this microwave photonic oscillator is a high-Q whispering-gallery mode resonator with quadratic nonlinearity, which simultaneously performs electrooptical modulation, frequency filtering and energy storage. This multi-task resonator allows the oscillator to feature improved size, weight and power metrics. In this article, we analyze how the various sources of optical and electrical noise in the oscillator are converted to output microwave signal fluctuations. We use an approach based on stochastic differential equations to characterize the dynamics of the microwave signal as a function of radiofrequency gain and laser pump power. This stochastic analysis also allows us to understand how key parameters of the resonator such as its intrinsic and extrinsic Q-factors influence the system's dynamics below and above threshold. The time-domain numerical simulations for miniature OEO stochastic dynamics provides an excellent agreement with the analytical predictions.

Efficient Relativistic Magnetron With a Split Cathode

An ${L}$ -band all cavity axial extraction (ACAE) relativistic magnetron (RM) with a split cathode is proposed. The proposed RM is driven by virtual cathode that formed by axial flow of electrons from two conical emitters at both sides of slow wave structure, which is different from other RM that powered by radial flow of electrons from a cathode inside the interaction region. This cathode structure is simple but practical to generate a squeeze state electron in an RM with almost all the output structure. To improve the output performance, the anode blocks are modified with additional sections at both ends. Particle-in-cell (PIC) simulation results illustrate that when this tube is applied with a diode voltage of 600 kV, an average output microwave power of 1.6 GW can be obtained. Comparing with ACAE-RM using a conventional transparent cathode, the power conversion efficiency is improved from 47% to 67%.

THE EFFECT OF MICROWAVE OUTPUT POWER ON DRYING KINETICS OF YOGHURT AND MATHEMATICAL MODELING OF DRYING CURVES

The objectives of this study were investigation the effects of microwave output powers on drying kinetics of yoghurt, selecting the best fitted thin-layer model to characterize the drying behavior of yoghurt and determination of the activation energy and effective diffusivity. In order to achieve these objectives, low-fat yoghurt was dried by using domestic microwave oven at different microwave output powers (100, 180 and 300 W). Average drying rates were determined as 1.49, 4.43 and 7.90 g H2O m-2 s-1 for microwave output powers of 100, 180 and 300 W, respectively. The effective moisture diffusivities were determined as 3.30 x 10-9, 6.62 x 10-9 and 1.15 x 10-8 m2 s-1 for 100, 180 and 300 W, respectively. The Ea of yoghurt was found as 3.62 W g-1. Midilli and others model was selected as best fitted model due to highest values of R2 and low values of χ2, RMSE and RSS.

Microwave drying behavior, energy consumption, and mathematical modeling of sewage sludge in a novel pilot-scale microwave drying system.

Microwave drying is attracting increasing attention due to its energy efficiency. A self-developed pilot-scale microwave dryer was used in this study to dry two different common types of sewage sludge, namely mechanically dewatered sewage sludge and composting dewatered sewage sludge, by using two heating modes: constant temperature and constant power modes. The microwave drying behavior, specific energy consumption, average drying rate, energy efficiency, and drying effect were explored considering the influences of microwave output power, initial mass, and heating mode. Results showed that the output power had the largest influence on specific energy consumption, energy efficiency, and drying efficiency, followed by the constant temperature and initial mass. The specific energy consumption of mechanically dewatered sewage sludge decreased by roughly 14%. By contrast, the average drying rate increased by approximately 6%, and the energy efficiency increased by approximately 20% for each 1kW increase in output power. Meanwhile, composting dewatered sewage sludge displayed drying effects at an output power of 3kW, and the temperature exceeded 80°C. The comparison of the two modes suggested that the constant temperature mode was better than the constant power mode considering product quality and operational safety. Compared with six thin-layer drying mathematical models, the Midilli-Kucuk model could provide a good fit for the constant temperature mode. The proposed microwave drying process exhibited effective performance in drying rate. This process also demonstrated considerable application potential for sewage sludge drying.

Operation analysis of the wideband high-power microwave sources based on the gyromagnetic nonlinear transmission lines.

The wideband High-Power Microwave (HPM) sources, which combine the advantages of narrowband and ultrawideband sources, have drawn much attention. As a kind of wideband source, the gyromagnetic nonlinear transmission lines (GNLTLs) can directly modulate the incident pulses into radio frequency pulses without relying on the interaction between e-beam and microwaves. Due to the special working mechanism of gyromagnetic precession, the center frequency of the GNLTL can also be adjusted in a certain range. Based on classical magnetism and a simplified model of the GNLTL, this paper semi-quantitatively and theoretically analyzed the generation mechanism of HPM and illustrated the influences of the variations of parameters on the output microwaves. Then, a simple simulation based on 1-dimensional transmission line modeling method was carried out to study the performance of the GNLTL quantitatively, with the coupling of 1D telegraphist equations and the 3D Landau-Lifshitz-Gilbert equation. Simulation results preliminarily verified the conclusions derived from the theoretical analysis, and some working characteristics of the GNLTL were also obtained. This paper may help to understand the special working mechanism of the GNLTL and provide certain guidance for related simulations and experiments.

Effect of the Erosion of Collector Surface on the Operation of a Pulse-Periodic Plasma Relativistic Microwave Generator

The pulse-periodic operation regime of a plasma relativistic microwave generator is considered. The reasons for the increase of average frequency of the output microwave radiation in a pulse train created in the same conditions of initial plasma generation are analyzed. The effect of solid body erosion that occurs due to the interaction of the relativistic electron beam with the collector surface on the output microwave radiation is studied. The analysis of experimental data is accompanied by numerical simulations by the electromagnetic PIC code KARAT. It is shown that increasing the amount of mater extracted from the surface of the collector during erosion leads not only to an increase of the plasma density, but it can also lead to qualitative changes of the parameters of the output radiation, which are caused by the change of microwave generation regime. In particular, the generation of an ion background that is inhomogeneous in the radial direction caused a change of conditions of plasma–beam interaction during the second half of the pulse and a change of the spectral density of radiation at the main frequency. Numerical simulations were used to demonstrate this for two different admixtures, iron and graphite.