Small Trough Research Articles

Subsurface floats in the Filchner Trough provide the first direct under-ice tracks of the circulation on shelf

Abstract. Bottom water formation in the Weddell Sea and mass loss from the Filchner–Ronne Ice Shelf are tightly linked by the supply of Warm Deep Water to the continental shelf. Heavy sea ice cover and icebergs restrict ship access and upper-ocean measurements by moorings, compelling us to try new sampling methods. We present results from the first dedicated under-sea-ice float experiment tracking circulation on the continental shelf of the eastern Weddell Sea. Seven Apex profiling floats were deployed in 2017 at three different locations on the eastern Weddell Sea continental shelf, targeting the inflowing modified Warm Deep Water (mWDW), as well as the outflowing Ice Shelf Water (ISW). The floats capture a warm mWDW regime with southward inflow over the eastern continental shelf and a cold ISW regime with a recirculation of ISW in the Filchner Trough throughout the 4 years of observations. We provide the first Lagrangian in situ confirmation that the mWDW flowing onto the continental shelf follows two pathways: the eastern flank of the Filchner Trough and a small trough on the shallow shelf farther east. In the present circulation regime, this warm water is blocked from reaching the ice shelf cavity due to the presence of the thick ISW layer inside the Filchner Trough. The floats' trajectories and hydrography reveal the dynamically active front, flow reversal, and eddying motion between these two water masses along the eastern flank of the Filchner Trough.

Design and Characterization of a single-axis solar tracker system for Small Scale Parabolic trough collectors

ABSTRACT This paper introduces a detailed design and development of a solar tracker (ST) prototype for small-sized parabolic trough collectors (PTCs) with one degree of freedom. The PTCs are intended to produce industrial heat at a moderate temperature. The contribution of this work lies in its introduction of a new and optimized solar tracker, which prioritizes both accuracy and cost-efficiency in its design. This aspect was emphasized throughout the experimental investigation, along with a comparison of findings from existing literature. Therefore, the open-loop strategy based on the solar position algorithm (SPA) is adopted here to determine the tracking-elevation angle. A software algorithm is proposed and implemented in a control unit managed by low-cost board. Then, the tracking angle is updated by controlling the electro-mechanical system using an on-off hysteresis approach. An experimental characterization of the tracker is carried out regarding the tracking precision by directly measuring the errors in positioning angle and their impact on the optical losses. The obtained results show good performance of the tracker with a standard deviation of tracking errors of 0.55°, which is adequate for such collectors with tolerance angles of more than 2°. This makes the 96th percentile of the optical loss efficiency almost zero for our PTC.

Experimental Study on Optimal Recycling Mechanical Parameters of Cotton Field Mulch film based on Small Soil Trough System

Film mulching agriculture in arid areas is faced with pollution caused by film mulching, and currently mainly adopts the mechanized recycling of mulch film. However, residual mulch film in the soil will bind with soil under the farming environment, which affects the recycling effect. The main factors affecting the recycling of mulch film in the soil are not clear. In order to find out the specific factors, the actual dry-wet cycle water environment was simulated by using a small soil trough system based on the film lifting, separation and recycling problem of residual mulch film in the soil. The film lifting force and recycling efficiency of the residual mulch film under the action of wet-dry cycle were studied. The following results were obtained: soil compaction, film lifting angle, and the dry-wet cycle had a significant influence on the film lifting force value, indicating that the dry-wet cycle including water fertilizer had an impact on the soil structure. After mechanical loosening, the film lifting force decreased and the recycling rate of residual mulch film increased obviously. The optimal film recycling effect could be obtained under the following conditions, namely, a film lifting angle of 21.37–45.37°, the number of dry-wet cycles <3.8, a soil moisture of 22.43–23.18%, a soil compaction of 132.51–144.06 KPa, and a residual mulch film area of 45.85–64.5 cm2. The experimental results can provide technical reference for residual mulch film pollution control and mechanized recycling.

Multi-centric analysis of linear energy transfer distribution from clinical proton beam based on TOPAS

Linear energy transfer (LET), a key parameter of relative biological effectiveness (RBE) in proton therapy, is not easy to measure or simulate in a standardized protocol. A multi-centric analysis of dose-averaged LET (LETd) and track-averaged LET (LETt) including individual particle contributions, scoring slab thickness, inhomogeneous medium and clinical beam configurations are investigated using the Monte Carlo code TOPAS. Primary and secondary protons are scored separately within the simulation. It is found that the primary protons are the major contribution to LET at the dose plateau and Bragg Peak (BP) regions, whilst the secondary protons have complete contribution to the tail-LET beyond the BP. The calculated LETt is always lower than LETd, nearly a factor of two lower in the region distal to the BP. Varying the scoring slab thickness shows a negligible influence on LETt, whereas, there is up to 26% discrepancy in LETd at 5-cm depth with thicknesses varying from 0.1 mm to 2 mm for 153.3 MeV proton beam. Moreover, smaller scoring thickness of 0.1 mm results in large fluctuations for tail LETd. LETd distributions with 3-cm thick bone- and lung-slab at the entrance of water phantom against primary and secondary protons' contribution are derived. A small trough appears at the position of inserted inhomogeneous material and large spikes which could account for the changes of cross section in nuclear interactions by secondary protons display on the tail of LETd curve. Regarding the modulated beams, substantial-high LET values are obtained at both-sides along the beam path which should gain more attention when calculating LET in clinical applications. In conclusion, the selection of Monte Carlo simulation schemes indeed affects the calculated LET values, more procedures should be considered when building bridges between LET and radiological effectiveness.

Orbital angular momentum sidebands of Laguerre-Gauss beams reflecting on graphene metasurfaces

In this study, the orbital angular momentum (OAM) sidebands of Laguerre-Gauss beams reflecting on graphene metasurfaces are investigated. Upon reflection, vortex beams carrying orbital angular momentum will acquire sidebands, whose relative intensity varies depending on the Fermi energy, the external magnetic field, and/or the wave frequency. The relative intensity of the sideband OAM modes locally has a small trough for s-polarized beams at the topological transition point between the hyperbolic and elliptic topology. Energy can transfer from the central mode to the neighboring OAM modes increasing the topologic charge l. When the electric field of the incident s-polarized light occurs along the low energy dissipation direction of the graphene metasurfaces, it is helpful for the mode transformation of vortex beams. When the electric field of the incident s-polarized light occurs along the high energy dissipation direction, it is beneficial to suppressing crosstalk of different sidemodes in terahertz communication.

KOMPOSISI DAN LUAS RELUNG MAKANAN IKAN PALUNG (Hampala macrolepidota C.V.1823) DI WADUK PB. SOEDIRMAN BANJARNEGARA, JAWA TENGAH

This study aims to determine the composition and value of the natural feed niche of trough fish caught from the waters of the PB Reservoir. Sudirman. The research method used is a survey method with a sampling technique using purposive random sampling. The research location was divided into three stations, namely I (Karang Kemiri), II (Wanadadi), and III (Karang Jambe). Sampling was carried out three times (19 February, 07 March, and 2 August 2020). Data were analyzed descriptively comparatively. The results showed that the composition of the trough fish diet was dominated by Chlorophyta and plant debris. Based on the selectivity index and the most significant part of trough fish, including omnivorous fish. Large trough fish have a high food niche area. Small, medium and large trough fish have stiff competition for food in the waters

An environmental flow method applied in small and medium-sized mountainous rivers

In small and medium-sized mountainous rivers, there are usually hydropower stations in upper reaches as well as widened and heightened river sections in downstream reaches that are close to settlements. The environmental flow (EF) ensures river connectivity and the survival of aquatic organisms. The Tennant and wetted perimeter methods were used to calculate the minimum EF, and the R2CROSS criteria were used to evaluate the rationality of hydraulic parameters. The result shows that downstream areas with large cross-sections may suffer from shallow water depths, insufficient wetted perimeters, and poor overall connectivity of the water bodies, even under the standard EF discharges. A novel method was proposed to ensure EF and sustain suitable hydraulic conditions. The minimum EF calculated by the Tennant method is adopted as the design flow, and a small trapezoidal trough channel is excavated on the wide riverbed of an artificial river section. The width and depth of the small channel are calculated with Manning's equation. As a study case, this method was applied in the Fenglingang River in Zhejiang Province of China. A trapezoidal groove with a depth of 0.74 m and a bottom width of 0.52 m was excavated in the center of Fenglingang River to sustain EF and maintain river connectivity. This small channel not only prevents the river from cutoff, but also enables the water depth and wetted perimeter to meet the demand of aquatic organisms.

PSVI-26 Optimized small tissue specific protein isolation trough complexed diafiltration technique

Abstract Physiologically active and pure small tissue specific proteins are in demand in various fundamental and applied areas due to its bioactive properties. It is known that proteins can aggregate, as well as form a highly concentrated layer at the border of the filtration membrane or adhere to it, which significantly interferes with filtration. To eliminate these effects, protein-peptide extracts are recommended to be diluted, as well as using special agents, among them amino acids are more suitable for food industry. The purpose of the study is to develop the isolation and purification of proteins with molecular weight lower 50kDa from porcine hearts and aortas, using different amino acids and its combination. It was previously revealed, that family of fatty acid binding proteins (FABP) is one of the most stable and physiologically active protein in such raw materials. The final technology includes extraction, centrifugation, dilution of extract, diafiltration, lyophilization, dissolving in a small volume of distilled water, dialization and final drying. Concentration of 1.0% glycine and 0.1M proline in both diluted extract and exchange solution was revealed to be most effective to prevent protein aggregation. Dialysates were dried lyophilically and O’Farrell 2DE-electrophoresis with MALDI-TOF MS and MS/MS mass spectrometry identification were used. No proteins of 50kDa and bigger were detected. Proteins of lipid metabolism, peroxiredoxin 2, transgelins etc. with molecular weight lower 50kDa were found. The developed technology allows increasing cardiac and adipocytic isoforms of FABP family content. Cardiac isoform was previously identified in raw material, while adipocytic was newly detected. Adipocytic isoform content is lower than cardiac one; therefore, it was not detected in raw material, but application of complexed diafiltration technique led to increasing its content in dialysate. The developed technology can be used for separation and purification of animal proteins in native and stable forms.

Process variations of a Neoproterozoic delta system in response to the influence of mixed-energy systems and sea-level fluctuation: an insight from Simla Group, Lesser Himalaya, India

Deltas generally exhibit morphological and architectural variations due to repercussions of fluvial, wave and tidal currents. The Neoproterozoic Chhaosa Formation, Simla Group, Lesser Himalaya, a shallow-marine, mixed-energy deltaic system represents a unique example of variability of those processes at different scales. Outcrop-based facies analysis was combined with application of sequence stratigraphy in the present study to elucidate signatures of fluvial, tide and wave currents. The proximal part of the delta plain deposits (FA1) displaying fluvial attributes like sand sheets, large and small scale trough cross-beddings, channels, are combined with tidal activity. Delta front (FA2) deposits and prodelta deposits (FA3) essentially record mixed tidal and wave activity like mud drapes, flasers, lenticular, wavy beddings, syneresis cracks, tidal rhythmites, low angle cross-stratification oscillation ripples, hummocky and swaley cross-stratifications. Coastal process classification ternary plots are prepared to identify the interplay of different processes and their control in the deposition of Chhaosa delta system. The Chhaosa Formation has developed during elevated pulse rates of progradation and retrogradation, overlapped with elongated phases of progradation. A comparison between the Chhaosa delta and modern as well as ancient delta system has been made to understand the control of mixed-energy processes on sedimentation patterns throughout the global history.

THERMAL NUMERICAL INVESTIGATION OF A SMALL PARABOLIC TROUGH COLLECTOR UNDER DESERT CLIMATIC CONDITIONS

The main objective of this study is to conduct a controlled thermal investigation of a small Parabolic Trough Concentrator (PTC) under a real climatic conditions for El-Oued region on 16/03/2018, where the water was adopted as a heat transfer fluid. One-dimensional and transient energy balance equations have been analyzed, simplified and then programmed with the Matlab code. What distinguishes this study is the precise tracking of all heat coefficients that would give an accurate representation of the thermal behavior of the studied device. The average optical efficiency of the device has reached 78.55 %, the average value of the thermal efficiency has reached 74.30 %, while the average value of the overall coefficient of the thermal loss is 5.96 W.m-2.°C-1. Water steam has been formed under the effect of practical conditions between 10:20 and 11:50. The results obtained in this study encouraged the research team to start manufacturing this device with the dimensions mentioned in this paper, in order to direct this prototype setup to conduct scientific experiments will be in the field of solar cooling, desalination, water heating and other areas that serve the society welfare and maintain the environment integrity.

Numerical investigation of third-order resonant interactions between two gravity wave trains in deep water

Intense resonant interactions between two deep-water gravity waves can lead to the bending and then splitting of crests and troughs. The curvatures of the crests and troughs increase with an increase of the primary wave's steepness and the resonant wave's propagation distance. For primary waves with small steepness, the crest and trough lines will eventually split, as long as the propagation distance is sufficiently large. The crest line is split into a longer segment with a larger wave crest and a shorter one with a smaller wave crest.

Design and Performance of a Small Parabolic Trough System for Process Heat

Design and Performance of a Small Parabolic Trough System for Process Heat

Modeling and performance evaluation of a small solar parabolic trough collector (PTC) for possible purification of drained water

Small-scale solar thermal contaminated water purification is a promising green energy based decentralized process especially for rural area. The present work describes thermal performance estimation of a Parabolic Trough Collector (PTC) suitable for contaminated water purification. Contaminated drain water is pressurized through a slow sand filter and PTC with glass cover enclosing a copper tube. The diameter of the copper tube was estimated as 26 mm and that of the glass cover was 50 mm. The rim angle and width of the parabola were 60° and 1.2 m respectively. The PTC focal length, concentration ratio, overall heat loss coefficient was 493.4 mm, 13.93 and 7.39 W/m2K respectively. The maximum modeled and experimental thermal efficiency were about 60% and 55% respectively. Around water flow rate of 0.002 kg/s and solar radiation 750 W/m2, both water temperature and useful heat gain were maximum. The exergetic efficiency of the system increases with the increase of inlet temperature of water for different solar intensity. The solar purified water had all other parameters within acceptable limit except residual chlorine (0.24 mg/L).

To understand the plight of insects, entomologists look to the past

Plumbing a variety of historical data could offer important insights into trends in insect declines. When avian ecologist Nicholas Rodenhouse moved offices a few years ago, he found a potential treasure trove of data buried in some old file cabinets. Piles of forgotten spreadsheets catalogued taxonomic records of beetles collected in the hardwood forests of Hubbard Brook, NH, between 1973 and 1977. The research was originally meant to speak to the diets of local birds. Convinced that the spreadsheets could serve anther purpose, Rodenhouse, now emeritus at Wellesley College in MA, decided to ask his undergraduate mentee, Jennifer Harris, to resample the old research sites. Her work, conducted between 2015 and 2017, would tease a new story from the old data, one that could inform ongoing mysteries about how and why some insects seem to be disappearing (1). Some insect populations are declining—even ostensibly versatile species such as Central California’s large marble butterfly, Euchloe ausonides. Researchers are tracking trends through long-term insect count data and using historical data. Image credit: Joyce Gross (University of California, Berkeley). Harris collected beetles the same way the seventies-era researchers had done, using window traps: clear pieces of glass above a small trough of water. Beetles flying low to the forest floor hit the glass and fell into the water, drowned, and were later retrieved. Between 2015 and 2017, the researchers checked window traps at three different elevations twice a week from mid-May through early August and identified beetles to the family level. The mean number of individuals captured between trap checks declined by 83% between the 1970s and 2010s, and the number of beetle families fell by 39%. Nineteen families had disappeared entirely. Although insect populations normally expand and contract over time, disappearances across whole families are much more unusual. That so many …

Simulation and experimental investigation of a combined solar thermal and biomass heating system in Morocco

The integration of hybrid renewable energy systems, such as hybrid solar-biomass, to address thermal energy needs in various applications is a promising, efficient and eco-friendly solution that can be successfully applied for traditional baths in Morocco. Indeed, these systems are not widespread in Morocco, since traditional firewood furnaces are still commonly used for heating purposes in many different applications. Accordingly, the main objective of the study is to introduce a new hybrid solar-biomass system designed for space heating and hot water supply in a public bathhouse in Marrakesh, Morocco. This hybrid system includes small-scale pellet boilers and small dimension parabolic trough solar collectors (PTC), which is the first small-size PTC facility proposed for low temperature applications (less than 100 °C) in Morocco. Moreover, the preliminary simulation results of this hybrid solar-biomass system for space heating – case study – using TRNSYS software are presented. The use of such a hybrid system as a new design to retrofit conventional firewood boilers that are widely used for space and water heating in public bathhouses will lead to significant savings in firewood, which will contribute in particular to reducing deforestation in Morocco and will also result in substantial reductions in CO2 emissions.

Thermal energy management optimization of solar thermal energy system based on small parabolic trough collectors for bitumen maintaining on heat process

Solar energy integration in heat consuming processes is a promising replacement for fossil energy. We are interested in a small Solar Parabolic Trough Collectors field combined with a sensible heat storage reservoir. Unfortunately, such a system has a higher cost than fossil energy and is challenging to optimize. Therefore, this work's main objective is to provide an optimized design and management to minimize energy cost (EC) and maximize renewable energy utilization fraction (REF). This study is done by optimizing the sizing and the thermal energy flow management of a hybrid solar-fossil fuel energy system. The optimization problem is formulated based on mass and energy conservation equations, heat transfer phenomena modeling, correlations, and economic data. We resolved it by combining trial and error method, multi-node calculation procedure, and genetic algorithm. To evaluate our method, we studied a hybrid solar-fossil fuel energy system used for the bitumen heat maintaining process in Rabat region-Morocco. The evaluation considered different thermal storage capacities. Using our optimization, we reached REF ≥ 40% and EC < 0.05US$/kWh for small thermal capacities and REF ≥ 85% and EC less than 0.2US$/kWh for large thermal capacities. This is equivalent to saving, respectively, more than 0.75 and 1.5 tons of CO2 emissions/year/kW for small and large thermal storage capacities. Other important recommendations are also provided in this work.

Numerical assessment of the dynamic behavior of a solar-driven jet-ejector refrigeration system equipped with an adjustable jet-ejector

Abstract In the present paper, the mid-term performance of two different architectures of a solar-driven jet-ejector refrigeration system is numerically compared: the first one is fitted with a fixed-geometry jet-ejector while the second one is equipped with an adjustable spindle that modifies the jet-ejector area ratio. The jet-ejector behavior has been predicted with a validated computational fluid dynamics approach and the dynamic response of the overall system accounts for transient effects in a small parabolic trough collector and a hot thermal storage tank. The investigation shows that the adjustable jet-ejector allows for continuous and smooth operation in a much wider range of outdoor conditions. Additionally, it enables more efficient management of the thermal level in the hot storage system. As a result, the adjustable refrigeration system improves the performance indicators in all the warm months of the typical meteorological year under evaluation. The maximum improvement potential is found in May; the fixed-geometry system provides an average C O P th of 0.34 while the adjustable system reaches an average C O P th of 0.48 considering the same boundary conditions in both cases.

Design optimization, fabrication, and performance evaluation of solar parabolic trough collector for domestic applications

ABSTRACT In this paper, a brief study of small scale solar parabolic trough collector design, simulation, fabrication, and analyzed for heating water as a domestic purpose in the backward regions of developing countries are studied. During the designing phase, the solar parabolic trough collector aperture area was set as 1.5 m2 with 1 m wide and 1.5 m length. The design was done by using red laser light (631 nm) and stainless steel ruler template technique, then verified this design template with parabolic equation. After that, optimize the proposed design through Matlab simulation. Then fabricated the proposed design with different manufacturing techniques. Different experiments were conducted to analyze and evaluate the overall thermal performance of 1.5 m2 solar parabolic trough collector by placing it in two orientations i.e. East-West and North-South with respect to the sun tracking. The data were recorded and analyzed to check the overall efficiency and thermal performance of the system. The experimental results evaluated that efficiency and thermal performance of the solar parabolic trough collector was more when the focal line of the designed trough collector was placed in the East-West (61.66%) direction as compared to North-South direction (48.28%). Moreover, the designed collector raised the temperature of 100 liter water up-to 60°C within 5 hours of sunshine which is enough for four to five persons for bathing and laundry purposes in the winter season of backward and rural areas where there is a shortage of electricity and fossil fuels for domestic applications.

Lithofacies characteristics and depositional environment interpretations of the Middle Jurassic Fort Member rocks, Jaisalmer Formation, Western Rajasthan, India

The present study is focused on the identification of lithofacies characteristics and depositional environments for the Middle Jurassic sediments of Fort Member, Jaisalmer Formation, Western Rajasthan (NW India). Three facies associations are documented as tidally influenced fluvial, tidal/inter-tidal flat and wave-dominated shoreface facies deposits. Facies association-1 contains matrix-supported clasts, planar and flaser cross-stratified sandstone, interbedded sandstone and horizontal laminated sandstones; indicative of tidally influenced fluvial deposits. Facies association-2 characterized by herringbone cross-stratified sandstones, horizontal laminated sandstones, planar and trough cross-stratified sandstones, the alternate band of sandstone and shale, mud-crack sandstone developed on a tidal/inter tidally influence deposits. Facies association-3 consists of wave-dominated shoreface facies association consisting of wavy and lenticular beds, interference ripples, horizontal laminated sandstone, small scale planar cross-stratified sandstone, trough, and hummocky cross-stratified sandstone as well as fossiliferous limestone. Palaeoflow patterns from unipolar to bipolar indicate a change from tidal influence fluvial to marine depositional environments. The overall lateral and vertical distribution of lithofacies shows that the depositional environment was tidal-dominated fluvial channel to the marine realm.

Thermo-economic and exergy analysis and optimization of small PTC collectors for solar heat integration in industrial processes

This work presents an extensive analysis of the impact of operating and design parameters on thermo-economic and exergy performances of Small Parabolic Trough Collector (SPTC). The modeling equations system is developed based on thermodynamics and heat transfer phenomena, and it is resolved using a double fixed-point iterative algorithm and validated using experimental data from the literature. Moreover, an optimization work complete this study by using a new combined Fixed Point-Genetic Algorithm optimization method considering Rabat region (North: 34°00′47″, West: 6°49′57″-Morocco) as a case study. The objective function is expressed in such a way to minimize the total yearly cost of energy and maximize the collector exergy efficiency of the SPTC. The obtained outcomes of this work show that thermo-economic and exergy performances of the SPTC could be improved by reducing the collector length and receiver diameter and increasing the collector width. However, the mass flow rate of the heat medium impacts these performances differently. The optimization results prove that the integration of SPTC in industrial heat processes is a promising and very economical way to replace fossil fuels. Indeed, each single optimized SPTC (Aa = 10 m2; Width*Length = 2 m × 5 m) provides more than 12.84 MWh/year with an average unit cost less than 0.022 USD/kWh.