In this study, we evaluated the redox reaction of iron oxide, an iron-based oxygen carrier (OC) used in chemical looping hydrogen production (CLHP) processes, and identified optimal reaction conditions. Furthermore, we investigated the direct reduction of OC using biomass with the aim of establishing carbon-neutral hydrogen produc-tion technology. Pre-oxidation treatment of the iron-based oxygen carrier effectively improved its surface structure and redox reactivity. Although natural iron-containing mineral exhibited lower gas reduction reactivity compared to pure iron oxide reagent, it contains multiple heat-resistant components that suppress particle aggregation under high-temperature conditions, demonstrating excellent reactivity in steam oxidation. In direct reduction experiments using biomass, woody biomass was directly introduced into the OC bed of a fluidized-bed reactor, and the reduction reaction was confirmed to proceed. The biomass-to-OC feed ratio and the biomass torrefaction treatment significantly affected the OC reduction conversion rate. Furthermore, the accumulation of biomass char in the reactor affected the fluidization behavior of the bed particles, thereby affecting the progress of the reaction. When good fluidization was maintained, stable hydrogen gas production was possible through the steam oxidation of reduced OC. These findings demonstrate the effectiveness of biomass utilization in the CLHP process and demonstrate its potential as a high-purity hydrogen production technology.
This study aims to capture the geographical structure of infection risk and its temporal dynamics at a macroscopic scale, by establishing a risk assessment framework based on human mobility networks. First, we define the Potential Risk Index (PRI), which does not rely on observed infection data, and visualize structural risk in the early stages of an outbreak by estimating latent contact opportunities from daily mobility patterns. We then introduce the Temporal Risk Index (TRI), which incorporates observed infection data accumulated after the outbreak, and classify regional infection trends by applying a polynomial approximation to the risk increment, calculated as the difference between TRI and PRI. Validation using real COVID-19 data demonstrates that PRI is effective for identifying spatial risk in the initial phase of the outbreak, whereas TRI is effective for dynamic risk assessment in the later stages. Furthermore, by overlaying spatial information such as Shinkansen lines, connecting bridges, and airports onto the classification results, we show that mobility and transportation networks can be extracted as structural factors associated with increases in infection risk. This framework complements conventional epidemiological approaches and provides an integrative method for evaluating both the spatial structure and temporal evolution of infection risk. It is expected to be applicable to the design of hazard maps and real-time decision support for infectious disease control in the future.
In this study, not only the supercritical CO2 extraction process for caffeine removal from green coffee beans but also the subsequent drying process was examined, and the effects of various treatment conditions were evaluated based on sugar residue rate and sensory analysis. A pre-soaking water content of 40 wt% was identified as optimal, and high-er caffeine extraction yields were achieved under elevated temperature and pressure conditions. Lower CO2 flow rates tended to improve extraction efficiency per unit CO2 consumption, however, the lowest flow condition required sig-nificantly longer extraction times. The introduction of a water-saturation cell into the extraction line effectively pre-vented drying during the extraction process, resulting in a marked improvement in extraction yield. Additionally, controlled-humidity drying after extraction led to a sugar loss of up to approximately 50%, nevertheless, sensory evalu-ations yielded high scores compared to untreated beans, suggesting the importance of evaluating overall quality, includ-ing contributions from components other than sugars.
The spread of infectious diseases in the livestock industry results in severe economic losses and social disruption. This study focuses on the 2010 outbreak of foot-and-mouth disease (FMD) in Miyazaki Prefecture, Japan, and proposes a framework for quantitatively assessing farm-level susceptibility to infection through the construction of a Potential Infection Risk Index (lambda). This index integrates multiple factors, including spatial proximity between farms, herd size, and livestock species. Statistical analysis reveals that lambda values significantly differ between infected and uninfected farms, with the disparity widening as distance from the infection source decreases. These findings indicate that the spread of infection is strongly influenced by both geographic proximity and structural characteristics of farms. Furthermore, lambda enables objective and quantitative identification of high-risk farms, supporting practical responses such as the prioritized allocation of limited disease control resources and the flexible application of hygiene management standards. A case study simulating farm relocation demonstrates that lambda-based site selection effectively reduces infection risk, thereby validating the index as a practical and economically rational decision-support indicator. This approach also suggests the potential application of lambda in long-term farm siting and structural planning. Additionally, the study envisions a com-prehensive disease control support system centered on lambda and its adjusted form (lambda'), incorporating features such as risk visualization, hygiene-related corrections, tailored alerts and recommendations, and integration with administrative decision-making processes. Future work will focus on the development and implementation of such decision-support tools, with the ultimate goal of enhancing disease control efforts and contributing to the sustainable development of the livestock industry.
The effect of particle size on the reactivity of the reformed magnesite by heating was experimentally investigated. The reactivity of no reforming magnesite was proportional to the particle size to the power of-0.78. The reactivity of the reformed magnesite can be estimated from the reforming rate and reactivity of no reforming magnesite. Even if the particle size is 1680 to 2000 mu m, the reformed magnesite can be used as the industrial desulfurizing agent when the reforming rate is 0.923 or higher.
In order to objectively determine the differential reactor conditions, which is one of the methods for estimating the initial reaction rate in reaction engineering, we proposed a method that applies the concept of explanatory variable selection criteria in multiple regression analysis, and examined its validity using previously published and new data. The two proposed evaluation indices apply Akaike's information criterion, which is one of the explanatory variable selection criteria in multiple regression analysis. The method was applied to reactions using a catalyst and reactions using an enzyme. As a result of the examination, it was suggested that the logarithm of the coefficient of determination divided by the degrees of freedom using Akaike's information criterion can be used as an objective index for determining the differential reactor conditions. Furthermore, the application of Akaike's information criterion was found to be a more versatile index, as it can be calculated even if you are not familiar with Excel functions or if you only have an electronic desk calculator that can perform simple regression analysis.
This study aims to elucidate characteristic thermo-fluid phenomena by measuring temperature fields in convection driven by temperature-induced density and surface tension gradients. Infrared thermography was employed for the visualization of the temperature fields, followed by spectral analysis to extract dominant thermal behaviors. Such convective phenomena are known to occur in the crystal growth processes of semiconductor materials, where they are recognized to have a significant impact on crystal quality. However, the underlying mechanisms of heat transport in buoyancy-driven and Marangoni (surface tension-driven) convection, the transition from laminar to turbulent flow, and the mutual interaction and transition between buoyancy and Marangoni convection remain insufficiently understood. To address these gaps, flow visualization experiments were conducted using a horizontal annular cylindrical vessel with an open upper boundary, filled with silicone oils of various viscosities. The temperature distribution at the gas-liquid interface was visualized using infrared thermography, and spectral analysis of the temperature fluctuations was performed to investigate the dynamic behavior and convective heat transfer mechanisms. The experimental results revealed that Marangoni convection can exhibit rotating steady waves, characterized by regularly rotating flow structures. These flows were observed to transition into non-rotating, unsteady wave patterns-specifically, pulsating or unstable oscillatory flows-as the fluid viscosity decreased, the imposed temperature difference increased, and the fluid layer thickness became greater. This indicates that the temperature field transitions from a stable, rotationally symmetric state to a more complex, three-dimensional structure. Furthermore, by organizing the relevant dimensionless numbers into a three-dimensional parameter space, the study successfully identified transitional regimes-such as those between buoyancy-driven and surface tension driven convection, as well as between laminar and turbulent flow.
In a previous report (Chemical Engineering Research and Design, 136, 251-261, 2018), a new dimensionless parameter for sublimation, apSP equivalent to kappa(-1)=(T-Solute(m)/T-0)(-2) (v(Solute)eSP(Solute)(2)/R)(-1), was derived. In the apSP value, T-Solute(m), v(Solute), eSP(Solute) and R are melting temperature, molar volume and entropy-based Solubility Parameter and gas constant, respectively. T-0 is the standard temperature (=298.2 K). In this work, this parameter was applied to evaporation process for pure substances. As a result, a new dimensionless number, apVP equivalent to(T-b/T-0)(-2) (v(Liquid)eSP(Liquid)(2)/R)(-1), was developed. In the apVP value, T-b, v(Liquid), eSP(Liquid) are boiling temperature, and molar liquid volume and eSP in liquid phase, respectively. From these results, it is possible to determine the Antoine constants (A, B, C) of an unknown substance by considering the saturated vapor pressure P-vp(0) at the standard temperature T-0, as well as the standard boiling point T-b at the standard pressure P-0 (=101.3 kPa) and the critical pressure P(C )at the critical temperature T-C.
The saturated vapor pressure of a pure substance under high pressure vapor-liquid equilibrium is a physical property that has been estimated using the Antoine equation consisting of three constants. Recently, more rigorous estimation equations consisting of five constants have been adopted. The end point of the saturated vapor pressure on the high temperature and pressure side is the critical point. In this study, the thermal pressure coefficient at the critical point was calculated using a saturated vapor pressure calculation equation consisting of five constants, and correlated with the critical molar volume vC, revealing that there was an exponentiation. As a result, a new theory for estimating critical molar volume from saturated vapor pressure estimation equations available from handbooks has been developed.
Painting liquid waste discharged from automobile factories contains high concentrations of phosphorus and nitrate; however it has not been considered to utilize because of containment of fluoride and heavy metals such as Ni and Zn. This study investigated the potential use of painting liquid waste as sources of nutrients for algal biomass production. Metals and fluoride were removed from Pw using Ca(OH)(2) and NaOH. The treated painting liquid waste (Pw9) was added to a Carefoot medium without addition of phosphorus to achieve a phosphorus concentration of 6.84 mg-P/L equivalent to that of the original Carefoot medium (C-P+Pw9 medium). In addition, the Pw9 was added to a Carefoot medium without addition of phosphorus and nitrogen to achieve a nitrogen concentration of 40.6 mg-N/L equivalent to that of the original Carefoot medium (C-PN+Pw9), while the phosphorus concentration was in excess (41.3 mg-P/L). The C-P+Pw9 and C-PN+Pw9 media were tested for algal cultivation. Because the algae grew in both media, the results confirmed that the Pw9 can be used as phosphorus and nitrogen sources for algal cultivation. However, the algal growth did not achieve that in the control experiment, indicating occurrence of growth inhibition. The inhibitory effect vanished by adding a chelating agent or phosphate (5 mg-P/L) to the C-P+Pw9 medium. In addition, no growth inhibition occurred by adding fluoride at the concentration in the C-P+Pw9 medium. These indicated that the causable substances in the Pw9 for algal growth inhibition were metals that inhibit utilization of phosphate by algae. The inhibitory effect by the Pw9 could be mitigated by adjusting the initial pH of the culture medium from 7 to 8.2. Vanishment of the algal growth inhibition in the C-P+Pw9 medium (6.84 mg-P/L) by addition of phosphoric acid of 5 mg-P/L implies that partial replacement of phosphorus source in algal medium with the Pw9 rather than its substitution by the Pw9 may be a method of effective utilization of the Pw9.
This study investigated feasibility of culturing Aurantiochytrium sp. strain 8W, a thraustochytrid producing polyun-saturated fatty acids, using udon noodle boiling wastewater (UBW) and waste seasoning liquid waste as examples of typical unused resources discharged from the food service industries. The UBW could be used for culturing the strain 8W after hydrolysis at pH 1, and it produced DHA at 19.8 mg/g. However, the low dissolved nitrogen (DN) content in the hydrolyzed udon noodle boiled wastewater (HUBW) might be a factor limiting the growth of strain 8W. On the other hand, the noodle sauce and miso soup with the higher DN content could be utilized as substrates too for the strain 8W; however, the DHA contents produced in the noodle sauce medium was similar to that in the HUBW. Be-cause of the high DN content, the miso soup was mixed with the HUBW and used as a culture medium for the strain 8W. The strain 8W successfully produced DHA and EPA at 150 mg/g and 5.1 mg/g of DHA and EPA, respectively, con-firming the usefulness of this combination. The DHA content in the strain 8W biomass produced by using the HUBW, the noodle sauce, and miso soup achieved the levels for enrichment of DHA in poultry products such as eggs and chicken meat, if it is used as an additive for poultry diet.
This study aims to structural analyses of the tar, one of the pyrolysis products, for the three different Mongolian brown coals (Baganuur, Shivee-Ovoo and Khuut). This pyrolysis coal tar (coal tar) were analysed by gas chromatography/mass spectrometer (GC/MS), at temperatures from 400 to 900 degrees C in a horizontal fixed-bed reactor. From the results, we are to reveal the differences among coal samples by applying chemometrics of principal component analysis (PCA). The coal tar mainly contained long-chain aliphatic compounds, such as n-alkanes, n-alkenes and aliphatic ketone, and polycyclic aromatic hydrocarbons (PAHs). The peak intensity of the aliphatics in each coal tar increased with the increase of temperatures up to around 600 degrees C, and decreased rapidly above 700 degrees C, while the concentration of total PAHs in tar exponentially increases exceeds 700 degrees C except for Baganuur coal. The total PAHs concentrations of coal tar of Shivee-Ovoo and Khuut at 900 degrees C were 57.1 and 34.7 mg/g, respectively. At 900 degrees C, the PAHs concentration of Baganuur coal tar had the lowest value of 8.85 mg/g among them. This is assumed to be because the O/C value was the lowest compared to the other two coal types, which made it difficult for the thermal decomposition to proceed. PCA analysis showed that there is a negative correlation between the aliphatic compound amounts and the PAHs concentrations at pyrolysis temperature above 800 degrees C, implying that aliphatic compounds are converted to PAHs by the pyrolysis. It also demonstrated differences in tar components from pyrolysis, suggesting that this may be a useful indicator for evaluating lignite quality.
By pressurized hot water treatment, total polyphenols, hydroxytyrosol and tyrosol were extracted from olive pomace, and the agricultural use of the extraction residue was examined. As a result of extracting components with a batch-type reactor with a volume of 500 mL, the total polyphenols, hydroxytyrosol and tyrosol were extracted under the condi-tion that the reaction temperature was 20280 degrees C, the reaction time was 30 min, and the amount of extraction of each component increased markedly when it exceeded 160 degrees C.The recovery rate of each component was almost 100% for total polyphenols, 84% for hydroxytyrosols and 63% for tyrosols. As a result of treatment with a batch-type reactor with a volume of 3.2 L, the extraction amount and recovery rate of each component increased from that of a reactor with a volume of 500 mL, and the tendency to produce unknown components was similar.The amount of extraction of each component is large, and the processing temperature of 240 degrees C was considered optimal as a condition to minimize the influence of unknown components. Komatsuna (Japanese Mustard Spinach, Scientific Name: Brassica rapa L. cv. Rakuten) was developed using the extraction residue from pressurized hot water treatment at the condition (reaction temperature of 240 degrees C and a reaction time of 30 min). In the condition that the mixing rate of the dry powder of the ex-traction residue is less than 1%, Komatsuna is grown as the chemical fertilizer zone.
This study evaluates the grinding performance of a cutter-type disk mill at different particle feed rates. A coupled DEM-CFD simulation incorporating a breakage model was used to investigate the effect of feed rate on the grinding performance of resin particles. The simulation results show that the particle residence time in the grinding section of the Type A blade tends to increase when the feed rate is high. This is because the design of the milling blade reduces the particle velocity and increases the filling ratio, which increases the load on the motor and may cause the mill to stop operation. On the other hand. Type B grinding blades tend to have a coarse particle size distribution as the feed rate increases due to the high particle velocity within the grinding section. However even with an increase in the feed rate. there is a high probability that the operation will be stable. This study shows that DEM-CFD simulations are effective in evaluating the grinding performance of cutter-type disk mills under different operating conditions, providing import-ant insights for mill design and operational optimization.
Chemical plants are rapidly shining their operations towards high-efficiency and decarbonization. this transition has led to an increase in the number of key performance indicators (KPIs) for operators, and the allowable time for the identification of process abnormalities has been reduced. Consequently, a method for reducing the workload of operators and for detecting the cause of process abnormalities in a prompt manner is required. the study proposes a methodology for designing operator-level KPIs that are aligned with the goals of high-efficiency and decarbonization in production. the proposed approach involves the development of a novel defenition of Total KPIs, the updating of the calculation formula of previously reported KPIs for plant management, the establishment of Partial KPIs that divide Total KPIs into facility/equipment, utilities, raw materials, or products, and the identification of Disturbance KPIs that pinpoint the root cause of any plant anomaly (process disturbance). this methodology also encompasses the integration, informatization, and visualization of process disturbances. efficacy of the proposed method was evaluated using a virtual VAM process developed through a dynamic process simulator. the results indicated that the designated KPIs effectively facilitated high-efficiency and decarbonized production by diminishing the quantity of monitoring elements and by expediting the process of cause detection
Biofuel production from microalgae has the problem of consuming large amounts of energy for centrifugation and drying when harvesting the microalgae. To avoid centrifugation, flocculants can be used to harvest microalgae from the culture medium. Furthermore, lipids can be extracted from wet microalgae by uning liquefied dimethyl ether (DME). However, the impact of flocculants on the lipid extraction process has not been studied, and there is concern that floc culants may contaminate the lipids and reduce the extraction yield. In this study, we recovered Pleurochrysis carteruew, a model species of microalgae, using three cationic polymer flocculants. Then, we investigated the impact of the floc culant on the lipid extraction by liquified DME. The results showed that high cationic flocculants decreased the yield of lipids, whereas low cationic flocculants did not inhibit lipid extraction by liquefied DME. Analysis of surface functional groups revealed that the flocculant did not contaminate the lipids. Therefore, the low cationic flocculant C510 could be used in conjunction with lipid extraction from Pcarteraew by liquefied DME.
