Secondary Channel Research Articles

A BLE 5.0 Extended Advertising Backscatter with Commodity Devices in Passive IoT Scenarios

BLE-based (Bluetooth Low Energy-based) backscatter has received considerable attention, as it aims to communicate with everyday smart devices such as smartphones, smartwatches, and tablets in passive IoT. The state-of-the-art BLE backscatter systems enable communication using a specialized continuous wave (CW) generator or entirely using commodity BLE 4.0 radios as an RF source. However, the existing BLE communication systems suffer from several key issues, including a short carrier length and a large frequency shift. This paper presents a passive BLE (PBLE) backscatter communication system that utilizes commodity BLE 5.0 radios. The system uses a BLE 5.0 extended advertising packet with partial single tones as excitations transmitting on the secondary advertising channel of BLE 5.0, and the BLE backscatter tag produces bandpass frequency-shift keying modulation at 1 Mb/s, which enables compatibility with BLE advertising channels. The prototype is implemented using an NRF52832 BLE 5.0 commodity chip, smart devices, and tags with FPGAS and chips. In FPGA board-level verification, when the downlink distance is 0.5 m, the uplink distance can reach 10 m. In chip testing, the uplink distance can reach 7 m when the downlink distance is 1 m. The baseband power consumption is 2 μW, with a total power consumption of 10 μW. This system eliminates the need for expensive and costly specialized RF sources, unlike the BLE backscatter communication system that uses a specialized CW generator. Compared to the BLE backscatter communication system that uses commodity BLE 4.0 radios, this system reduces the minimum frequency shift from 24 MHz to 2 MHz and increases the length of the single tones as a CW by a factor of about seven, from 31 bytes to 254 bytes.

Planning For Kucica Residential Drainage System in South Tangerang City Using SWMM Modelling

Planning an efficient drainage facility in residential areas is necessary to drain run-off water on the surface. To minimize the potential for inundation that can cause flooding. This research aims to design an efficient drainage system in one of the residential areas in BSD and to analyze the ability of drainage channels using the EPA SWMM 5.1 application for a 10-year return period. The results of this study for secondary channels with a maximum discharge plan of 0.101 m3/s can use a U-Ditch with dimensions of 30 cm × 40 cm, while primary channels with a maximum discharge plan of 0.288 m3/s can use a U-Ditch with dimensions of 40 cm × 60 cm. In this analysis only taking into account rainwater run-off from household sewage is not taken into account. In the main channel, using retention pond only can reduce around 12% of maximum discharge, so the alternative of flood prevention for this residential area can be implemented by using bio pore holes, which reduce 27.85% of maximum discharge. From these analyses, it can be concluded that the drainage system design can already accommodate the flood discharge, and adding retention pond does not affect decreasing flood discharge on the main channel too much.

Thermal performance improvement in wavy microchannels using secondary channels

PurposeThis study aims to minimize the pressure drop across wavy microchannels using secondary branches without compromising its capacity to transfer the heat. The impact of secondary flows on the pressure drop and heat transfer capabilities at different Reynolds numbers are investigated numerically for different wavy microchannels. Finally, different channels are evaluated using performance evaluation criteria to determine their effectiveness.Design/methodology/approachTo investigate the flow and heat transfer capabilities in wavy microchannels having secondary branches, a 3D conjugate heat transfer model based on finite volume method is used. In conventional wavy microchannel, secondary branches are introduced at crest and trough locations. For the numerical simulation, a single symmetrical channel is used to minimize computational time and resources and the flow within the channels remains single-phase and laminar.FindingsThe findings indicate that the suggested secondary channels notably improve heat transfer and decrease pressure drop within the channels. At lower flow rates, the secondary channels demonstrate superior performance in terms of heat transfer. However, the performance declines as the flow rate increased. With the same amplitude and wavelength, the introduction of secondary channels reduces the pressure drop compared with conventional wavy channels. Due to the presence of secondary channels, the flow splits from the main channel, and part of the core flow gets diverted into the secondary channel as the flow takes the path of minimum resistance. Due to this flow split, the core velocity is reduced. An increase in flow area helps in reducing pressure drop.Practical implicationsMany complex and intricate microchannels are proposed by the researchers to augment heat dissipation. There are challenges in the fabrication of microchannels, such as surface finish and achieving the required dimensions. However, due to the recent developments in metal additive manufacturing and microfabrication techniques, the complex shapes proposed in this paper are feasible to fabricate.Originality/valueWavy channels are widely used in heat transfer and micro-fluidics applications. The proposed wavy microchannels with secondary channels are different when compared to conventional wavy channels and can be used practically to solve thermal challenges. They help achieve a lower pressure drop in wavy microchannels without compromising heat transfer performance.

Distribution of logjams in relation to lateral connectivity in the River Corridor

We examine the redistribution of logjams from the channel to the floodplain during a large flood following a wildfire in a forested montane catchment, conceptualizing redistribution with respect to changes in connectivity within the river corridor during and after the flood. A 2020 wildfire burned much of the 40 km2 Little Beaver Creek catchment at high severity. A flash flood in July 2022 completely inundated the river corridor and moved substantial amounts of large wood from the channel onto the floodplain. Floodplain logjams were largely absent prior to the flood. Forty-two channel-spanning logjams remained in the channel after the July 2022 flood, compared to 91 before the flood, and only 4 of these created backwater at base flow. Most of the large wood present in the river corridor was redistributed into 700 floodplain logjams, most of which were pinned against tree trunks. Multivariate linear models indicate that floodplain jam distribution density (number of logjams/ha surface area) correlates most strongly with floodplain forest basal area and floodplain/channel width ratio. Prior to the July 2022 flood, channel-spanning logjams limited longitudinal connectivity within the active channel but enhanced vertical connectivity via hyporheic exchange and lateral connectivity via formation of secondary channels and obstruction-inducing overbank flows. The enhanced transport capacity of the flood removed or altered most of these logjams, increasing longitudinal connectivity. Complete inundation of the floodplain during the July 2022 flood represented a transient increase in lateral connectivity. The formation of floodplain logjams and secondary channels, along with localized floodplain erosion and deposition, created more persistent alterations in lateral connectivity. Our observations suggest that logjams can increase lateral connectivity within the river corridor by deflecting flow in a manner that creates persistent secondary channels. Although secondary channels might have formed in Little Beaver Creek during the 2022 flood without the presence of logjams, the flow obstructions created by even relatively transient logjams likely increased the formation of a multichannel planform and the associated persistent lateral connectivity.

Optimization Analysis and Design of Electromagnetic Matching Characteristics of Nano Radar Wave Absorbing Materials Based on Computational Intelligence

Nanometer radar wave absorbent is a new type of absorbent with great development prospect, which has important application demand in radar wave application. However, there are great differences in the practical application effects of different nano-radar wave absorbing materials, so it is necessary to optimize and analyze these differences, and the emergence of computational intelligence technology supplements this work. One of the great advantages of computational intelligence is that it does not rely on the correct model of the system when dealing with performance issues, and is affected by a variety of organisms and biota through algebraic methods. The high-level intelligent system with strong cognitive behavior awareness makes each algorithm have the characteristics of parallelism, social behavior, unit intelligence, openness and so on. Based on computational intelligence, this study analyzes the electromagnetic matching characteristics of nano-radar absorbing materials and concludes that: (1) An absorber cell structure with a tunable interface is designed using the tunable FSS bandpass to replace the previous fixed FSS bandpass. The results show that the transmission rate can be adjusted in a certain range and the input loss is low. Meets the design requirements of a customizable absorber. (2) In order to improve the impact force of nano-absorbing materials, it is necessary to analyze the similarities and differences with others, and process the life information after identification. The improved computational intelligence model can extract and analyze the information efficiently and quickly. (3) Under the same thickness of the design, the single-layer fabric has higher electric wave intensity, but the frequency band is narrower, while the double-layer fabric has higher electric wave input bandwidth. Electrical carbon black can be filled with magnetic nanomaterials to enhance radio wave performance. The composite material has very good electric wave mixing performance, and the polar grinding composite nano material is very suitable for improving the magnetic property and the uniformity of the carbon black particles. (4) For a particular secondary channel, consider using a fast numerical algorithm to optimize the path based on the curvature of the key channel. Proper planning in a robotic approach can not only perform the required tasks efficiently, but also improve performance, reduce workload, and extend the lifetime of the robot.

Performance evaluation of a passive air conditioning module integrating radiative sky cooling and indirect evaporative cooling

Amidst escalating global warming challenges, the demand for sustainable, carbon-free cooling technologies in buildings has become pressing. While radiative cooling (RC) and indirect evaporative cooling (IEC) are carbon–neutral, their efficacy is constrained by a limited cooling capacity. This study introduces an innovative passive air conditioning module that integrates RC and IEC to boost efficiency. The RC-IEC module unifies the air-conditioning process in both the RC and dry channels of the IEC unit, ensuring air cooling with a constant humidity ratio. A portion of the IEC dry channel outlet air is redirected to the wet channel to augment the efficiency of the IEC process. The outlet air from the wet channel is directed to the secondary RC air channel for cold energy recovery instead of being directly exhausted. The developed mathematical model, validated with experimental data, demonstrates that the RC-IEC system lowers the supply air temperature by 0.88 °C compared to the IEC-only system. This corresponds to an 11.91 % and 9.94 % improvement in dew-point effectiveness and cooling energy gain, respectively. A parametric study indicates the system's suitability for hot, arid climates, with optimal performance at a wet channel air mass fraction of 0.31. The analysis of the annual cooling performance of the RC-IEC system across diverse climates, spanning from Athens to Singapore, spotlights Dubai's system as the most efficient, achieving a remarkable annual gain of 1081.09 MJ. The study emphasizes the need for tailored strategies, such as advanced air dehumidification technologies, to optimize cooling in humid regions like Singapore.

PENGARUH PASANG SURUT DISALURAN PADA KAWASAN PERSAWAHAN

Tides are a natural phenomenon of periodic rise and fall of water levels caused by gravitational forces and the force of attraction. This can naturally increase water levels and floods which are usually called tidal floods.To overcome this, drainage was created to reduce overflow at high tide and add water at low tide.The Lalan Sub-Watershed, Lalan District, Musi Banyuasin Regency is one of the sub-watersheds of the Musi Watershed which is influenced by tides. The average height of secondary channels in the Lalan sub-basin is 1.15 m with an average flow discharge of 528.96 m3/sec. The highest tidal water level is 1.21 m with a flow discharge of 978.79 m3/s while the lowest low tide water level is 0.33 m with a flow discharge of 234.95 m3/s. This causes water to overflow at the highest tide, thereby submerging the rice fields that are irrigated by the sub-basin and experiencing drought at low tide. To overcome this, a sluice gate is needed in the secondary channel to regulate the entry and exit of water.

Numerical Analysis of Fluid Flow and Heat Transfer Characteristics of Novel Microchannel Heat Sink

Microchannel heat sinks have gained prominence in the field of thermal management, offering compact and efficient solutions for dissipating heat flux from high performance electronic devices. Escalating heat flux in modern electronic devices, such as those found in telecommunication equipment, industrial automation equipment, solar devices, and data centre servers has driven the continuous development of microchannel heat sink to achieve efficient thermal management. The critical challenge in thermal management for these devices is to develop a microchannel that enhances heat transfer performance and minimises pressure drop. Heat transfer and pressure drop are two competing factors that determine the practicability of the design for real world application. Improvement in heat transfer performance usually results in an increase in pressure drop and pumping power. This study addresses the challenges of designing microchannel through comprehensive numerical analysis of fluid flow and heat transfer characteristics of a novel design that combines ribs, secondary channels, and tertiary channels. The numerical results showed that the novel microchannel design achieves a favourable balance between heat transfer and pressure drop, demonstrating its potential to be used in application where high heat transfer and efficiency are paramount. To assess the performance of the microchannels, thermal resistance, a measure of system’s resistance to heat transfer is used. At the same pumping power, thermal resistance in the new design is consistently lower compared to other designs.

Characteristics and Management of Drainage Infrastructure in Medan Sunggal District, Medan City

Climate change, characterized by high-intensity rainfall, coupled with inadequate drainage systems, small and shallow river dimensions, and a lack of community awareness, has caused flooding and inundation in Medan Sunggal District. This study aims to understand the characteristics and management of drainage infrastructure in Medan Sunggal Subdistrict, Medan City, to identify its characteristics and implement suitable management efforts. The research adopts a positivism paradigm with a positivistic approach, relying on empirical facts (sensual empiricism). The research methodology used is purely qualitative descriptive, focusing on an in-depth understanding related to the characteristics, context, and research subjects. Data collection methods include Guest Tour and comparative techniques. The results of this study show that the characteristics of drainage infrastructure in the study area form a network pattern. The types of channels in the study area are primary channels, secondary channels, and tertiary channels. They consist of artificial channels with open concrete construction, located above the ground with a combined drainage system. While most of the physical conditions are good, some exhibit minor damage. A significant portion of the drainage water is stagnant. Flood-prone areas constitute 41%, areas with infrequent flooding are at 43%, and areas that have never experienced flooding are at 16%. Management recommendations for the study area include providing green open spaces, creating biopore infiltration holes, constructing detention and retention ponds, using paving blocks/grass blocks, conducting maintenance (normalization and rehabilitation) of drainage, and involving the community in each management aspect.

Perencanaan Drainase di Dusun 1 Penfui Timur

Drainage functions as a series of waterworks that function to reduce or remove excess water from an area or land, so that the land can function optimally. Hamlet 1 is one of the hamlets in East Penfui Village, with an area of 49.47 ha. This hamlet is quite busy with students living because it is located between 2 major campuses in Kupang, namely Nusa Cendana University and Widya Mandira Catholic University Kupang. This hamlet has not been equipped with adequate drainage channels so that during the rainy season there are floods and result in standing water at several points which is quite disturbing to road users and the surrounding community. Therefore, it is necessary to know the magnitude of the planned discharge so that it can determine the dimensions of the channel to overcome the problem of inundation that occurs. From the results of planning the drainage system is divided into 2 primary canals with the notation SP1 and SP2, the P1 channel is 2300 m long and the P2 channel is 600 m long. Calculating the intensity of rainfall using the mononobe formula, with a concentration time of 3.16 hours, the rainfall intensity for the 5 year return period is 30.74 mm. By using the rational method, it is obtained that the planned debit is 2.67 m3/s, in the planning of the drainage system there must be different channel dimensions based on the water discharge flowing through the channel itself. With a planned flood discharge of 24.75 m3/s, the smallest canal has a width dimension of 0.4 m and a height of 0.8 m on the secondary channel while the largest is 0.6 m wide and 1.2 m high on the primary canal, and Infiltration wells have a diameter of 2 m with a depth of. Provided that Q plan < channel discharge. Drainage planning uses a square-shaped channel with precast concrete materials, namely U-ditch channels and calvert box culverts.

Influence of check dams on water and sediment processes and deposition patterns under simulated rainfall conditions

The Loess Plateau in China has the highest soil erosion and water loss rates in the world. Therefore, check dams, which are more useful engineering measures, have been established to improve soil and water conservation in small watershed. To determine check dam configuration pattern influence on runoff, sediment yield, erosion and deposition pattern in watershed, we conducted a rainfall simulation experiment using the qiao gully small watershed as our normal-scale model. We analysed the runoff and sediment yield characteristics and deposition patterns under four types of check dam configurations: no dams constructed, dam in first order stream channel, dam in second order stream channel, and dams in both channels. Our findings revealed that the runoff and sediment concentrations increased with time, regardless of check dam configuration. The significant effects of check dams on the evolution of storm runoff processes in a small watershed. Compared to no dams, double dams best inhibited runoff reduction and lowered sediment deposition, while construction of one dam in the primary channel was more effective than one dam in the secondary channel. In summary, check dam construction reduced channel erosion, rill erosion, and bank slope collapse at the channel head, while raising the dam-controlled watershed base level. Our findings provide a reference for designing check dams in optimal configurations on plateaus such as the Loess Plateau. The results of this study are of great practical significance in revealing the process of storm runoff and identifying key parts of soil erosion–deposition in the watershed.

Numerical and experimental investigation of the deviation of microparticles inside the microchannel using the vortices caused by the ICEK phenomenon.

One field of study in microfluidics is the control, trapping, and separation of microparticles suspended in fluid. Some of its applications are related to cell handling, virus detection, and so on. One of the new methods in this field is using ICEK phenomena and dielectrophoresis forces. In the present study, considering the ICEK phenomena, the microparticles inside the fluid are deviated in the desired ratio using a novel ICEK microchip. The deviation is such that after the microparticles reach the floating electrode, they are trapped in the ICEK flow vortex and deviated through a secondary channel that was placed crosswise and noncoplanar above the main channel. For simulation verification, an experimental test is done. The method used for making two noncoplanar channels and separating the particles in the desired ratio with a simple ICEK microchip is an innovation of the present study. Moreover, the adjustment of the percentage of separation of microparticles by adjusting the parameters of the applied voltage and fluid inlet velocity is one of the other innovations of the present experimental study. We observed that for input velocities of 150-1200 µm/s with applied voltages of 10-33 V, 100% of the particles can be directed toward the secondary-channel.

A Ship Fire Monitoring and Alarm System Based on A Distributed Configuration

This article conducts innovative research based on distributed fire monitoring and alarm systems. It consistst of six FDS Control Panels, connected by a redundant Ethernet network, to ensure that all the FDS Control Panels can receive and transmit the relevant data. This connection is provided with redundant backup using a secondary channel of communication for use when the main channel is not working due to failure or cable damage.

New Mechanistic Insights into the Primary Thermolysis Reactions of 1,3,4,6-Tetranitrooctahydroimidazo-[4,5-d]imidazole (BCHMX) from Predictive Local Coupled Cluster Calculations.

Theoretical studies of the decomposition mechanism of energetic materials quite often scrutinize only the primary thermolysis reactions. However, the secondary reactions are crucial, inter alia, for proper building of the combustion models and understanding the autocatalytic processes. In the present study, we applied predictive DLPNO-CCSD(T) calculations to elucidate the kinetics and decomposition mechanism of a novel promising energetic material, 1,3,4,6-tetranitrooctahydroimidazo [4,5-d] imidazole (BCHMX). We identified eight previously unknown BCHMX conformers, both cis and trans in accordance to the spatial position of the H atoms bonded to a carbon bridge. Among them, the relative enthalpies of cis isomers lie in the narrow range ∼10 kJ mol-1 rendering them thermally accessible in the course of decomposition. The radical N-NO2 bond cleavage via one of the novel conformers is the dominant primary decomposition channel of BCHMX with the kinetic parameters Ea = 168.4 kJ mol-1 and log(A, s-1) = 18.5. We also resolved several contradictory assumptions on the mechanism and key intermediates of BCHMX thermolysis. To get a deeper understanding of the decomposition mechanism, we examined a series of unimolecular and bimolecular secondary channels of BCHMX. Among the former reactions, the C-C bond unzipping followed by another radical elimination of a nitro group is the most energetically favorable pathway with an activation barrier ∼113 kJ mol-1. However, contrary to the literature assumptions, the bimolecular H atom abstraction from a pristine BCHMX molecule by a primary nitramine radical product, not the nitro one, followed by another NO2 radical elimination, is the most important bimolecular secondary thermolysis reaction of BCHMX at lower temperatures. The isokinetic temperature of the bimolecular and unimolecular secondary reactions is ∼620 K. Unimolecular reactions might be important in dilute solutions, where bimolecular reactions are suppressed. The secondary reactions considered in the present work might be pertinent in the case of related energetic nitramines (e.g., RDX, HMX, and CL-20).

Evolution characteristics of pore structure of coal under freeze-thaw cycles combined with scanning electron microscope instrument and nitrogen adsorption experiment

ABSTRACT In this paper, anthracite in Shanxi region is taken as a research object, and the pore structure of coal under different freeze-thaw times is characterized and analyzed by scanning electron microscope and nitrogen adsorption experiment. The SEM experimental results show that the micron-scale cracks on the surface of anthracite gradually connect after freeze-thaw, and the secondary crack channels are formed around the pores and air holes, so that the pores also begin to connect. Further, the quantitative information of the picture was extracted, and it was found that the surface porosity and fractal dimension of the coal sample changed significantly after three freeze-thaw cycles, which increased by 163.3% and 15.9% respectively, and increased with the increase of freeze-thaw cycles. The results of low-temperature nitrogen adsorption experiments show that the coal samples after freeze-thaw are mainly crack, and the pore structure changes from simple to complex. In addition, the maximum nitrogen adsorption capacity, specific surface area and pore volume increased by 125.7%, 69.3% and 72.6%, respectively. With the increase of freeze-thaw times, the growth rates of maximum nitrogen adsorption capacity, specific surface area and pore volume are significantly different. The results of joint characterization show that the number of pores and cracks increases to different degrees after freezing and thawing. Comparing the increase in the degree of fracturing (163.3%) with the increase in the total pore volume (30.68%), we find that the degree of change of the crack after thawing is higher than that of the pore. In this paper, the damage effect of coal samples after freezing and thawing with liquid nitrogen is investigated from an experimental point of view, which accelerates the great leap of cyclic cryogenic fracturing technology from basic theory to technical practice.

Arctic Permafrost Thawing Enhances Sulfide Oxidation

AbstractPermafrost degradation is altering biogeochemical processes throughout the Arctic. Thaw‐induced changes in organic matter transformations and mineral weathering reactions are impacting fluxes of inorganic carbon (IC) and alkalinity (ALK) in Arctic rivers. However, the net impact of these changing fluxes on the concentration of carbon dioxide in the atmosphere (pCO2) is relatively unconstrained. Resolving this uncertainty is important as thaw‐driven changes in the fluxes of IC and ALK could produce feedbacks in the global carbon cycle. Enhanced production of sulfuric acid through sulfide oxidation is particularly poorly quantified despite its potential to remove ALK from the ocean‐atmosphere system and increase pCO2, producing a positive feedback leading to more warming and permafrost degradation. In this work, we quantified weathering in the Koyukuk River, a major tributary of the Yukon River draining discontinuous permafrost in central Alaska, based on water and sediment samples collected near the village of Huslia in summer 2018. Using measurements of major ion abundances and sulfate () sulfur (34S/32S) and oxygen (18O/16O) isotope ratios, we employed the MEANDIR inversion model to quantify the relative importance of a suite of weathering processes and their net impact on pCO2. Calculations found that approximately 80% of in mainstem samples derived from sulfide oxidation with the remainder from evaporite dissolution. Moreover, 34S/32S ratios, 13C/12C ratios of dissolved IC, and sulfur X‐ray absorption spectra of mainstem, secondary channel, and floodplain pore fluid and sediment samples revealed modest degrees of microbial sulfate reduction within the floodplain. Weathering fluxes of ALK and IC result in lower values of pCO2 over timescales shorter than carbonate compensation (∼104 yr) and, for mainstem samples, higher values of pCO2 over timescales longer than carbonate compensation but shorter than the residence time of marine (∼107 yr). Furthermore, the absolute concentrations of and Mg2+ in the Koyukuk River, as well as the ratios of and Mg2+ to other dissolved weathering products, have increased over the past 50 years. Through analogy to similar trends in the Yukon River, we interpret these changes as reflecting enhanced sulfide oxidation due to ongoing exposure of previously frozen sediment and changes in the contributions of shallow and deep flow paths to the active channel. Overall, these findings confirm that sulfide oxidation is a substantial outcome of permafrost degradation and that the sulfur cycle responds to permafrost thaw with a timescale‐dependent feedback on warming.

Study on the cooling performance of a new secondary flow serpentine liquid cooling plate used for lithium battery thermal management

To improve the thermal and economic performance of liquid cooling plate for lithium battery module in the distributed energy storage systems, on the basis of the traditional serpentine liquid cooling plate, the unidirectional secondary channels and grooves are added, combined to three kinds of serpentine cold plates for the battery module. By contrast, the cold plate with both elliptical groove and secondary channel has the best comprehensive performance. Though the thermal performance is slightly reduced, the consumption of pump power is reduced by 92.6 % and the cooling efficiency coefficient is improved by 12.32 times compared to the original cold plate. The cooling temperature targets of the battery pack are that Tmax less than 40℃ and ΔTavg less than 3 K. In order to achieving the best performance of the cold plate, the influence of the structural parameters and hydrodynamic parameters on the performance index is analyzed, and the sensitivity analysis is carried out which clear the operational mechanism and key design parameters of the cold plate. The results show that different design parameters would generate the change of eddy current which is influential to the cooling performance. Besides, v and D have a significant effect on the performance of the cold plate, followed by d and n, and a has almost no effect on the cooling performance.

Hydrological heterogeneity and the plant colonization of recently deglaciated terrain

ABSTRACT Climate change accelerates glacier retreat, leading to extensive exposure of sediment to light and ecological succession. Succession has traditionally been studied as a chronosequence, where vegetation development is directly correlated with time since glacier retreat or distance from the retreating glacier margin. More recent work has challenged this model, arguing that succession seems to be mainly influenced by heterogeneous conditions at the local scale. The aim of this study was to identify the factors influencing the local-scale establishment of plant communities following glacier recession. Vascular plants and their cover were inventoried in 100 plots (1 m2) for a thirty-year-old alluvial plain in front of the Otemma glacier (Swiss Alps). Depth to water table, distance to the glacial main river and to the nearest channel, sediment size, moss, lichen, and biological soil crust cover were measured. Results showed that proglacial margins develop hydrological heterogeneity over a small scale, reflected in the four observed plant communities. These range from the dry Sempervivum-dominated community, on gravel-rich sediments with a deep water table, to the Trifolium-dominated community, close to secondary channels, with the highest plant cover and species richness and incorporating grassland species. Heterogeneity in water availability exerted a critical control on vegetation development.

How multiple anthropic pressures may lead to unplanned channel patterns: Insights from the evolutionary trajectory of the Po River (Italy)

The aim of this work is to investigate how a sequence of anthropic pressures that occurred on a river sector can generate mutual feedback that determines unplanned channel configurations. We reconstructed the evolutionary trajectory and historical human impacts on a sector of the Po River (Italy). A training scheme was implemented from the 1930 s to the 1950 s along a multi-thread sector of the river to ensure its navigability by bent navigation structures. Other human activities were carried out from the 1960 s to the 1970 s for the exploitation of sediment and water resources, inducing a dramatic reduction in sediment availability along the Po River. Our results show an evolution from multi-thread configurations in the 1950 s to single-thread configurations at the beginning of the 21th century, accompanied by remarkable channel narrowing (-50 %). This evolution has been interpreted as follows: Riverbed lowering occurred exclusively in the main channel during the 1970 s, and the training works enhanced the disconnection and deactivation of the secondary channels that were located behind navigation structures. This localised incision of the active channel (-4 m) was determined by the sediment starvation. In the absence of navigation structures, it is likely that the channel adjustments would have been less profound. The current single thread sinuous pattern is the result of these two anthropic pressures, with the training works defined as an anthropic predisposing condition and the sediment starvation recognised as the triggering factor generating morphological modifications. The channel rearrangement that resulted from these processes can accordingly be defined as unplanned, that is, not designed but caused by diachronous impacts acting on the same river sector for different purposes. The lesson learned from the Po River suggests that anthropogenic, unplanned channel configurations can represent a common type of riverscape in densely inhabited areas significantly affecting recovery potential and future geomorphological trajectories.

Multicoloured Jacquard Artworks Reproduction with C, M, Y, and K Channels Modification to Improve Weave Colour Accuracy

Multi-coloured Jacquard artwork reproduction has been restricted by the modern setting of weaving machinery. To resolve the current limitations, innovative weaving applications have been introduced. The subtractive CMYK system used for colour printing has been employed for multi weave colour reproduction as a wide scope of a weave colour creation is possible by utilizing a small number of weft yarn colours. In use of cyan [C], magenta [M] and yellow [Y] coloured yarns, a range of CMYK secondary colours (red [R], green [G] and blue [B]) production is feasible by juxtaposing a pair of the three yarn colours. In addition, controlling chroma levels of the primary colours is viable by mixing with a black yarn. However, there are variations between CMYK colour mixing and optical yarn colour mixing due to the material differences. Therefore, modifications of the [C], [M], and [Y] colour channels are required to reproduce tertiary colours such as a black colour. This is because opaque and non-blendable yarns are used to create weave colours and therefore, exhibited yarn colours are all perceived together. In use of image processing tools offered by Adobe Photoshop, a pair of the [C], [M], [Y], and [K] colour channels are merged to individually generate the primary ([C], [M], [Y]) and secondary ([R], [G] and [B]) colour channels. In the process, a pair of C, M, Y and K channels is combined based on mathematical functions. As a result, new six colour channels ([C], [M], [Y], [R], [G], and [B]) are created to improve weave colour reproduction accuracy. This study introduces details of the colours segmentation processes and weaving experiment results that examines the significance of the newly developed the colour channels for multi-coloured artwork reproduction.