Upstream Side Research Articles

Experimental evaluation of water surface profiles upstream and downstream of a culvert with and without an apron

Culverts are structures designed to facilitate the transfer of water beneath roadways, effectively connecting two areas within a catchment. Several critical parameters influence the design of a culvert and its surrounding environment. Among these, the flow conditions and the management of water levels at both the inlet and outlet are essential for the culvert's operation, particularly regarding its performance during flood events. This article examines the impact of variations in the longitudinal slope of the culvert and the elevation of the downstream bed—both with and without an apron—on the flow profile entering and exiting the culvert. To investigate this, a series of 80 experiments were conducted in a straight laboratory channel under steady flow conditions. The objective of these tests is to analyze the water level profiles both upstream and downstream of the culvert under various scenarios. The results indicated that increasing the culvert slope led to a rise in water level on the upstream side of the culvert. Specifically, the maximum water level upstream increased by 14 %, 56 %, and 65.1 % when the culvert slope was raised from zero to 2.5 %, 4 %, and 5.5 %, respectively. Additionally, the minimum water level upstream also increased by 19.1 %, 70.6 %, and 83.1 % under the same slope changes. The average maximum and minimum water levels for all scenarios were calculated and compared. The findings of this research will be valuable for analyzing water transfer both upstream and downstream of the culvert structure, as well as for enhancing hydraulic c alculations related to its performance.

EFFECT OF UPSTREAM SIDE SLOPE OF CRUMP WEIR ON DISCHARGE COEFFICIENT

The current study examines the flow characteristics under free flow conditions over a crump weir. The impact of the side slopes of the weir on the coefficient of discharge (Cd) is taken into account. Four physical models with crest heights of 0.15 m under free flow circumstances and four upstream side slope (1:3, 1:2.5, 1:2 and 1:1.5) were used to investigate the impact of various variables on discharge coefficient (Cd). Using the dimensional analysis technique, the elements influencing the crump weir's discharge coefficient were determined based on laboratory tests. For the same flow rate, Cd value decrease by decreasing upstream side slope. It notices that a decrease in upstream slope (from 1:3 to 1:2.5) reducing Cd value about (2.61 %), decrease upstream slope from (1:3 to 1:2) reducing Cd value about (4.16 %) and when decrease upstream slope from (1:3 to 1:1.5) reducing Cd value about (5.81 %).

The Impact of the Formation of Petroleum Fund Policy on the Sustainability of Oil and Gas Activities in Indonesia

Business activities in the oil and gas sector certainly require high costs from upstream to downstream. From upstream to downstream of Indonesian oil and gas, the gap between production and consumption is getting wider, namely 616 thousand BOPD production and 1,471 MBOPD consumption and refinery capacity is still below the consumption figure, namely 1,151 million barrels per day. The need for high costs can be minimized by establishing a policy called the Petroleum Fund. This Petroleum Fund is taken from state revenues from the oil and gas sector for specific purposes to ensure the sustainability of oil and gas activities for future generations. Petroleum funds, especially in Indonesia, can be used for several important things such as investment capital on the upstream side to increase potential reserve status. On the downstream side, it can be used to increase refinery capacity so that fuel oil imports decrease. The fluctuating nature of oil prices is certainly a threat that must be overcome, this is anticipated by forming this policy so that fuel prices remain affordable for the public. Then efforts to reduce greenhouse gas emissions become an important thing that must be achieved by oil and gas companies as well as increasing human resource capacity in areas around the oil and gas industry.

Distinguishing fault offset from climatically modulated channel deflections: Insights from the Pearblossom slip-rate site, Mojave section of the San Andreas fault, California, USA

Fault slip histories are essential for understanding seismic hazard and regional fault system development but fundamentally depend on identifying, dating, and reconstructing displaced markers. Here, we use a case study of the Pearblossom site along the Mojave section of the San Andreas fault in California (USA) to show how pulses of sediment aggradation during wet periods can complicate such reconstructions by producing “imposter offsets”—landforms that develop with an initial deflection that is easily misread as tectonic displacement caused by fault slip. Specifically, we document two channels on the downstream side of the fault: a subtle one that we interpret to have been beheaded and displaced 24–49 m from a source channel on the upstream side of the fault, and a second and more prominent one that we interpret as an imposter offset of 36–88 m. Using optically stimulated luminescence dating, we determine that the source channel incised between 1.44 ± 0.43 ka and 1.27 ± 0.18 ka with a subsequent phase of alluvial fan aggradation at ~0.6 ka, when the channel with the imposter offset formed. Because the pulse of fan deposition coincides temporally with a wet period in Southern California precipitation records, we attribute formation of the imposter offset and the alluvial fan into which it incised to climatically modulated deposition at the site. Comparing precipitation records with charcoal ages compiled from multiple Mojave Desert region locations suggests that other slip-rate sites may be similarly affected. Although climatic effects can complicate slip-rate studies, we show that the morphology and upstream position of the deflected channel can indicate whether a site likely records useful information about fault slip.

Unveiling the Connection between the Alfvénic Oval and the Open–Closed Field Line Boundary at Ganymede

Alfvén waves generated by the interactions between the Ganymede magnetosphere and the fast-corotating Jovian plasma carry a significant amount of energy. This energy is partially transferred to precipitating particles, which correspond to a feature called the Alfvénic oval. However, the spatial distribution of the Alfvénic oval in the Ganymede system is unclear, and the physical correlation between the Alfvénic oval and the open–closed field line boundary (OCFB) has not been studied quantitatively. Using a high-resolution, three-dimensional global magnetohydrodynamics simulation of Ganymede's magnetosphere, we investigate the spatial distribution of the Alfvénic oval mapped on the ionosphere surface of Ganymede based on upstream measurements from Juno's PJ34 flyby. Our results show that (1) the simulated Alfvénic oval of Ganymede closely resembles the observed aurora oval, and although without kinetic physics, the magnitude of the simulated Afvénic Poynting flux is significantly lower than the estimation based on auroral luminosity; (2) the OCFB aligns closely with the poleward (equatorial) boundary of the enhanced Alfvénic power on the downstream (upstream) side; and (3) the magnetospheric flux tube convection pattern can guide the Alfvénic wave packet to propagate toward latitudes either equatorward or poleward of the OCFB on the downstream/upstream side. These results, presented for the first time in this study, provide testable predictions for both the ongoing Juno mission and future Jovian missions such as JUICE probing the minimagnetosphere system.

LINI HULU PRODUKSI SAWIT INDONESIA: PERSPEKTIF RANTAI PASOK

Smallholder oil palm plantations are still facing the challenge of solidity in increasing their collective action to influence the supply chain of the national and global palm oil industry. This study aims to analyze the upstream system of smallholder palm oil production in building the sustainability of the supply chain of the national palm oil industry from a supply chain perspective. The data collection method combines an empirical study approach and literacy. An empirical study was carried out to search for institutional portraits of farmers. Furthermore, the search for commodity flows and palm oil agro-industry actors was carried out using a supply chain scheme framework. Based on the discussion, it is concluded that the disclosure of the flow of information related to the volume, price, and supply value differs according to the stakeholders involved. The supply chain of upstream palm oil production starts from the production line of oil palm plantations to the fabrication of CPO/PKO and the fabrication of their derivatives. Oil palm farmers are the weakest parties in accessing prices, volumes, and purchasing capacity information. Independent and plasma oil palm plantation smallholders are the most vulnerable to problems of uncertainty, transparency, transaction costs, and institutions, as well as the determination of an undisclosed price share between the cooperative as an intermediary and the core company. The downstream supply chain of palm oil agroindustry (olein, biodiesel, and chemical industry) is dominated by stakeholders affiliating with national private plantation companies within the framework of vertical supply synergies. CPO/ PKO palm derivative processed agroindustry, which has no vertical affiliation with national plantation companies on the upstream side, was the weakest actor in dealing with uncertainty in the supply of raw materials.

Damage mechanism of model arch dam subjected to far-field underwater explosion

The dynamic response and damage modes of arch dams subjected to explosions are key topics having been extensively researched in recent years. However, the majority of research employs numerical simulation, and there is a lack of experimental investigations to further support those numerical simulation results. Given this, small-scale model experiments were conducted on the arch dam to investigate its dynamic response to underwater explosions. The findings of these experiments indicated a potential overall damage mode along the crown cantilever profile. A numerical investigation of the experimental arch dam was executed employing the CEL method in combination with the Concrete Damage Plasticity model. The damage development process and cracking mechanism of the arch dam under a far-field underwater explosion were examined. According to the numerical findings, the damage process to the arch dam resulting from a far-field underwater explosion might be divided into two phases: the shock wave action phase and the overall response phase. During the shock wave action phase, slight damage first appeared on the downstream dam face. Later, during the overall response phase, a crack spread from the dam base to dam crest and from the downstream side to the upstream side, eventually penetrating through the crown cantilever profile. The damage mechanism in the shock wave action phase is the reflected rarefaction wave off the downstream dam face causing localized tensile damage to surrounding concrete. While the cracking mechanism in the overall response phase is structural bending-induced tensile damage driven by the overall response.

Transcribing RNA polymerases: Dynamics of twin supercoiled domains

Gene transcription by an RNA polymerase (RNAP) enzyme requires that double-stranded DNA be locally and transiently opened, which results in an increase of DNA supercoiling downstream of the RNAP and a decrease of supercoiling upstream of it. When the DNA is initially torsionally relaxed and the RNAP experiences sufficiently large rotational drag, these variations lead to positively supercoiled plectonemes ahead of the RNAPs and negatively supercoiled ones behind it, a feature known as “twin supercoiled domain” (TSD). This work aims at deciphering into some more detail the torsional dynamics of circular DNA molecules being transcribed by RNAP enzymes. To this end, we performed Brownian dynamics simulations with a specially designed coarse-grained model. Depending on the superhelical density of the DNA molecule and the ratio of RNAP’s twist injection rate and rotational relaxation speed, simulations reveal a rich panel of behaviors, which sometimes differ markedly from the crude TSD picture. In particular, for sufficiently slow rotational relaxation speed, positively supercoiled plectonemes never form ahead of an RNAP that transcribes a DNA molecule with physiological negative supercoiling. Rather, negatively supercoiled plectonemes form almost periodically at the upstream side of the RNAP and grow up to a certain length before detaching from the RNAP and destabilizing rapidly. The extent to which topological barriers hinder the dynamics of TSDs is also discussed.

Experimental investigation on the mechanism of local scour around a cylindrical coastal pile foundation considering sloping bed conditions

Sea-crossing bridges are often subjected to local scour, significantly impacting the bearing capacity of the foundation system and potentially leading to bridge failures. This study presents experimental investigations of local scour around a cylindrical pile under different sediment slope conditions in unidirectional currents. Unlike previous studies that focused on horizontal sediment beds, this research explores the influence of inclined sediment beds, which reflect coastal and offshore topographies, which have some angles of inclination. Utilizing flume tests, the research investigates the evolution of scour depth, scour range, and the morphology of the sediment bed across various angles of inclination. The study also evaluates the effectiveness of a scour countermeasure involving rip-rap material around the pile on sloping beds. Specifically, a steeper inclination angle induces a faster flow velocity, resulting in increased scour depth at the upstream side of the pile and a reduced scour range at the downstream side due to backfilling. The countermeasure scenario reveals a significant reduction in both scour depth and range. This research provides analysis of the effects of inclined sediment beds, which reflect coastal topographies than horizontal ones, thereby providing insights for the design and protection of bridge foundations in diverse coastal conditions.

Structural insights into RNA cleavage by a novel family of bacterial RNases.

Processing of RNA is a key regulatory mechanism for all living systems. Escherichia coli protein YicC belongs to the well-conserved YicC family and has been identified as a novel ribonuclease. Here, we report a 2.8-Å-resolution crystal structure of the E. coli YicC apo protein and a 3.2-Å-cryo-EM structure of YicC bound to an RNA substrate. The apo YicC forms a dimer of trimers with a large open channel. In the RNA-bound form, the top trimer of YicC rotates nearly 70°and closes the RNA substrate inside the cavity to form a clamshell-pearl conformation that resembles no other known RNases. The structural information combined with mass spectrometry and biochemical data identified cleavage on the upstream side of an RNA hairpin. Mutagenesis studies demonstrated that the previously uncharacterized domain, DUF1732, is critical in both RNA binding and catalysis. These studies shed light on the mechanism of the previously unexplored YicC RNase family.

The streamgauging ruler: A low-cost, low-tech, alternative discharge measurement technique

The streamgauging ruler, a.k.a. transparent velocity-head rod, is an inexpensive, easy, and quick tool for conducting wading discharge measurements in open-channel flows. It provides reliable velocity and discharge measurements when the right measuring conditions, especially minimum flow velocity, are met. The principle is simple: depth-averaged velocity can be computed from the water level difference between the upstream and downstream sides of a plastic board placed into the flow perpendicular to the flow direction. The model developed by INRAE (commercially available for €210) is a little more expensive than previously published models but it significantly improves the ease-of-use and measurement quality. Comparison experiments with reference measurements performed in a laboratory flume and at various field sites confirm the accuracy of the semi-empirical velocity rating established by Pike et al. (2016). Over most of the investigated cross-sections, the discharge measurements are generally within 10% of the reference discharge, when the velocity is greater than 0.2 m/s. However, operator-related effects (site selection, number and distribution of verticals, adjustment and reading of the sliding rulers) can lead to larger errors, hence operator training and care are essential.A first evaluation of the velocity uncertainty related to the velocity-head reading is proposed in the form of an equation that can be used in existing methods for calculating discharge measurement uncertainty. As the method is extremely simple and quick, it is well suited for rapid discharge estimates, training or demonstration, citizen science programmes, or cooperation with services with limited resources and/or lacking specialized expertise in hydrometry. As of July 2024, 304 instruments had been built and released to diverse users around the world, along with a simple discharge computing spreadsheet, a video tutorial, and a field memo.

The Circular Path Towards Decarbonising the Li-Ion Battery Value Chain

The rapid transition to clean energy and electric mobility has led to an unprecedented demand for Li-ion batteries (LIBs), necessitating a comprehensive decarbonisation of their entire value chain to meet climate goals [1]. This talk takes a holistic view at the LIB production and recycling system to explore cradle-to-cradle decarbonisation strategies. The Life Cycle Assessment (LCA) framework is used to quantify the comparative importance of developments in battery manufacturing, raw material sourcing and battery recycling in reducing greenhouse-gas emissions (GHG) arising from the globally-distributed LIB value chain.On the upstream side, sourcing low-carbon materials is found to reduce the GHG footprint of LIB manufacturing by up to a factor of 4, depending on raw material type and source, and battery chemistry [2]. The geographical links between battery Gigafactory location and GHG emissions are also explored, revealing substantial differences between US states, Chinese provinces and European countries, traced to the carbon intensity of electricity generation [2]. On the downstream side, hydrometallurgical and pyrometallurgical treatment options for end-of-life LIBs are shown to achieve a GHG benefit of up to 40%, when recovered materials are circulated back to LIB production [3].The battery production and recycling LCA models are integrated to present a comprehensive sensitivity analysis on the effectiveness of LIB recycling in reducing GHG emissions. This is shown to depend on battery chemistry, with lithium iron phosphate material recovery achieving lower benefits, but also on the geographical specificity of key operations, directly affecting the type of materials being displaced through secondary routes. The talk concludes with an outlook to 2035, presenting scenarios to reduce the GHG emissions of the battery value chain through technological developments, improvements in manufacturing and the establishment of circularity.

Centrifuge modeling of levees with geocomposite chimney drain subjected to flooding

The objective of present study is to evaluate the performance of a levee subjected to flooding and seepage through centrifuge model tests. For this, six model tests were conducted on a 240 mm high levee model at 30g in a 4.5 m radius large beam centrifuge. A custom-developed simulator is employed to induce identical flood rates on the upstream side of models. Further, using (a) geocomposite (GC) and (b) sand-sandwiched geocomposite (SSGC) as internal chimney drain, the suitability of GC material for dissipation of pore-water pressure (PWP) is also studied. The results of the centrifuge tests are discussed in terms of the development of upstream flood function, PWP within the levee body, and the surface settlements at the levee's crest. Further, the influence of an internal chimney drain, the material used for its construction, and its type and composition on the seepage response of the levee are discussed. It is observed that a GC-based chimney drain with sand cushioning on both sides in the horizontal portion of the chimney drain performs well. Further, digital image analysis of SEM micrographs of exhumed GC after centrifuge tests and the analyzed PWP data during sustained flooding-induced seepage is found to corroborate well.

Understanding the impact of bridge structure on river morphology through geospatial techniques: case on Teesta River, Bangladesh

The primary priority of bridge construction over a waterway is to support and confirm constant communication. Conversely, it may locally disrupt the health of the river which will have an adverse influence on the hydrological as well as morphological behavior of nearby regions by way of the river’s narrowing. The current study evaluated the effect of bridge structure on river morphological characteristics for Teesta River. Hence to do, this work robbed two approaches. Firstly, the Landsat images from a pre-road bridge (2001 and 2006) and post-road bridge construction (2011, 2016, and 2021) are processed and used for bar formation and bank line shifting. Secondly, the bar properties, differences in channel width, and changes in river bank were evaluated using geospatial technology. The outcomes revealed a recurrent change of bar area and channel width at the upstream side of the bridges and likewise dominating at the downstream side. Throughout the post-road bridge period, the average bar area has increased noticeably by 32.45 sq.km which is 7.75% of the total river area and the downstream bar area has also increased considerably. Besides, both bank lines of the river were dominated by erosion in the post-road bridge construction era. Accordingly, the Teesta Road bridge’s existence has had a significant impact on the morphological modification in recent years. The study also reveals that the bars and islands of Teesta River undergo a drastic change and the river can be treated as a braided one, and also showed the minor trend of meandering. The findings of this research may be supportive for sustainable and long-term planning and development of the rivers and neighboring floodplains in Bangladesh.

The Bonney Coast upwelling: How physical processes shape the feeding behaviour of blue whales

This study employs a fully coupled physical-biological model to explore the oceanic dynamics and phytoplankton production in one of Australia’s most prominent coastal upwelling systems, the Bonney Coast Upwelling, that has barely been studied before. The study focusses on how physical processes provide two different food sources for blue whales (Balaenoptera musculus), namely, krill (treated as nonbuoyant particles) and zooplankton, both feeding on phytoplankton. While plankton grows in the euphotic zone in response to nutrient enrichment on time scales of weeks, krill can only be transported into the region via ambient currents. Findings of this study suggest that phytoplankton blooms appear slowly in the main upwelling plume on timescales of 4-8 weeks. Dynamical influences from incoming coastal Kelvin waves significantly weaken or strengthen this classical upwelling plume and its plankton productivity. On the other hand, the upwelling-favourable wind induces a continuous coastal current that also extends eastward past the Bonney Coast. This current operates to transport and distribute krill (that cannot swim horizontally) westward along the shelf, which explains the apparent conundrum why blue whales also feed on the upstream side of the upwelling plume. The author postulates that the variability of both plankton production and the intensity of the upwelling flow (passing krill swarms along the shelf) control the feeding locations of blue whales and other baleen whales on Australia’s southern shelves.

Modeling the Co-permeation of hydrogen isotopes through metals in all rate-limited regimes

Tritium safety plays a crucial role in D-T fusion engineering. During normal operations, tritium(T) is typically dissolved with protium(H) or deuterium(D) in structural materials. However, there are still controversial issues related to the synergistic isotopic effects when considering T permeation through metals with H/D. In this work, a numerical model is built to describe the co-permeation behavior of multi-component hydrogen isotopes through metals in all rate-limited regimes. This model involves isotope exchange reactions in the gas phase, molecular dissolution, and atomic recombination at the gas-solid interface, as well as the diffusion process in the bulk. By simulating the mixed hydrogen gas permeation through various metals, different results are observed. In surface limited regime, the effective permeation flux of D is slightly enhanced by the presence of H due to isotopic effect. In diffusion-limited regime, the recombination of heteronuclear hydrogen molecules (HD) will deviate the equilibrium concentration of D on the upstream side from Sievert's Law, thereafter suppressing the D permeation flux on the downstream side.

Quantitative evaluation using carotid ultrasonography-based high-frame-rate vector flow imaging in patients with low carotid stenosis.

To explore the role of quantitative evaluation using carotid ultrasonography (US)-based high-frame-rate vector flow (V Flow) imaging in patients with low carotid stenosis. This single-centre cross-sectional study consecutively recruited volunteers without carotid plaque and patients with low carotid stenosis from August 2022 to May 2023. Patients were divided into symptomatic and asymptomatic groups according to their head CT or MRI results within 8 weeks. All V Flow imaging examinations were performed using a Mindray Resona R9 US system. The wall shear stress (WSS) values, oscillatory shear index (OSI) values, and turbulence (Tur) indexes in the normal common carotid artery (CCA), normal carotid bifurcation (CB), and on the upstream and downstream surface of carotid plaque were measured. Pearson Chi-square test and Fisher exact test were used for counting data according to their type. For measurement data, independent sample t test and non-parametric rank sum test were used. The results proved that patients have higher WSS values and Tur indexes of CB than volunteers, and higher WSS values were detected on the surface of the plaques in symptomatic patients. What's more, the downstream side of the plaque was more vulnerable to plaque rupture than the upstream side due to more dynamic blood flow. Therefore, carotid US-based high-frame-rate V Flow imaging provides reliable mechanical biomarkers for assessing the haemodynamic change in patients with low stenosis. Our study may provide a new imaging tool for monitoring the progression of atherosclerosis and aiding the management of early atherosclerotic patients. Our study firstly investigated the difference of V Flow parameters on the surface of carotid plaques between symptomatic and asymptomatic patients with low carotid stenosis, which is expected to provide haemodynamic information and the mechanical basis for plaque rupture.

Exploration and application of welding technology for misalignment of pressure pipe orifices in a pumped storage power station

Abstract Pumped storage power stations are currently the most economical and clean large-scale energy storage method. Pumped storage power stations have flexible start and stop, rapid response, and have six major functions, including peak shaving, valley filling, frequency regulation, phase modulation, emergency backup, and black start. With the transformation of the energy system towards clean, low-carbon, safe and efficient, the operational characteristics of the power system will undergo significant changes, requiring sufficient flexible regulation of power sources and energy storage facilities. It is more urgent to accelerate the development and construction of pumped storage energy. Due to the characteristics of pumped storage installation, high-strength pressure steel pipes are required on the upstream side of the power station units as the water diversion pipeline. This article takes a pumped storage power station as an example to analyze and handle the problem of pipe misalignment encountered during the welding process of pressure steel pipes in the power station. Satisfactory results have been achieved, ensuring the welding quality and providing reference for other engineering projects.

Flood Prone Mapping based on Surface Runoff Analysis using the SWAT Model at the Upstream Side of Brantas

Flood Prone Mapping based on Surface Runoff Analysis using the SWAT Model at the Upstream Side of Brantas

Various Parameter Measurements in Single-Frequency Dual-ECR Heating on Electron Cyclotron Resonance Ion Source

We have been researching efficient generation of multi-charged ions on electron cyclotron resonance ion source (ECRIS). We can introduce microwaves from a coaxial antenna at the upstream side of the magnetic mirror field (Coaxial) and a rod antenna at the downstream side (Rod). Regardless of R-wave cutoff, ECR occurs at two resonance points by Dual-ECR heating which means introducing microwaves from both antennas and we succeeded in generating more multi-charged Ar ions. We measured beam currents and plasma parameters such as electron density and electron temperature and obtained their radial distributions. We found the beam currents of multi-charged Ar ions were highest by Dual-ECR heating.