Basis For Optimization Research Articles

Land Use Changes and Its Impact on Ecological Environment Quality in Bayannur City

As an important ecological protective screen in northern China, monitoring and evaluating the dynamic changes in habitat quality and their relationship with land use changes in Bayannur played a notable role in maintaining regional ecological balance and species diversity. Based on the Google earth engine （GEE） platform, this study employed multi-period remote sensing image coupling to construct a remote sensing ecological index （RSEI）, analyzed the changes in habitat quality in Bayannur City from 2000 to 2022, and explored its relationship with land use changes. The results showed that： ① From 2000 to 2022, although the habitat quality of Bayannur improved slowly, the overall quality was poor. The annual change rate was 0.000 8 a-1 （P>0.05）, showing an insignificant upward trend, and the habitat quality in the south was significantly higher than that in the north. ② The changes of land types in Bayannur mainly occurred in Urad Middle Banner and Urad Back Banner. The changes in grassland area were the largest, followed by those of wasteland and cultivated land. ③ From 2000 to 2010, the increase in habitat quality in the study area was mainly related to the conversion of other land types to cultivated land and the conversion of wasteland and some cultivated land to grassland. From 2010 to 2022, the decrease in habitat quality was related to the shrinkage of grassland areas and the conversion of large areas to wastelands. ④ Grassland had the greatest impact on the rising and falling areas of habitat quality. For every 10% increase in grassland area, the rising area increased by 6.33%, and the falling area decreased by 4.58%. The research could provide a scientific theoretical basis for urban land pattern optimization, ecological environment management, and ecological civilization city construction in arid and semi-arid areas.

Design of CO2 Huff-n-Puff Parameters for Fractured Tight Oil Reservoirs Considering Geomechanical Effects

CO2-Huff-n-Puff (CO2-HnP) is an effective method for improving oil recovery in conventional reservoirs and has been widely applied to tight oil reservoirs. Recently, there has been a series of studies published on the oil increase mechanism and huff-n-puff parameter optimization of CO2-HnP. However, the understanding of the influence of fracture characterization, threshold pressure gradient (TPG), and geomechanical effects on CO2-HnP in fractured tight oil reservoirs is still limited. In this paper, a numerical model based on the embedded discrete fracture model (EDFM) was constructed to investigate the impact of TPG and geomechanical effects on cumulative oil production (COP). The effects of various huff-n-puff parameters, including bottomhole pressure, oil recovery rate, total CO2 injection amount, number of huff-n-puff cycles, timing of production transfer injection, production time, injection time, CO2 injection rate, and soaking time on the COP and oil replacement ratio were also explored in the paper. The results include the following: (1) The TPG and geomechanical effects led to significantly reduced COP. (2) A positive correlation with COP was found for parameters such as timing of production transfer injection and production time, while negative correlations were found for cycles, soaking time, and injection rate. For oil replacement ratio, soaking time and injection rate were positively correlated, while CO2 injection amount and number of cycles showed negative correlation. (3) With a constant injection volume, it is crucial to avoid an excessive number of cycles that reduce COP. On the basis of this parameter optimization, the oil replacement ratio can be enhanced by advancing the production transfer injection, shortening the injection time, and extending the soaking time. The findings can help optimize CO2-HnP strategies to improve oil recovery and economic benefits from the reservoir. This paper provides an effective numerical simulation method for CO2-HnP in fractured tight oil reservoirs, which has certain reference value.

Heterologous Biosynthesis of Taxifolin in Yarrowia lipolytica: Metabolic Engineering and Genome-Scale Metabolic Modeling.

Taxifolin, also known as dihydroquercetin (DHQ), is a flavonoid recognized for its potent antioxidant properties and a wide range of biological activities, including anti-tumor, antiviral, and immunomodulatory effects. Conventional extraction and chemical synthesis methods for taxifolin are often limited by low yields and associated environmental concerns. In this study, we investigated the heterologous biosynthesis of taxifolin in Yarrowia lipolytica through a combination of metabolic engineering and genome-scale metabolic modeling (GSM), complemented by flux balance analysis (FBA). We engineered Yarrowia lipolytica by introducing key biosynthetic genes and successfully synthesized taxifolin using naringenin (NAR) as a substrate, chosen for its low cost. Fermentation experiments demonstrated an optimal taxifolin yield of 10% at a substrate concentration of 200mg/L naringenin, with a maximum yield of 26.4mg/L taxifolin at 1g/L naringenin. To further enhance production, we applied a marker-free Cre-loxP-based gene integration method, allowing stable genomic integration of key genes, which increased taxifolin yield to 34.9mg/L at 1g/L naringenin. Additionally, intermediate metabolites eriodictyol (ERI) and dihydrokaempferol (DHK) accumulated to concentrations of 89.2mg/L and 21.7mg/L, respectively. Furthermore, we integrated metabolic data into a GSM and applied FBA to optimize the taxifolin biosynthetic pathway. Through Pareto frontier analysis, sensitivity analysis, flux variability analysis, and single gene deletion simulations, we identified key genetic modifications that significantly enhanced taxifolin yield. Overexpression of GND1 and IDP2 increased yields by 94% and 155%, respectively, while knockout of LIP2 led to a 46% increase. Using tri-baffled shake flasks to improve oxygen supply resulted in a 120% yield increase, whereas YPG medium decreased yield by 59%, validating our model's accuracy. To ensure stable and efficient gene expression, we integrated multi-copy constructs into the ribosomal DNA (rDNA) locus of Yarrowia lipolytica, doubling taxifolin production. These results demonstrate the effectiveness of GSM and FBA in addressing bottlenecks in microbial taxifolin biosynthesis and provide a basis for future optimization and large-scale production.

Efficient distribution network based on photovoltaic fed electric vehicle charging station using WSO-RBFNN approach

An integral and prevalent aspect of modern life is the electric vehicle (EV).EV charging networks struggle with power losses and high energy costs, particularly as demand rises leading to inefficiencies and potential system overloads. A hybrid WSO-RBFNN approach is proposed for the distribution network's photovoltaic (PV) fed electric vehicle charging stations. The performance of the proposed hybrid strategy is a combination of war strategy optimization (WSO) and Radial basis function neural network (RBFNN). It is hence referred to as the WSO-RBFNN technique. WSO optimizes the distribution network by minimizing power loss, improving voltage sensitivity, and reducing costs. Meanwhile, the RBFNN predicts the load demand. This innovative technique WSO-RBFNN identifies the nearest charging spots that minimize power loss and RBFNN optimizes power flow predicts charging demands and addresses both environmental and electrical grid stability concerns. The proposed technique is implemented in MATLAB. MATLAB is powerful computational software widely used in different fields like numerical computation, visualization, and algorithm development. MATLAB provides powerful tools for data visualization and plotting. The results are compared to various existing Heap-based optimizer (HBO), Wild horse optimizer (WHO), and Salp Swarm Algorithm (SSA) techniques. The proposed approach contributes only 0.59 % of a power loss it is less and the cost of energy is 0.18$ which is lesser and the voltage deviation is 6.6 pu which is less than the existing techniques.

Mathematical basis and toolchain for hierarchical optimization of biochemical networks.

Biological signalling systems are complex, and efforts to build mechanistic models must confront a huge parameter space, indirect and sparse data, and frequently encounter multiscale and multiphysics phenomena. We present HOSS, a framework for Hierarchical Optimization of Systems Simulations, to address such problems. HOSS operates by breaking down extensive systems models into individual pathway blocks organized in a nested hierarchy. At the first level, dependencies are solely on signalling inputs, and subsequent levels rely only on the preceding ones. We demonstrate that each independent pathway in every level can be efficiently optimized. Once optimized, its parameters are held constant while the pathway serves as input for succeeding levels. We develop an algorithmic approach to identify the necessary nested hierarchies for the application of HOSS in any given biochemical network. Furthermore, we devise two parallelizable variants that generate numerous model instances using stochastic scrambling of parameters during initial and intermediate stages of optimization. Our results indicate that these variants produce superior models and offer an estimate of solution degeneracy. Additionally, we showcase the effectiveness of the optimization methods for both abstracted, event-based simulations and ODE-based models.

Prerequisites for improving crop irrigation regimes on the basis of resource optimization

Prerequisites for improving crop irrigation regimes on the basis of resource optimization

Modern trends in the management of forage base organization in the conditions of digitalization of agriculture

The main approaches to the management of fodder resources are disclosed, taking into account the multidimensionality of fodder production and directions of growth of efficiency and sustainability of the fodder base. The analysis of feed resources use efficiency indicates the presence of reserves for optimization of rations in livestock breeding, which acts as one of the key factors in reducing excessive wear and tear of livestock and ensuring the necessary forage effect. The main directions of the use of digital solutions in the systems of fodder production are revealed, vectors for improving the management of fodder base organization on the basis of optimization and interaction of information flows of its functioning are determined.

Vulnerability Evolution Mechanism of High-Speed Railway Construction System in the Goaf Site of Qinshui Coalfield

The main reason for serious consequences caused by disasters is “insufficient emergency preparedness and obvious system vulnerability”. To ensure the safe operation and maintenance of the high-speed railway in goaf sites and achieve effective hierarchical management, the vulnerability theory was introduced, based on the system approach, to explore the characteristics of hierarchical evolution. Firstly, based on the analysis of the internal and external disturbances of the high-speed railway construction system with underlying goaf areas, the vulnerability characteristic elements were defined, and a conceptual vulnerability model was proposed. Secondly, based on the literature research, accident cases, and standards and specifications, 25 factors affecting vulnerability were identified and a two-dimensional cross matrix was used to establish a vulnerability evaluation index system. Then, ISM was used to build hierarchical relationships among indicators, analyze the vulnerability characteristics of direct factors, indirect factors and essential factors, and a vulnerability evolution analysis framework was proposed. Finally, the Taiyuan–Jiaozuo high-speed railway project was selected for hierarchical and progressive vulnerability management. The study analyzed the coupling effect and evolution mechanism of various elements of the safety management system under external disturbances, identified the weak links of the high-speed railway system in the goaf site, and provided a decision-making basis for continuous dynamic optimization and emergency response technology, which complied with the strategic policy of sustainable development.

Metabolomics reveal changes of flavonoids during processing of “nine-processed” tangerine peel (Jiuzhi Chenpi)

“Nine-processed” tangerine peel (Jiuzhi Chenpi) is a special snack in Guangdong, China, which is made by traditional and complex techniques. However, it is not clear how the flavonoid composition changes during its complex processing. In this study, we employed UPLC-ESI-Q Trap-MS/MS to comprehensively evaluate the alterations in flavonoids metabolites at four key processing stages: raw materials (CP1), soaking (CP2), curing (CP3), and aging (CP4). The results showed that total of 165 flavonoids metabolites were detected. Naringin, narirutin, hesperidin, neohesperidin and 3,5,6,7,8,3′,4′-heptamethoxyflavone were the top five compounds in terms of the relative content (>5.00%), and their relative content did not change significantly during processing. From CP1 to CP4, the relative content of 38 compounds, including 3′,4′,5,6,7-Pentamethoxyflavanone, apigenin 6,8-C-diglucoside, and diosmin, decreased continuously during processing. The relative contents of astragalin, naringenin-7-O-glucoside and apigenin-7-O-β-D-glucoside were increased by 2.06 times, 2.12 times and 3.34 times, respectively. Isorhamnetin-O-hexoside-O-pentoside (1.98%), 2,4,4′-trihydroxychalcone (0.43%), daidzein-hexoside-xyloside (0.03%), acacetin-7-O-galactoside (0.03%), chrysin-O-glucoside (0.01%), glycitein (0.01%), and prunetin (0.01%) were only detected in CP4. Correlation analysis showed that total flavonoids and naringin were significantly positively correlated with antioxidant activity. These findings offer valuable insights into the metabolites of “nine-processed” tangerine peel during processing and provide a basis for process optimization and quality control.

Ligand Many-Body Expansion as a General Approach for Accelerating Transition Metal Complex Discovery.

Methods that accelerate the evaluation of molecular properties are essential for chemical discovery. While some degree of ligand additivity has been established for transition metal complexes, it is underutilized in asymmetric complexes, such as the square pyramidal coordination geometries highly relevant to catalysis. To develop predictive methods beyond simple additivity, we apply a many-body expansion to octahedral and square pyramidal complexes and introduce a correction based on adjacent ligands (i.e., the cis interaction model). We first test the cis interaction model on adiabatic spin-splitting energies of octahedral Fe(II) complexes, predicting DFT-calculated values of unseen binary complexes to within an average error of 1.4 kcal/mol. Uncertainty analysis reveals the optimal basis, comprising the homoleptic and mer symmetric complexes. We next show that the cis model (i.e., the cis interaction model solved for the optimal basis) infers both DFT- and CCSD(T)-calculated model catalytic reaction energies to within 1 kcal/mol on average. The cis model predicts low-symmetry complexes with reaction energies outside the range of binary complex reaction energies. We observe that trans interactions are unnecessary for most monodentate systems but can be important for some combinations of ligands, such as complexes containing a mixture of bidentate and monodentate ligands. Finally, we demonstrate that the cis model may be combined with Δ-learning to predict CCSD(T) reaction energies from exhaustively calculated DFT reaction energies and the same fraction of CCSD(T) reaction energies needed for the cis model, achieving around 30% of the error from using the CCSD(T) reaction energies in the cis model alone.

Optimizing E-commerce Recommender Systems: A Comprehensive Review of Techniques and Future Directions

Abstract. This paper examines recommender systems in e-commerce by reviewing technologies and real-world applications and identifying the importance of big data analytics in recommender systems. In the study, three kinds of recommendation algorithms are discussed: collaborative filtering, content-based recommendation, and hybrid models. Collaborative filtering methods did well in the case of large-scale user data, but had cold-start and sparsity problems. Based on the content, recommended methods have strong personalized suggestion functions, but the information cocoon phenomenon is a risk, which decreases the contents diversity. Hybrid models are a combination approach between the two techniques, providing a flexible and robustness solution, but only a more complex computationally. This article also looks at the technology trends that have emerged lately, for example, the use of deep learning models, as well as the privacy-preserving techniques utilized in recommender systems. By analyzing and summarizing the existing research, this paper provides a reference basis for future optimization and application of recommender systems and points out potential research directions.

Prolonged cultivation enhances the stimulatory activity of hiPSC mesenchymal progenitor-derived conditioned medium

BackgroundHuman induced pluripotent stem cells represent a scalable source of youthful tissue progenitors and secretomes for regenerative therapies. The aim of our study was to investigate the potential of conditioned medium (CM) from hiPSC-mesenchymal progenitors (hiPSC-MPs) to stimulate osteogenic differentiation of human bone marrow-derived mesenchymal stromal cells (MSCs). We also investigated whether prolonged cultivation or osteogenic pre-differentiation of hiPSC-MPs could enhance the stimulatory activity of CM.MethodsMSCs were isolated from 13 donors (age 20–90 years). CM derived from hiPSC-MPs was added to the MSC cultures and the effects on proliferation and osteogenic differentiation were examined after 14 days and 6 weeks. The stimulatory activity of hiPSC-MP-CM was compared with the activity of MSC-derived CM and with the activity of CM prepared from hiPSC-MPs pre-cultured in growth or osteogenic medium for 14 days. Comparative proteomic analysis of CM was performed to gain insight into the molecular components responsible for the stimulatory activity.ResultsPrimary bone marrow-derived MSC exhibited variability, with a tendency towards lower proliferation and tri-lineage differentiation in older donors. hiPSC-MP-CM increased the proliferation and alkaline phosphatase activity of MSC from several adult/aged donors after 14 days of continuous supplementation under osteogenic conditions. However, CM supplementation failed to improve the mineralization of MSC pellets after 6 weeks under osteogenic conditions. hiPSC-MP-CM showed greater enhancement of proliferation and ALP activity than CM derived from bone marrow-derived MSCs. Moreover, 14-day cultivation but not osteogenic pre-differentiation of hiPSC-MPs strongly enhanced CM stimulatory activity. Quantitative proteomic analysis of d14-CM revealed a distinct profile of components that formed a highly interconnected associations network with two clusters, one functionally associated with binding and organization of actin/cytoskeletal components and the other with structural constituents of the extracellular matrix, collagen, and growth factor binding. Several hub proteins were identified that were reported to have functions in cell-extracellular matrix interaction, osteogenic differentiation and development.ConclusionsOur data show that hiPSC-MP-CM enhances early osteogenic differentiation of human bone marrow-derived MSCs and that prolonged cultivation of hiPSC-MPs enhances CM-stimulatory activity. Proteomic analysis of the upregulated protein components provides the basis for further optimization of hiPSC-MP-CM for bone regenerative therapies.Graphical

Construction of inherent geometric pattern for equal-area hexagonal discrete global grid systems

ABSTRACT Discrete Global Grid Systems (DGGSs) are hierarchical frameworks that provide seamless global coverage and enable the efficient processing and analysis of heterogeneous geospatial data. As cell resolution becomes finer, similarities in cell attributes, such as cell size and shape, increase. Understanding these shared characteristics enhances our knowledge of DGGSs structures, improving their reliability and accuracy across a range of applications. However, existing methods for quantifying these characteristics are limited, often emphasizing overall analysis and visualization rather than detailed assessment. This paper introduces a geometric pattern quantification method for equal-area hexagonal DGGSs by calculating inter-level attribute similarities to identify a reference level, segmenting the spatial distribution image at this reference level, and fitting the boundaries of these sub-images to create iso-feature lines. The results show that this method improves the accuracy and efficiency of cell attribute calculations, with enhancements of at least 5.6 times for study regions and 13.8 times for sample points at lower levels. This pattern provides a robust basis for grid selection and optimization in regional applications, promoting the broader adoption of DGGSs across various fields.

Dynamic Resource Allocation: The Geometry and Robustness of Constant Regret

We study a family of dynamic resource allocation problems, wherein requests of different types arrive over time and are accepted or rejected. Each request type is characterized by its reward, arrival probability, and resource consumption. An upper bound for the collected reward is given by a linear optimization problem with a random right-hand side. This type of problem, known as packing linear program (LP), is ubiquitous in resource allocation. We provide a detailed characterization of the parametric structure of this packing LP. Relying on this geometric understanding, we revisit and expand on BudgetRatio algorithms that achieve constant regret by resolving this same packing LP in each period and accepting requests scored as sufficiently valuable. We illustrate the benefits of the geometric view in proving that (i) BudgetRatio achieves constant regret relative to the offline (full information) upper bound in the presence of inventory that is (slowly) restocked, and (ii) within explicitly identifiable bounds, the algorithm’s regret is robust to misspecification of the model parameters. This gives bounds for the bandits version of the problem in which the parameters have to be learned. (iii) The algorithm has an equivalent formulation as a generalized bid-price algorithm in which the bid prices can be adaptively and efficiently computed. Our analysis focuses on the evolution of the remaining inventory—in turn of the LP that drives BudgetRatio—as a stochastic process. We prove that it is attracted to sticky regions of the state space in which the online algorithm takes actions consistent with the optimal basis of the offline upper bound, a basis that is revealed only in hindsight at the horizon’s end. Funding: This work was supported by the U.S. Department of Defense [Grant W911NF-20-C-0008].

Ecosystem Service Value Estimation and Ecological Security Pattern in Heilongjiang Province

To maintain ecosystem functions and ensure ecological security, estimating the value of ecosystem services and constructing an ecological security pattern are necessary. Considering the lack of systematic research on the estimation of ecosystem service value and the construction of ecological security pattern, this study extracted the ecological source based on the analysis of ecosystem service value and morphological spatial pattern. According to the natural conditions such as geographical location and altitude, land use type, landscape pattern type, elevation, slope, and normalized difference vegetation index were selected to establish the resistance surface. The minimum cumulative resistance model was used to identify potential ecological corridors, so as to construct the ecological security pattern of Heilongjiang Province, and longitudinal analysis was conducted from 2000 to 2020. The results showed that： ① The overall value of ecosystem services in Heilongjiang Province showed an upward trend （with an amplitude of 42%）, the value of hydrological regulation services accounted for the largest proportion among different service types （approximately 30%）, and the value of forest land services accounted for the largest proportion among different land use types （up to 70%）. ② Eight ecological source areas were extracted, mainly distributed around Greater Khingan Mountains, Lesser Khingan Mountains, Changbai Mountain, and Wanda Mountain, with the largest area of ecological source in Greater Khingan Mountains. ③ Twenty-eight potential ecological corridors were identified, mainly distributed in the northeastern side of the line from Heihe City to Mudanjiang City, forming densely populated areas in Qitaihe City, northern Mudanjiang City, and southern Jixi City. ④ An ecological security network pattern in Heilongjiang Province was constructed with Greater Khingan Mountains Region, Mudanjiang City, and Shuangyashan City as endpoints and Yichun City as the center, finding that the main problem faced at that time was uneven spatial distribution. The research results are helpful to formulate and establish more reasonable ecological environment protection measures and policies and can provide reference value and scientific basis for provincial ecosystem protection and optimization.

Fracture and fractal characteristics of high-temperature granite under confined space water jet impact

In the application of jet assisted deep drilling technology, the fracture mode and rock fragment characteristics of high-temperature rock in the confined space of jet drilling are not yet clear. We analyzed the fragmentation and debris distribution of high-temperature granite under confined space jet action using 3D reconstruction technology and statistical fractal theory to examine their fragmentation patterns and fractal characteristics. The results show that high-temperature rocks exhibit obvious thermal fracturing characteristics under the impact of confined water jet, and as the rock temperature increases, vertical compression shear cracks connect with radial tensile cracks. The maximum damage area is located near the bottom of the confined hole, and the distribution of cracks is more complex. As the degree of jet confinement decreases, the rock cracking form changes from radial tensile cracking to vertical compression shear cracking. As the rock temperature increases and the confined space size decreases, the total mass and large debris mass percentages of rock debris increase. The particle size distribution of rock debris follows an Rosin-Rammler (R-R) distribution and has obvious fractal characteristics. The fracture and fragmentation of high-temperature rocks under confined water jet impact are mainly caused by the combination of jet impact stress waves and thermal stress. The temperature difference of rocks affects the heat transfer between jet and rock, and the confined space size directly affects the heat transfer efficiency between jet and rock, which is manifested in different numbers of fracture cracks, internal damage area, and rock debris size distribution. These findings can provide a theoretical and parameter optimization basis for jet-assisted deep reservoir drilling applications.

Quantification of streamflow response to climate change and human activities within upstream mountainous areas of the Daqing River Basin, Northern China

The Daqinghe River Basin is located in the North China Plain. In recent years, however, climate warming, drying, and intense human activities have led to declining ecosystem functions and shrinking wetlands in the region. Understanding streamflow changes in the upstream mountainous areas of the Daqinghe River Basin in this changing environment and identifying the driving factors can provide a scientific basis for water resources management and optimization in these areas. This study focuses on the Beihedian River watershed, the Xidayang Reservoir watershed, and the Wangkuai Reservoir watershed in the upstream mountainous areas of the Daqinghe River. It is based on hydro-meteorological data collected between 1963 and 2019. The methods used in the study include the linear tendency estimation method, the non-parametric Mann-Kendall trend test, the elasticity coefficient method, and hydrological simulation methods. The results of this study suggest that the streamflow, precipitation, and potential evapotranspiration (PET) in the three watersheds showed an overall decreasing trend. The minimum precipitation decrease rate ranged from −1.09 to −0.55 mm/a, and the minimum streamflow decreasing rate at the Beihedian Hydrological Station was −1.32 mm/a, with a minimum range of 0–176.03 mm. Change-point analysis revealed that the streamflow in the Beihedian River and Xidayang Reservoir watersheds experienced a significant change point around 1999, with a significant level of α=0.05. As for the Wangkuai Reservoir watershed, a significant change point was observed around 1980, which is likely attributable to land system reforms and protective forest projects. The attribution analysis which combined both climate change and human activities using the elasticity coefficient method and hydrological simulation methods indicated that climate change contributed an average of 32.93%, 34.50%, and 35.12% to the reduction in streamflow in the three watersheds, respectively. Human activities accounted for an average contribution of 67.07%, 65.50%, and 64.88%, respectively. Water conservancy projects, afforestation, and other human activities were identified as the primary factors contributing to streamflow decreases.

DETERMINATION OF DOSE REFERENCE LEVELS AT BENDAN PEKALONGAN REGIONAL HOSPITAL FOR INTERNAL DOSE AUDIT AS AN EFFORT TO OPTIMIZE RADIATION PROTECTION FOR PATIENTS

Unnecessary exposure is less of a concern because it is considered not to cause injury to patients. Radiation protection optimization is carried out for patients to reduce unnecessary exposure. Following BAPETEN Regulation No. 4 of 2020 Article 46, permit holders are required to implement radiation protection optimization [1]. This study aimed to obtain the local dose reference level (TPD) value through an internal dose audit to optimize patient radiation protection. This optimization is carried out in several steps, including conducting an internal dose audit, determining the local TPD, and evaluating the examination. This study is expected to motivate documentation of radiation parameters to obtain sufficient data for analysis. The method used in this study is a literature study through related references and X-ray radiation output data to calculate the dose in the form of incident air kerma (INAK) and entrance surface air kerma (ESAK). The results showed that the local INAK TPD value was 52% below the national TPD, and the local ESAK TPD value was 57% below the national TPD. The expected local TPD value is a TPD value that is lower than the national TPD value. This indicates that the imaging protocol at RSUD Bendan has been well-optimized. However, there are still several types of examinations where the local TPD value exceeds the national TPD, indicating the need to review further the imaging techniques and protocols used. The influence of body weight and radiological image diagnosis was analyzed as a basis for further optimization. Thus, the determination of this local TPD can be an essential reference in efforts to improve patient safety and optimize radiation protection in health facilities. Keywords: radiation protection optimization of patient, Dose Reference Level (DRL), patient dose.

Influence of elevated temperature on the interfacial adhesion properties of cement composites reinforced with recycled coconut fiber

Magnesium phosphate cement (MPC) is the preferred material for rapid repair due to its rapid setting and early strength properties. However, its inherent brittleness renders it less suitable for use in assembled building nodes. To address the brittleness of MPC, coconut fiber (CF), a natural fiber known for its toughness, is often employed as a reinforcement. However, CF-MPC encounter difficulties in high-temperature settings, such as fire emergencies, which may compromise the interfacial bonding properties of this materials. This paper presents an investigation into the interfacial bonding properties of CF-MPC at elevated temperatures. The study employed microscopic analysis to observe the material changes of CF at elevated temperatures, evaluated the mechanical property changes by means of Fiber Tensile Test, and assessed the interfacial bonding performance by means of Fiber Drawing Test between CF and MPC. The findings indicated that as the temperature increased, the carbonized residue of the CF gradually decomposed, resulting in a notable decline in mechanical strength. Upon exceeding 400 °C, the carbonization of CF was complete, resulting in the loss of its mechanical properties. Besides the results also demonstrated that the interfacial bond strength of CF-MPC at a burial depth of 7.5 mm reaches its maximum value of 2.14 MPa at 20 °C. As the temperature rises to 200 °C, the interfacial bond strength at a burial depth of 12.5 mm reaches its maximum value of 1.08 MPa at this temperature. The findings of this study are conducive to promoting the application of CF-MPC at high temperatures and provide a theoretical basis for the subsequent optimization of this material.

New metrics for measuring 2D uniformity in stirring system based on reconstruction of the particle trajectory

In industrial mixing systems, the evaluation method is a crucial indicator for measuring mixing uniformity. This study proposes an assessment method that combines a method for positioning using dual cameras and a point pattern density fluctuation (PD) method based on disordered hyperuniformity. This study employs a method for positioning using dual cameras to investigate the motion trajectories of tracer balls and achieve a 3D reconstruction process. The reconstructed 3D systems are cross-sectioned through on the axis of the stirring paddle to form a 2D planar diagram of the tracer ball trajectories. The PD method is used to evaluate the mixing effectiveness of the 2D trajectory points, establishing evaluation metrics for the 2D mixing system. To ensure the accuracy of the PD method, a feasibility analysis was conducted using the conductometry. A relationship model between λ and mixing time was established, with a Pearson correlation coefficient (r) of -0.9867, indicating a strong negative linear correlation. The relationship between the planes and whole 3D space was analyzed in terms of the whole and the discrete perspective, as well as the existing methods were compared with other approaches. This study not only deepens the theoretical understanding of evaluating mixing uniformity but also provides a crucial foundation and theoretical basis for process optimization of stirring systems and design of stirred reactors. It offers valuable references and insights for engineering design and technological improvements in related fields.