Periodic Changes Research Articles

Wavelet-Based Method for Variations of Microplastics over a Monthly Lunar Tidal Cycle in Beach Sediments of Maowei Bay, China.

While microplastics from lake, beach and ocean environment has become a growing global concern, tidal variations of microplastics in beach sediments are not well documented. Here, sediments were sampled over one monthly lunar tidal cycle during low tidal period in Shajing Beach along the Maowei Bay, China. The shape and abundance of microplastics were measured in sediments to determine their periodic variations by wavelet analysis method. The results showed that microplastics are generally granule, fiber and film shapes on Shajing Beach. The dominant type was fiber, followed by the granule. Meanwhile, the microplastic abundances showed a periodic change about 15 days. The granule and fiber but not film also followed such periodic variations. Tourism and human activities along the bay are the most likely causes for microplastics in Shajing Beach, while half-mouth of tidal cycle is responsible for the periodic variation of microplastic abundances and types.

Changes in lake sturgeon spawning periodicity is associated with prior reproductive effort

Long-lived iteroparous organisms vary resource expenditures toward migration and reproduction in response to individual physical factors and conspecific interactions, which can affect future reproductive timing and interval. Reproductive actions can lead to trade-offs associated with allocations to current vs. future reproduction, including longer reproductive interval, require additional study. The objective of this study was to evaluate associations between physical stream characteristics, individual behaviors, and breeding demographics and spawning periodicity in lake sturgeon (Acipenser fulvescens). We used Radio Frequency Identification tags to monitor spawning migration by male (N = 1931) and female (N = 683) adults over seven consecutive years (2016 through 2022) in the Black River, Cheboygan Co., MI. We used ordinal regression models to quantify associations. Male spawning periodicity (1.60 ± 0.63 years; mean ± SE) decreased with increasing body size and intra-sex interactions and increased with increasing cumulative temperature, discharge, number of inter-sex interactions, and complete river migrations in a season. Female spawning periodicity (3.19 ± 0.05 years, mean ± SE) decreased with increasing upstream swimming time and inter-sex interactions. Results demonstrated spawning periodicity shortened as male lake sturgeon age, and future breeding opportunities decreased, while female periodicity may be more individualized and is more likely to be affected by resource acquisition.

Periodic Trends in the Incidence of Cleft Palate in a Cohort of Sri Lankan Cleft Palate Patients

Background: Over the last few decades the incidence of cleft palate has been increasing across the world. There are several genetic and environmental factors are reported to be among the causative agents of cleft palate. Theres scarcity of data with regards to the seasonality and the occurance of cleft palate among sri Lankans. Hence, the purpose of this study was to identify periodic changes in the incidence of cleft palate in a cohort of Sri Lankan population.Material & methods: Subjects (n=323) with cleft palate registered at the Regional Cleft Centre & Maxillo-Facial Department, Teaching Hospital, Karapitiya, Galle, from the 1st of January 2001 to 31st of December 2020 were included in the study. Structured interviewer based questionnaire was used to collect the information after obtaining the informed written consent.Results: Significantly higher number of cleft palate cases in this study were born in March (p = 0.008) compared with the national birth incidence while significantly lower numbers were born in October (p = 0.01). The sex ratio in the study sample was 0.71.Conclusions: The periodic trends in the incidence of cleft palate found in this preliminary study reinstated that environmental factors may have accounted for the reported seasonal variations observed in the incidence of cleft palate. Future studies are warranted to investigate the putative harmful seasonal factors that can influence the occurance of cleft palate.

Sex-dependent association of central circadian clock gene polymorphisms with clinical risk markers for noncommunicable diseases in the young population.

The circadian clock, which governs periodic physiological changes, is influenced by various environmental factors, and its disruptions can lead to non-communicable chronic diseases (NCDs). Among the genes that control the circadian clock are ARNTL, CLOCK, CRY1, PER1, PER2, NR1D2, and MTNR1B, with several polymorphisms associated with diseases such as diabetes and hypertension. Therefore, this study aimed to determine the association between SNPs in the aforementioned genes and markers of non-communicable chronic diseases (NCDs) in a young population, stratified by gender. A sample of 346 individuals of both sexes aged 18 to 27 underwent clinical and nutritional evaluations to determine clinical markers associated with NCDs. Using isothermal PCR, 119 polymorphisms in the ARNTL, CLOCK, CRY1, PER1, PER2, NR1D2, and MTNR1B genes were determined. Subsequently, binary logistic regression analyses and mean comparisons using Student's t-test and one-way ANOVA with Bonferroni adjustment were performed. Polymorphisms were associated with risk factors such as elevated waist circumference, BMI, insulin, and lipid imbalances, while some acted protectively. Notable SNPs included rs6486122, rs77486964, rs11022756, rs72869158 from ARNTL; rs7309618, rs10778528 from CRY1; rs2304911 from PER1; rs72620839, rs58574366 from PER2; rs6832769, rs1056547 from CLOCK; and rs4858095, rs11922577 from NR1D2, providing insights into the associations of genetic markers with clinically relevant markers for NCDs. Clock gene polymorphisms exhibit associations with clinical markers of NCDs, emphasizing the intricate interaction between the biological clock and risk factors. This underscores the importance of genetic testing and personalized clinical approaches for prevention and treatment. Further research is needed to understand the underlying mechanisms and long-term health impacts of these genetic variations.

Spatiotemporal Characteristics of Sea Level Changes in Hangzhou Bay over the Past 40 Years

To investigate the spatiotemporal characteristics of sea level changes in Hangzhou Bay over the past 40 years, we collected tide gauge data from six stations within the bay. Various mathematical and statistical methods, including linear regression, empirical orthogonal function (EOF) analysis, and wavelet analysis, were employed to reveal the long-term variation patterns and spatiotemporal characteristics of sea levels in Hangzhou Bay. The results show that the overall trend of sea levels in this area is characterized by a fluctuating rise, with the rate of rise at the top of the bay (Ganpu Station) reaching 6.74 mm/year, higher than the average rise rate of 3.5 mm/year along the coastal areas of Zhejiang Province. Since the 2010s, the rate of sea level change has accelerated. There is a significant seasonal variation in sea levels, with high values occurring in summer and autumn and low values in spring and winter. The sea level in Hangzhou Bay exhibits multi-timescale periodic changes, including astronomical tides, solar activity cycles, and seasonal cycles. It is projected that the sea level will transition from a rising cycle to a declining cycle after 2026. The rise in sea level in the open sea is the main factor contributing to the rising trend of sea levels in Hangzhou Bay. The contracted river for regulation and morphological evolution of the estuary have intensified tidal wave deformation, resulting in a significant impact on local sea level changes.

Elite-led Cultural Projects Manifesting Periodic Changes: Geoffrey Bawa Case Studies in Postcolonial Sri Lanka

It is often believed that the so-called ‘cultural projects’ are the most ideal form of political, economic and socio-cultural manifestation of a given society, at a given time. These are commonly referred to as ‘periodic changes’. In postcolonial Sri Lanka, it is often believed that cultural projects have been used to convey underlying messages to its masses by their patrons. Geoffrey Bawa – considered the most important architect of the nation who was responsible for its ‘national architectural style’ – completed a number of them in his career. It is often acknowledged that Bawa’s cultural projects themselves were instrumental indeed in making of the country’s aforementioned national style. On the other hand, the unmistakable role played by the governing/political elite (as patrons) behind the implementation of such projects is also noteworthy. Moreover, it is often said that the architecture of such cultural projects implemented by Bawa were associated closely with elite culture, but that of the masses they were meant for.In this light, the study narrates theories on elitism, and establishes positions of elite/masses in society respectively. Next, it assesses different levels of cultures, and then, their pertaining building design traditions respectively. In this process, the relationship between elite ‘high culture’ and ‘grand design tradition’ is also ascertained. Employing a qualitative research methodology, the study takes up three case studies by Geoffrey Bawa. The selected almost-parallel cultural projects with elite patronage are commonly viewed as the most instrumental from his portfolio for making the nation’s flagship architectural style by the 1980s. In terms of empirical work, to collect information, the study relies upon drawings, photographic surveys, and especially, literature. The gaps in literature are countered via secondary in-depth interviews based on semi-structured questionnaires, borrowed from literature. The selected architectural attributes (i.e. location selection/layouts as well as form constituents and architectural features/details) from each case study are then analyzed to determine their underlying design tradition/s respectively. Finally, the underlying reasons (i.e. periodic changes) behind their implementation are interpreted in a phenomenological viewpoint to draw conclusions.

The Impact Mechanism of Government Regulation on the Operation of Smart Health Senior Care Service Platform: A Perspective from Evolutionary Game Theory

Background: Smart health and senior care services have developed rapidly to cater to the aging society, but the corresponding regulations are not perfect. The platform and senior care service enterprises have chosen different strategies due to various factors, resulting in disorderly platform development and inefficient resource allocation. This research attempts to establish a regulatory mechanism to promote the active development of the platform. Methods: In order to mitigate opportunistic behaviors in the smart health senior care service platform, drawing from evolutionary game theory, this study establishes a decision-making model involving the government, the platform, and senior care service enterprises, and scrutinizes the evolutionary behaviors and equilibrium strategies of these three parties. Results: There are five equilibrium points among the three parties in the game, and the strategy selection shows periodic changes. The cost and level of positive government regulation, the conversion rate of smart aging construction services provided by the platform, penalties for opportunistic behavior by the platform, as well as the benefits of positive cooperation and penalties for passive cooperation by senior care service enterprises, will significantly affect the strategies of all parties involved. Conclusion: The research results indicate that establishing a regulatory mechanism for the smart health senior care service platform can promote effective cooperation between platform and senior care service enterprises. Active government regulation is the key to the smooth operation of the platform. Through quantitative analysis, the main strategic choices of participants in the smart health senior care service platform can be explained. This model can provide a reference for formulating policies related to smart senior care.

Lumbar temperature change after acupuncture or moxibustion at Weizhong (BL40) or Chize (LU5) in healthy adults: A randomized controlled trial.

There is a gap in understanding the effects of different acupoints and treatment methods (acupuncture and moxibustion) on microcirculatory changes in the lumbar region. This study aimed to assess the thermal effects of acupuncture at Weizhong (BL40), with acupuncture at Chize (LU5) and moxibustion at both acupoints as control interventions. In this randomized controlled trial, 140 healthy participants were equally divided into four groups: acupuncture at BL40 (Acu-BL40), acupuncture at LU5 (Acu-LU5), moxibustion at BL40 (Mox-BL40) and moxibustion at LU5 (Mox-LU5). Participants underwent a 30-minute session of their assigned treatment. Infrared thermal imaging was used to collect temperature data on the areas of interest for analysis. The primary measure was the change in average temperature of the observed area after the intervention. The secondary measures included periodic temperature changes every 5min and the temperature changes of the Governor Vessel and Bladder Meridian in the observed area after the intervention. Significant interactions were observed between treatments and acupoints affecting temperature (P<0.001). The Acu-BL40 group showed a notably higher increase in mean temperature after 30min compared to the Acu-LU5 and Mox-BL40 groups, with increases of 0.29 (95% confidence interval [CI]=0.17 to 0.41) and 0.24 (95% CI=0.08 to 0.41) °C, respectively. Acupuncture at BL40 acupoint can significantly increase the mean temperature in the observed area, highlighting the specific thermal effect of acupuncture compared to moxibustion in the lumbar area. This suggests a potential therapeutic benefit of acupuncture at BL40 for managing lumbar conditions. ClinicalTrials.gov (NCT05665426). Please cite this article as: Zheng SY, Wang XY, Lin LN, Liu S, Huang XX, Liu YY, Yu XS, Pan W, Fang JQ, Liang Y. Lumbar temperature change after acupuncture or moxibustion at Weizhong (BL40) or Chize (LU5) in healthy adults: a randomized controlled trial.J Integr Med. 2025; Epub ahead of print.

Widening of Wind Stress Anomalies Amplifies ENSO in a Warming Climate

Abstract Climate change simulations generally indicate the strengthening of El Niño–Southern Oscillation (ENSO) sea surface temperature (SST) variability through the twenty-first century, yet a robust physical mechanism explaining this change across different models is still lacking, and the projections for ENSO amplitude exhibit a large spread. Most commonly, changes in the background state of the tropical Pacific are invoked to explain these changes of ENSO. Here, we show that changes in the structure of wind stress anomalies associated with ENSO are potentially as important as these background state changes. Specifically, changes in the magnitude, meridional width, and zonal structure of wind stress anomalies can explain approximately 53% of the intermodel variance in the projected change of ENSO magnitude through the twenty-first century as well as 43% in ENSO periodicity changes. Among these changes in the wind structure, the meridional widening of wind anomalies plays the most important role. To demonstrate that these changes are indeed critical, we develop a hybrid model of ENSO based on the Community Earth System Model, version 2, which incorporates a dynamical ocean coupled to a simplified statistical atmosphere within the tropical Pacific. In the absence of external forcing and corresponding mean-state changes, the imposed changes in wind stress anomalies in this hybrid model result in an increase of ENSO amplitudes of nearly 10% along the equator. Our results are also theoretically supported by a recharge-oscillator model that incorporates the meridional wind structure. Thus, changes in the structure of wind stress anomalies, together with changes in the mean state, likely play a critical role in the projected strengthening of ENSO.

Fault Diagnosis and Optimized Operation and Maintenance of Drop-out Fuses in Alpine Regions Using MKL-SVM and GRU

Extreme climate in alpine regions leads to frequent failures of drop-out fuses, but existing methods have low detection accuracy and response speed. This article combines MKL-SVM (Multiple Kernel Learning-Support Vector Machine) and GRU (Gated Recurrent Unit) model to achieve precise fault diagnosis of drop-out fuses, leveraging their efficient processing of high-dimensional time series data. Sensors are used to collect data such as voltage, current, temperature, and wind speed. Based on GRU, global trends, temporal hidden states, and dynamic nonlinear features of the data are extracted as inputs for subsequent MKL-SVM. In MKL-SVM, a linear kernel function is used to simplify the linear relationship between static features; targeting temporal features, RBF (Radial Basis Function) kernel effectively captures dynamic trends, fluctuations, and periodic changes in temporal features. To further enhance the classification ability of the model, the kernel function parameters, including linear kernel weights and RBF kernel widths, are adjusted through cross-validation. Finally, based on the model diagnosis results and predicted data, an optimized operation and maintenance plan is formulated to reduce maintenance costs and improve equipment operating efficiency. The results show that the fusion model can significantly improve the reliability of fault detection and adapt to the unique environmental challenges of alpine regions. The accuracy of fault diagnosis for drop-out fuses is 95%, with an MSE (mean square error) value of about 0.15 and a maintenance cost reduction of about 21.89%. This method can achieve accurate fault diagnosis and efficient optimization of operation and maintenance under extreme weather conditions.

Online Media Attention to Coal Mine Disasters: An Analysis Based on the Issue Attention Cycle

The study examined the longitudinal development of coal mine disasters reported in news media in China. Around Issue Attention Cycle, issue competition (Issue Competition) and issue fatigue (Issue Fatigue) provides a way to analyze and explain the periodic changes in coal mine disaster reporting. The study indicates that media attention on coal mine disasters is low. The empirical results reveal that media attention goes through four stages of issue attention cycle model: the pre-problem stage, alarmed discovery and euphoric enthusiasm stage, decline in intensity of interest stage as well as post-problem stage. Applying scan statistics approach issue competition and issue fatigue are confirmed as the factors driving the fluctuation of media attention on coal mine disasters. Implications related to media agenda setting and public opinion on safety production were discussed based on the conclusions.

The clinical impact of chronopharmacology on current medicine.

One of the goals of clinical pharmacology is to optimize patient treatment by adopting new treatment strategies which will increase the efficacy of the treatment and decrease the adverse effects of the drugs. In the literature, it has shown that the effectiveness and toxicity of medications can vary significantly based on when they are administered, making timing a crucial factor in treatment plans. Chronopharmacology a relatively new branch of clinical pharmacology focuses on adjusting drug administration times to enhance patient outcomes. Chronopharmacology is largely influenced by an individual's circadian rhythm which refers to periodic changes in biological processes depending on the time of the day. The chronopharmacology influences clinical practice, and the accumulating knowledge in this field will likely lead healthcare providers to adopt new strategies for drug treatment regimens. This review aims to summarize the impact of chronopharmacology particularly on current clinical practices and highlight the latest findings related to chronophysiological mechanisms.

The role of ribosomal protein networks in ribosome dynamics.

Accurate protein synthesis requires ribosomes to integrate signals from distant functional sites and execute complex dynamics. Despite advances in understanding ribosome structure and function, two key questions remain: how information is transmitted between these distant sites, and how ribosomal movements are synchronized? We recently highlighted the existence of ribosomal protein networks, likely evolved to participate in ribosome signaling. Here, we investigate the relationship between ribosomal protein networks and ribosome dynamics. Our findings show that major motion centers in the bacterial ribosome interact specifically with r-proteins, and that ribosomal RNA exhibits high mobility around each r-protein. This suggests that periodic electrostatic changes in the context of negatively charged residues (Glu and Asp) induce RNA-protein 'distance-approach' cycles, controlling key ribosomal movements during translocation. These charged residues play a critical role in modulating electrostatic repulsion between RNA and proteins, thus coordinating ribosomal dynamics. We propose that r-protein networks synchronize ribosomal dynamics through an 'electrostatic domino' effect, extending the concept of allostery to the regulation of movements within supramolecular assemblies.

Impulsive thrust strategy for orbital pursuit-evasion games based on impulse-like constraint

This paper proposes a novel impulsive thrust strategy guided by optimal continuous thrust strategy to address two-player orbital pursuit-evasion game under impulsive thrust control. The strategy seeks to enhance the interpretability of impulsive thrust strategy by integrating it within the framework of differential game in traditional continuous systems. First, this paper introduces an impulse-like constraint, with periodical changes in thrust amplitude, to characterize the impulsive thrust control. Then, the game with the impulse-like constraint is converted into the two-point boundary value problem, which is solved by the combined shooting and deep learning method proposed in this paper. Deep learning and numerical optimization are employed to obtain the guesses for unknown terminal adjoint variables and the game terminal time. Subsequently, the accurate values are solved by the shooting method to yield the optimal continuous thrust strategy with the impulse-like constraint. Finally, the shooting method is iteratively employed at each impulse decision moment to derive the impulsive thrust strategy guided by the optimal continuous thrust strategy. Numerical examples demonstrate the convergence of the combined shooting and deep learning method, even if the strongly nonlinear impulse-like constraint is introduced. The effect of the impulsive thrust strategy guided by the optimal continuous thrust strategy is also discussed.

Breathers in Mode-Locked Lasers Based on Saturable Absorbers

Breathing pulses, as a unique nonlinear pulse phenomenon, play a key role in laser performance optimization, nonlinear optical processes, and complex signal transmission. Unlike stable solitons, the energy of breathing pulses fluctuates periodically over time, exhibiting periodic changes in both pulse frequency and amplitude. Through appropriate nonlinear effects, lasers can generate stable breathing pulses, achieving a mode-locked state that demonstrates a periodic "breathing" pattern. Based on this, a fiber laser incorporating a saturable absorber as the mode-locking element was designed and built, and stable breathing states were successfully observed at lower pump power levels. High-speed detection techniques and time-stretched dispersive Fourier transform (TS-DFT) technology were used to time-amplify and spectrally analyze the rapid pulses, while monitoring the evolution of the breathing pulse in both time and frequency domains. Experimental results indicate that changes in pump power significantly affect the periodic modulation induced by additional oscillations, thereby controlling the breathing ratio and ultimately leading to the formation of a stable soliton. When the pump power is between 470 &lt;i&gt;mW&lt;/i&gt; and 480 &lt;i&gt;mW&lt;/i&gt;, the formation of the breathing pulse was first observed, with a breathing ratio of up to 4.5. As the pump power increases, the breathing effect gradually diminishes, and at 510 &lt;i&gt;mW&lt;/i&gt;, it completely disappears, with the breathing ratio dropping to 1.&lt;br&gt;These results confirm the critical role of pump power in controlling the breathing pulse state and its transition, demonstrating the potential for controlling pump power in ultrafast laser technology and nonlinear optics. The breathing pulse phenomenon, as a periodic pulse behavior, reflects the complex dynamical characteristics between nonlinear optical effects and cavity parameters. When combined with the natural synchronization system formed between the breathing frequency and the cavity frequency (determined by the cavity length), the periodic change of the breathing pulse becomes a crucial factor for controlling laser output. By adjusting parameters such as the laser’s nonlinearity and dissipation, the characteristics of the breathing pulse and breathing ratio can be precisely controlled, thus achieving precise control of the laser output. The periodic oscillatory characteristics of the breathing pulse inside the laser cavity lead to the non-uniform distribution of pulses, a feature that demonstrates enormous potential in pulse shaping, ultrashort pulse generation, and precise frequency comb control. Additionally, the presence of the breathing pulse may impact the stability and energy conversion efficiency of the laser, offering new perspectives for laser design and optimization.

부산지역 출토 철모로 본 가야·신라의 창병(槍兵)운용

It is highly likely that the periodic change of the spearheads in the Three Kingdoms period projects changes in martial arts and further tactics. In order to find a clue to this part, this paper tried to estimate the operation method of the spearheads in the Three Kingdoms period, albeit weakly. As previously pointed out, spearheads in the Three Kingdoms period shares the common change of 'cross-sectional convex lens type → square type, having bar type → having no bar type, and flatted-soket type → tail of swallow-soket type' regardless of region, except for a few with strong decorative properties. This can be said to be the result of optimizing the function as a weapon. Therefore, in this paper, the discussion was conducted on the premise that regional differences were not noticeable in the case of the main spearheads for practical use. For a more detailed analysis, the regional scope was narrowed to target the representative ancient tombs of the Three Kingdoms period in Busan. First of all, through the analysis of the spearheads excavated from these relics, the form was set, and it was examined what types of spearhead that occupy the mainstream by period were examined. Next, we reviewed the functional characteristics of the spearhead that occupies the mainstream and examined fragmentarily whether this reflects changes in martial arts or tactics. As a result of the review, it was found that the operation of the Gaya-Silla spearman was divided into five stages. Stage I is the period from around AD to the second half of the 3rd century. Spearheads in the type of Ⅰ가A·Ⅰ가B of the cutting function is dominated. Stage II is the first half of the 4th century. Equations type of Ⅱ나B·Ⅱ나C appear anew. However, it is still confirmed that the spearheads of the cutting function is high in proportion, and spears(槍) and curved spears(曲刀), which are weapons for cutting other than spearheads, are identified. Stage III is the second half of the 4th century. Spearheads are scattered in many types, but among them, the amount of excavations of TypeⅡ나C of stabbing function is increasing. Stage IV is the period in the first half of the 5th century. TypeⅡ나C of stabbing function shows a high excavation rate. Stage V is after the second half of the 5th century. TypeⅡ나C and 무C of stabbing function dominate.

Geospatial Assessment of Trophic Status From a Dam Under Significant Agricultural Drainage at the Mid-Anatolia, Türkiye

The population of Anatolia is continuously growing and developing and it is under the deep influence of global warming. It is increasingly evident that more fresh water will be needed for drinking, irrigation and domestic use. This study aims to assess the water quality and trophic status of a dam (Bayramhacılı dam lake) under excessive agricultural irrigation threat using spatial and multivariate statistical analysis. In the study, the periodic changes in the eutrophic state of the dam lake were determined using global index categories, Carlson Trophic Status Index (CTSI = 66.7), Burns Trophic Level Index (BTLI = 6.4), and Shu Trophic State Index (STSI = 65.6). The two periodical averages of total phosphorus (TP), total nitrogen (TN), biological oxygen demand (BOD), (chemical oxygen demand (COD) and chlorophyll a (Chl_a) concentrations, which serve as an indicator of anthropogenic nutrient input, were determined to be 0.23, 31.28, 1.83, 8.99 and 48.1 µg/L, respectively. Trophic index distribution maps demonstrate that the dam’s surface water displays considerable alterations, particularly during the dry season. This evidence supports the implementation of a local management model that addresses the issue of eutrophication. It is therefore imperative that on-site measures are taken without delay.

Bahr Yousef meandering canal management – Hydraulic and morphological assessment

ABSTRACT Bahr Yousef is a meandering earthen canal and is considered one of the most morphologically active semi-natural streams in the west of River Nile region in Egypt. This stream is usually exposed to periodic changes in cross-sections due to scour, deposition, and improper periodic dredging activities. The objectives of the present study are to assess the morphological behavior and hydraulic performance of Bahr Yousef canal and to identify the flooding areas. Combination of field data, satellite images, and numerical modeling methods is used and achieved to simulate the dynamic behavior of the second reach of Bahr Yousef canal from Dahab regulator (km 77.700) to Saqoula regulator (km 179.450) under different flow scenarios. The designed, actual, and target flows were modeled using HEC-RAS modeling program to evaluate the canal’s hydraulic efficiency. The results showed that in the case of a passing target discharge, the flooded areas increased by 25.8%, and the most significant inundated areas are located between 135 km and 160 km along the studied reach. The canal narrowed by 5.8% from an average of 71.35 m in 2004 to 67.22 m in 2023 due to human activities and natural meandering phenomena. Significant sedimentation (10,671,870 m3) and erosion (4,593,143.67 m3) observed along the studied reach, restricting its capacity to handle target discharge. Recommendations are given to control the scour and sedimentation processes in certain critical curves along Bahr Yousef canal. This is very important to avoid inundation problems that have devastating consequences, including foundation collapses, crop damage, and property loss.

Feasibility Study and Economic Analysis for Hydroelectric-PV Hybrid System Performed with PVsyst Software

While energy demand is increasing day by day with the developing technology, the decrease in traditional energy sources and the negative effects of carbon emissions on the environment encourage countries to turn to sustainable and environmentally friendly renewable energy sources. Requirements such as the periodic change of renewable energy resources depending on weather conditions and the optimum use of existing resources have made it attractive to use different renewable energy resources together. In this paper, the feasibility study of a hybrid energy system for Akfen Renewable Energy's Gelinkaya Hydroelectric Power Plant (HPP) with an installed capacity of 6,866 MW, located in Aziziye district of Erzurum province. In the study, the economic analysis of the hybrid model resulting from the integration of Gelinkaya HPP with SPP (Solar Power Plant) using PVsyst software is discussed. The acceptance of Gelinkaya HPP by the Ministry of Energy was made on June 14, 2013 and the power plant started electricity generation activities. Since this date, the average annual electricity generation value of the power plant has been 10.062.411 MWh and the capacity factor has been realized as 16.73%. With the analysis of the HPP-SPP hybrid system, it was observed that the power plant was able to generate an average of 12.491 MWh more electricity per year by contributing to electricity generation, especially during irrigation periods, and the capacity factor increased to 37.50%.

Experimental Study on the Effects of Dynamic High Water Pressure on the Deformation Characteristics of Limestone

Difficulty in clarifying the deformation characteristics of deep rocks under a high water pressure environment is a technical bottleneck restricting the safe operation of large hydropower stations. In order to study the effect of reservoir water level changes on the mechanical behavior of deep limestone, a series of mechanical tests were conducted under different dynamic high water pressure environments using a self-developed hydraulic loading test device. The test results show that the unsaturated limestone always undergoes compressive deformation during the linear increase in external water pressure, and the saturated limestone changes its deformation state from compression to expansion during the linear decrease in external water pressure. The stress–strain curve of limestone shows apparent hysteresis characteristics during the cyclic increase and decrease in external water pressure. Overall, the rock strain rate showed a significant negative correlation with the external water pressure, and the rock deformation modulus showed a certain positive correlation with the external water pressure. During hydraulic loading, saturated rocks had a smaller range of variation in the strain rate and deformation modulus and were more resistant to deformation than unsaturated rocks. Limestone was subjected to both external water pressure and internal pore water pressure in a cyclic cycle, where pore water pressure promotes pore creation and expansion, while external water pressure prevents water from degrading the pore structure. The periodic change of water pressure has a significant influence on rock mechanics and deformation behavior, and the rock mass will undergo elastic deformation, plastic deformation, and even fracture. Further study of this deformation rule can provide a more accurate theoretical basis for the safe operation of water conservancy projects.