Secondary Channel Research Articles

Attack-Dependent Adaptive Event-Triggered Security Fuzzy Control for Nonlinear Networked Cascade Control Systems Under Deception Attacks

This article investigates the issue of H∞ security output feedback control for a nonlinear networked cascade control system with deception attacks. First, to further reduce the amount of communication data, reasonably schedule network resources, and alleviate the impact of multi-channel deception attacks, an attack-dependent adaptive event-triggered mechanism is introduced into the primary network channel, and its adaptive triggered threshold can be adjusted according to the random attack probability. Secondly, the output dynamic quantization of the secondary network channel is considered. Then, a novel security cascade output feedback controller design framework based on the Takagi–Sugeno (T-S) fuzzy networked cascade control system under deception attacks is established. In addition, by introducing the Lyapunov–Krasovskii stability theory, the design conditions of the controller are given. Finally, the effectiveness and superiority of the proposed design strategies are verified by two simulation examples of power plant boiler–turbine system and power plant boiler power generation control system.

Distinguishing the XUV-induced Coulomb explosion dynamics of iodobenzene using covariance analysis

Abstract The primary and secondary fragmentation dynamics of iodobenzene following its ionization at 120 eV were determined using three-dimensional velocity map imaging and covariance analysis. Site-selective iodine 4d ionization was used to populate a range of excited polycationic parent states, which primarily broke apart at the carbon-iodine bond to produce I+ with phenyl or phenyl-like cations (CnHx + or CnHx 2+, with n = 1-6 and x = 1-5). The molecular products were produced with varying degrees of internal excitation and dehydrogenation, leading to stable and unstable outcomes. This further allowed the secondary dynamics of C6Hx 2+ intermediates to be distinguished using native-frame covariance analysis, which isolated these processes in their own centre-of-mass reference frames. The mass resolution of the imaging mass spectrometer used for these measurements enabled the primary and secondary reaction channels to be specified at the level of individual hydrogen atoms, demonstrating the ability of covariance analysis to comprehensively measure the competing fragmentation channels of aryl cations, including those involving intermediate steps.

Influence of pin fins and channel geometry on the hydrothermal performance of hexagonal mini-channel heat sink for cooling cylindrical batteries

This study numerically and experimentally examined the effects of pin fin configuration and channel geometry on the performance of a hexagonal mini-channel heat sink (HMCHS) to cool cylindrical lithium-ion battery cells. Various configurations of HMCHS with circular pin fins are studied, including circular fins centrally positioned within flat channels, circular fins positioned within grooved channels, circular fins situated within hybrid channels transitioning between wavy and straight channels and circular fins placed within hybrid channels that incorporate secondary flow channels between the primary flow channels. This numerical study utilized the finite volume method to investigate the laminar water flow at Reynolds numbers below 800. Findings showed that the HMCHS exhibited superior thermal performance compared with the conventional cylindrical mini-channel heat sink design. Moreover, the incorporation of pin fins into the HMCHS design was more effective in enhancing the Nusselt number than simply increasing the Reynolds number across various configurations. Meanwhile, the hybrid channel design with secondary channels, combined with the addition of pin fins, achieved the optimal overall performance of the HMCHS, resulting in the highest performance index of 1.88.

The Ca2+-activated Cl- channel TMEM16B shapes the response time course of olfactory sensory neurons.

Mammalian olfactory sensory neurons (OSNs) generate an odorant-induced response by sequentially activating two ion channels, which are in their ciliary membranes. First, a cationic, Ca2+-permeable cyclic nucleotide-gated channel is opened following odorant stimulation via a G protein-coupled transduction cascade and an ensuing rise in cAMP. Second, the increase in ciliary Ca2+ opens the excitatory Ca2+-activated Cl- channel TMEM16B, which carries most of the odorant-induced receptor current. While the role of TMEM16B in amplifying the response has been well established, it is less understood how this secondary ion channel contributes to response kinetics and action potential generation during single as well as repeated stimulation and, on the other hand, which response properties the cyclic nucleotide-gated (CNG) channel determines. We first demonstrate that basic membrane properties such as input resistance, resting potential and voltage-gated currents remained unchanged in OSNs that lack TMEM16B. The CNG channel predominantly determines the response delay and adaptation during odorant exposure, while the absence of the Cl- channels shortens both the time the response requires to reach its maximum and the time to terminate after odorant stimulation. This faster response termination in Tmem16b knockout OSNs allows them, somewhat counterintuitively despite the large reduction in receptor current, to fire action potentials more reliably when stimulated repeatedly in rapid succession, a phenomenon that occurs both in isolated OSNs and in OSNs within epithelial slices. Thus, while the two olfactory ion channels act in concert to generate the overall response, each one controls specific aspects of the odorant-induced response. KEY POINTS: Mammalian olfactory sensory neurons (OSNs) generate odorant-induced responses by activating two ion channels sequentially in their ciliary membranes: a Na+, Ca2⁺-permeable cyclic nucleotide-gated (CNG) channel and the Ca2⁺-activated Cl⁻ channel TMEM16B. The CNG channel controls response delay and adaptation during odorant exposure, while TMEM16B amplifies the response and influences the time required for the response to reach its peak and terminate. OSNs lacking TMEM16B display faster response termination, allowing them to fire action potentials more reliably during rapid repeated stimulation. The CNG and TMEM16B channels have distinct and complementary roles in shaping the kinetics and reliability of odorant-induced responses in OSNs.

Optimization of liquid film parameters of indirect evaporative cooling system based on machine vision

The wet channel plate surface of indirect evaporative cooler (IEC) cannot be completely wet in actual working conditions, and the plate surface parameters of liquid film wetting rate and liquid film thickness are difficult to observe, and the lack of relevant experimental research and data support. Therefore, in this paper, machine vision technology will be used to experimentally investigate the wetting rate and liquid film thickness of the secondary side channel of the IEC, and the UDF interface program and the parameters of the original simulation model will be enhanced. The results show that the average and maximum errors of the first and second outlet temperatures of the corrected analytical model are reduced compared with the original model, and the average error is within 5% under different spray flow rates.

Diagenesis Variation in Different Distributary Channels of Shallow Water Lacustrine Delta Deposits and Implication for High-Quality Reservoir Prediction: A Case Study in the Chang 8 Member in Caijiamiao Area, Sw Ordos Basin, China

Tight oil reservoirs are considered important exploration targets in lacustrine basins. High-quality reservoir prediction is difficult as the reservoirs have complex distributions of depositional facies and diagenesis processes. Previous research has found that the diagenesis process of tight oil sandstones varies greatly in different depositional facies. However, diagenesis variation in different depositional facies is still poorly studied, especially in distributary channels of shallow water delta deposits in lacustrine basins. Based on the description of core samples, the observation of rock slices, the interpretation of well logging data, and the analysis of porosity and permeability data, the differences in the lithofacies types, diagenesis processes, and pore structures of different distributary channels have been clarified. Ultimately, a model of diagenesis and reservoir heterogeneity distribution in the shallow-water delta of Chang 8 Member of the Yanchang Formation in the Caijiamiao area of the Ordos Basin has been established. This research indicates that the main distributary channels in the study area are dominated by massive bedding sandstone lithofacies, while the secondary distributary channels are primarily characterized by cross-bedding sandstone lithofacies. There are significant differences in the compaction, dissolution, and cementation of authigenic chlorite and carbonate among different parts of the distributary channels. Plastic mineral components, such as clay and mica, are abundant in sheet sands, and are more influenced by mechanical and chemical compaction. Influenced by the infiltration of meteoric water and hydrocarbon generation, dissolution pores are relatively well-developed in the underwater distributary channel reservoirs. A large amount of carbonate cementation, such as calcite and siderite, is found within the sandstone at the interface between sand and mud. The occurrence of authigenic chlorite exhibits a clear sedimentary microfacies zonation, but there is little difference in the kaolinite and siliceous cementation among different microfacies reservoirs. Finally, a model of diagenetic differences and reservoir quality distribution within dense sand bodies has been established. This model suggests that high-quality reservoirs are primarily developed in the middle of distributary channels, providing a theoretical basis for the further fine exploration and development of oil and gas in the study area.

Transformer-based dual-view X-ray security inspection image analysis

Artificial intelligence technology is rapidly advancing and has been widely applied in the field of intelligent security inspection. Utilizing computer vision technology to detect prohibited items in X-ray images has drawn much attention. Due to the transmission effect of X-rays, single-view security inspection images are prone to object occlusion and poor imaging angles, which seriously affects the performance of object detection models. Dual-view security inspection equipment can simultaneously capture X-ray transmission images of the item under inspection from both horizontal and vertical angles, which can effectively address issues of poor imaging angles and object occlusions that single-view imaging cannot resolve. In this paper, we introduced the artificial intelligence technology in dual-view security inspection image analysis, and proposed the dual-view feature fusion and prohibited item detection model in X-ray security inspection images based on the Vision Transformer framework. The detection model contains two input channels: the main and secondary channel. The main function of the main channel is to detect prohibited items in security inspection images, while the secondary channel is dedicated to providing effective feature information of prohibited items for the main channel. Two feature interaction modules are applied in the proposed model to realize dual channel information exchange and supplement from local and global perspectives respectively. Simulation results based on the public Dualray dataset have demonstrated the state-of-the-art performance of the proposed dual-view X-ray image detection model. Code is available at https://github.com/zhg-SZPT/Trans2Ray.

Carbon emission from the Lower Ob River floodplain during spring flood

Carbon emission from Arctic rivers constitutes a positive feedback between the climate warming and C cycle. However, in case of rivers with extensive floodplains, the impacts of temporary water bodies and secondary channels on CO2 exchange with atmosphere, compared to the main stem and tributaries, remain strongly understudied. In order to quantify the relative role of various water bodies of the Arctic river basin in the C cycle, the hydrochemical variables and greenhouse gases GHG concentrations and fluxes were measured within the floodplain of the largest Arctic River, Ob, in its low reaches located in the permafrost zone. These included the main stem, secondary channels, tributaries and floodplain lakes sampled over a 900 km north-south transect (25,736 km2 of the main stem and adjacent floodplain area; 7893 km2 water surface) during peak of spring flood (May 2023). In addition to main stem and tributaries, providing less than a half of overall C flux, floodplain lakes and secondary channels acted as important factor of C emission from the floodplain water surfaces. Multi-parametric statistical treatment of the data suggested two main processes of C emission from the Ob River floodplain waters: terrestrial organic matter-rich flooded wetlands (fens) provided elevated pCO2, whereas the sites of possible groundwater discharge in the secondary channels decreased the CO2 fluxes due to more alkaline environments, rich in labile metals and anionic elements.Based on available high-resolution Landsat-8 images, which matched the period of field work, it was found that the total water coverage of the floodplain during spring 2023 was 30 % of overall territory, compared to 18 % during the baseflow. Based on chamber-measured CO2 fluxes (1.56 ± 0.47 g C-CO2 m−2 d−1), overall CO2 emissions during 2 months of the spring flood from the entire Lower Ob River floodplain water surfaces including the main stem amounted to 0.73 ± 0.25 Tg C. Diffuse CH4 flux represented <1 % of total C flux. The main stem of the Ob River accounted for 34 % and 18 % of CO2 and CH4 emissions, respectively, whereas the floodplain lakes provided 59 % and 50 % of CO2 and CH4 emission, respectively. Considering that the low reaches of the Ob River represent >70 % of total river basin floodplain, and that during some years, the entire floodplain can be covered by water, emissions from the river – if assessed solely from summer (July–August) measurements – can be at least 3 times underestimated. It is therefore important to account for extended water surface during high water levels on Arctic rivers when assessing global riverine C emissions.

Mechanically Induced Motor Tremors Disrupt the Perception of Time.

Contemporary research has begun to show a strong relationship between movements and the perception of time. More specifically, concurrent movements serve to both bias and enhance time estimates. To explain these effects, we recently proposed a mechanism by which movements provide a secondary channel for estimating duration that is combined optimally with sensory estimates. However, a critical test of this framework is that by introducing "noise" into movements, sensory estimates of time should similarly become noisier. To accomplish this, we had human participants move a robotic arm while estimating intervals of time in either auditory or visual modalities (n = 24, ea.). Crucially, we introduced an artificial "tremor" in the arm while subjects were moving, that varied across three levels of amplitude (1-3 N) or frequency (4-12 Hz). The results of both experiments revealed that increasing the frequency of the tremor led to noisier estimates of duration. Further, the effect of noise varied with the base precision of the interval, such that a naturally less precise timing (i.e., visual) was more influenced by the tremor than a naturally more precise modality (i.e., auditory). To explain these findings, we fit the data with a recently developed drift-diffusion model of perceptual decision-making, in which the momentary, within-trial variance was allowed to vary across conditions. Here, we found that the model could recapitulate the observed findings, further supporting the theory that movements influence perception directly. Overall, our findings support the proposed framework, and demonstrate the utility of inducing motor noise via artificial tremors.

Islands in the stream: Wood‐induced deposition and erosion in the river corridor

AbstractLarge wood causes and responds to deposition and erosion within a river corridor. We focus on the anastomosing, gravel‐bed Swan River and two meandering, gravel‐bed tributaries in northwestern Montana, USA to explore the temporal dimensions of deposition and erosion associated with channel avulsions and island formation and to introduce the concept of wood levees. Channel avulsion represents isolation of part of the existing floodplain and formation of an anastomosing channel planform, with wood‐induced deposition at the point of channel bifurcation. Islands form at a wood jam that migrates upstream with time as sediment accumulates in the lee of the jam. The island creates only a local interruption of the single‐channel planform. We use tree‐ring and 14C dating to constrain wood‐induced island ages. We interpret the three wood‐induced forms of deposition and erosion that we describe here as reflecting a temporal continuum. Wood levees have primarily non‐woody vegetation and may be transient relative to the other features. Tributary islands appear to persist from a decade to over a century. Tree ages of 100–200 years at the floodplain avulsion site and the characteristics of the secondary channels suggest that these wood‐induced avulsion features can persist for more than a century. Understanding the temporal dynamics of wood‐induced features and spatial variation in erosion and deposition provides insight into the dynamics and spatial heterogeneity of natural river corridors, with implications for river restoration.

Universal Basic Income: Inspecting the Mechanisms

Abstract We examine the mechanisms driving the aggregate and distributional impacts of Universal Basic Income (UBI) through model analysis of various UBI programs and financing schemes. The main adverse effect is the distortionary tax increase to fund UBI, reducing labor force participation. Secondary channels are a decline in demand for self-insurance, depressing aggregate capital, and a positive income effect that further deters labor force participation. Due to these channels, introducing UBI alongside existing social programs reduces output and average welfare. Partially substituting existing programs with UBI mitigates the adverse effects, increases average welfare, but does not deliver a Pareto improvement.

Simulation study of flow and heat transfer in wavy microchannel heat sink with manifolds and secondary channels composite

With the continuous increase in power density of electronic devices, traditional cooling methods have gradually shown their limitations. Microchannel heat sinks (MCHSs) have enormous potential in thermal management for electronic devices due to their excellent heat dissipation performance. To improve the flow and heat transfer performance of MCHSs, a numerical study was conducted on 56 types of wavy microchannel heat sinks with manifolds and secondary channels composite (WMCHS-MSCs). The results indicate that compared to the original manifold wavy microchannel heat sink (MWMCHS), the optimal WMCHS-MSC increases the thermal enhancement factor by 45.1 % when the inlet volume flow rate Q = 1.0 × 10−6 m³/s. At the same time, the overall thermal resistance, the maximum temperature difference on the bottom wall, and the pressure drop of the optimal WMCHS-MSC are reduced by 7.6 %, 21.9 %, and 10.6 %, respectively. Compared to the original MWMCHS, the increase in Q for WMCHS-MSCs results in an overall trend of increased thermal performance, decreased temperature non-uniformity and hydraulic performance, and initially increased and then decreased overall performance. The flow field distribution of the secondary channels of WMCHS-MSCs intuitively demonstrates the improved hydraulic and thermal performance brought about by disrupting the thermal boundary layer and mixing the flow. The study presents a novel approach for the design of wavy MCHSs, potentially paving the way for enhanced thermal management solutions in electronic devices.

Evaluation of the Drainage Channel Capacity of Air Ukah in Ngabang

Flooding in Ngabang, Landak Regency, Kalimantan Barat often results from high rainfall, urban expansion, and limited drainage. This study analyzes the Air Ukah drainage system, including primary, secondary, and tertiary channels, to assess current capacities against projected rainfall intensities. Hydraulic and hydrological analyses were performed using primary field data and validated rainfall records from 1999-2020. Findings reveal that the existing drainage, with the primary channel’s 5.20 m³/s capacity, the secondary channel at 0.36 m³/s, and tertiary channels at 0.82 m³/s, cannot accommodate maximum discharge, particularly for a 100-year return period rainfall of 114.27 mm/hour. To address this, channels were expanded: the primary channel was widened to 6.5 m and deepened to 3.5 m, increasing its capacity to 11.83 m³/s. The secondary and tertiary channels were similarly upgraded, now accommodating 2.40 m³/s and a cumulative 34.07 m³/s. These modifications significantly enhance drainage capacity, preparing Ngabang to handle intense rain events and mitigating flood risks, particularly in urban areas. This upgraded system now meets the need for resilience against extreme rainfall, ensuring improved water management and community safety.

Experimental and theoretical evaluation of the effect of fluid resistance on the performance of a tubular indirect evaporative cooler

To evaluate the impact of fluid resistance on the performance of tubular indirect evaporative coolers (TIECs), a mathematical model of secondary air channel resistance was developed. An experimental setup was created to study the effects of factors such as secondary air flow rate and water spray flow rate on R2 under actual conditions. The model used the same conditions to analyze how factors like air flow, water flow, and droplet size influenced R2. The relationship between R2 and wet-bulb effectiveness (εwb) was also examined experimentally. The data from the experiments were compared to the model's predictions, showing a maximum relative error of 10 %, confirming the model's accuracy. It was found that R2 and secondary air flow rate (V2) are positively correlated, and εwb increases with R2. The experiments yielded secondary air resistances ranging from a minimum of 548.2 Pa to a maximum of 554.26 Pa. These results are valuable for selecting appropriate fans for the secondary air channel. Additionally, simulations were conducted to predict and calculate energy losses in the secondary air channel under real working conditions, providing a useful basis for future fan selection.

Redesign Drainage Channel in Jetis District Mojokerto Regency

There are up to 50-centimeter-high puddles on the road due to the Jetis Road Drainage Channel in Mojokerto Regency's incapacity to handle the flood discharge from the drainage catchment area. The Jetis Road drainage channel's size and channel bed slope will be affected by the meeting point of the 1000 m long secondary channel and the Jetis Road drainage outlet. The objective of this research is to evaluate the efficiency of drainage channel design considering the implications of the drainage existing condition due to inconsistent dimension and sedimentation. The drainage channel is designed to handle a total discharge of 4.6 m3/sec during 10 years return of period. Under these circumstances, a trapezoidal channel with a width of one meter and a depth of two meters is needed. The Jetis Road drainage channel's enlarged dimensions result in a flood water level of 1.8. The Jetis Road drainage channel has a freeboard of 0.2 meters since the flood water level that occurs in the channel with its new dimensions is 1.8 meters. The flow rate in the intended channel serves as the control in this study to determine channel size. The channel's maximum flow velocity of 1.44 m/sec satisfies the 1.5 m/sec maximum flow velocity allowed in concrete channels.

Numerical assessment of hydrothermal and entropy generation characteristics of graphene quantum dots nanofluid in a microchannel heat sink incorporating secondary channels and ribs

Efficient heat dissipation from electronic chips is essential for enhancing their performance and longevity. Significant progress has been achieved through the introduction of nanofluids and microchannel heat sinks. However, there is still a need for nanofluids that demonstrate exceptional thermal properties and stability. Graphene quantum dots nanofluid, an innovative carbon-based coolant with zero-dimensional nanostructures, presents promising features such as excellent chemical stability, surfactant-free preparation, superior thermal properties, and minimal impact on rheological characteristics. This study explores, for the first time, the hydrothermal behavior and entropy generation of graphene quantum dots nanofluid in a microchannel heat sink comprising secondary flow channels and ribs. To this end, a three-dimensional conjugate heat transfer model is built using ANSYS Fluent software, and the governing equations are solved using the finite volume method. The simulations are carried out considering temperature-dependent thermophysical properties under different concentrations ranging from 0 to 0.5 % and Reynolds numbers ranging from 100 to 500. The results reveal that the maximum bottom wall surface temperature decreases by 5.88 K, while the heat transfer coefficient improves by 24.9 % compared to the base fluid. Moreover, the total entropy generation reduces by 14.7 %. On the other hand, the pressure drop increases by 43 %. Overall, the highest increment in Performance Evaluation Criteria is 10.8 % at a Reynolds number of 100 and a concentration of 0.5 %, making this particular condition suitable for practical applications.

Numerical analysis of fluid flow and heat transfer characteristics in single crystal diamond microchannels with ribs and secondary channels

To meet the heat dissipation requirements of high-frequency and high-power electronic devices, single crystal diamond microchannels (SCD-MC) with secondary channels and rib combinations are proposed. The fluid flow and heat transfer characteristics in SCD-MC with various secondary channels and rectangular rib combinations are investigated through numerical simulations. The comprehensive performance and energy saving effect of the microchannel were evaluated by analyzing the factor of merit and entropy generation performance. The results show that the SCD-MC with secondary channels and rib combinations enhance fluid disturbance and increase the solid–liquid contact area, significantly improving heat transfer. When Reynolds number (Re) is 586, compared with the straight microchannel, the average temperature at the bottom of the SCD-MC with rectangular secondary channels and rectangular rib (Case 5) is reduced by 4.8 K, the heat transfer coefficient is increased by 209.8 %, and the factor of merit is improved by 89.2 %. The entropy generation augmentation number of the Case 5 microchannel was the minimum of 0.52, which has the highest energy saving effect. The factor of merit of the Case 5 microchannel exhibits a tendency to first increase and then decrease with the increase of the relative width of the secondary channel (Ψ), the relative width of the rib (Φ), and the relative position of the rib (Π). At Re = 586, Ψ = 0.933, Φ = 0.667, and Π = 0.5, the factor of merit of the Case 5 microchannel is 2.08, indicating the highest comprehensive performance. This finding provides new ideas and methods for the design and application of microchannel thermal management.

Historic channel dynamics of a highly developed dryland river

AbstractUnderstanding how river systems adjust to hydrologic alterations is critical to sustainable river management. Remote sensing and geographic information systems (GIS) provide a reliable and cost‐effective approach to studying river adjustment, including the possible attainment of dynamic equilibrium. We used this approach to study the highly managed lower South Platte River in northeastern Colorado, USA. We assessed the active channel (inclusive of open water, sand bars and adjacent sparsely vegetated areas) in three 30 km study sections, using General Land Office (GLO) maps circa 1870, and a time series of eight sets of aerial photographs from 1941 to 2015. In the GLO surveys, the active channel was 72–80% larger and 65–85% wider than in the later aerial photographs. Mean daily discharge in the prior photo interval was the strongest hydrologic predictor of channel area, while mean June daily discharge was the strongest predictor of channel width. Maximum daily discharge was the only significant predictor of lateral movement of the main channel. The highest rates of channel movement occurred when the primary channel switched locations to occupy a pre‐existing secondary channel. An average of 17% of the total active channel area was persistent, defined as consisting of channels at ≥7 of the eight photo years, and there was a narrow, persistent active channel throughout 68–72% of the length of each section. Thus, the location of the river has been stable since 1941, though flanking the channel location were areas of the active channel that were more temporally dynamic. After 1956, the post‐development lower South Platte River channel planform achieved a state of dynamic equilibrium, fluctuating thereafter within a relatively narrow range of values. As conditions in the basin change in the future due to increased municipal and industrial water demand and climate change, we can expect the river to also change.

The Rehabilitation of Dir-Polder Tambak Hanyar Irrigation Network on The Secondary Canal of The Tuan River in Banjar Regency

The rehabilitation of irrigation networks aims to increase water use efficiency. This includes repairing leaking or clogged channels so that water can flow more smoothly and precisely to where it is needed. A good irrigation network can also assist to manage rainwater better, thereby reducing the risk of flooding. The method of irrigation network rehabilitation in the Tambak Hanyar Polder for the Secondary Channel of the Tuan River, Banjar Regency is applied as follows (1) measuring the cross section of the Tuan River based on BM (Bench Mark) and PC (Point Control) depicted in the As Built Drawing, (2) preparing heavy equipment in the form of an excavator to remove mud or sedimentation deposits according to the depth measurements of the Tuan River, (3) evaluate the dimensions of the Tuan River secondary channel using measurements according to the project contract. Conclusion: Rehabilitation of the Tuan River secondary channel along 4050 meters of 7700 meters (contract reference) has been carried out. Rehabilitation of around 3650 meters was not carried out based on differences in work with reference to As Buit Drawing and Back Up Volume MC 100%. The reasons are (1) Technical Obstacles: Unpredictable weather and high rainfall intensity as well as the influence of sea tides on irrigation areas, (2) Non-Technical Constraints: Time is needed for socialization to the community regarding the implementation of rehabilitation and negotiations regarding the location for disposing of excavated soil and the position of residents' houses on the banks of the Tuan Secondary Channel River.

Optimization of Technical Calculation of Precast Wall Application for Kawo Secondary Canal Improvement in Sempor Irrigation Area, Kebumen, Central Java

This study aims to perform technical calculations using precast lining in the repair of secondary channels. The planning data used included a concrete grade of fc 18.68 MPa and a reinforcement grade of fy 500 MPa. The service condition analysis was carried out by taking into account the loading during the most critical condition, where the channel is empty and active soil pressure and external water pressure are the main loads. The fixed load calculation was the main focus, where the active earth pressure (PD) was calculated by considering the soil-specific gravity, soil shear angle, and soil coefficient. The calculation results show that the PD reaches 12.24 kN, which gives an idea of the load that the structure has to bear. Furthermore, the internal force analysis provides a deeper understanding of the moments occurring at specific points in the structure. For example, the maximum negative moment at point A was calculated by considering the moments due to fixed load and transient load, which reached 12.73 kNm. This research contributes to improving efficiency and safety in the application of precast lining for secondary channel improvement.