High Input Load Research Articles

The potential of large floodplains to remove nitrate in river basins – The Danube case

Floodplains remove nitrate from rivers through denitrification and thus improve water quality. The Danube River Basin (DRB) has been affected by elevated nitrate concentrations and a massive loss of intact floodplains and the ecosystem services they provide. Restoration measures intend to secure and improve these valuable ecosystem services, including nitrate removal. Our study provides the first large-scale estimate of the function of large active floodplains in the DRB to remove riverine nitrate and assesses the contribution of reconnection measures. We applied a nutrient emission model in 6 river systems and coupled it with denitrification and flooding models which we adapted to floodplains. The floodplains have the capacity to eliminate about 33,200 t nitrate-N annually, which corresponds to 6.5 % of the total nitrogen emissions in the DRB. More nitrate is removed in-stream at regular flow conditions than in floodplain soils during floods. However, increasing frequently inundated floodplain areas reveals greater potential for improvement than increasing the channel network. In total, we estimate that 14.5 % more nitrate can be removed in reconnected floodplains. The largest share of nitrogen emissions is retained in the Yantra and Tisza floodplains, where reconnections are expected to have the greatest impact on water quality. In absolute numbers, the floodplains of the lower Danube convert the greatest quantities of nitrate, driven by the high input loads. These estimates are subject to uncertainties due to the heterogeneity of the available input data. Still, our results are within the range of similar studies. Reconnections of large floodplains in the DRB can, thus, make a distinct contribution to improving water quality. A better representation of the spatial configuration of water quality functions and the effect of floodplain reconnections may support the strategic planning of such to achieve multiple benefits and environmental targets.

Towards indicators of sustainable development for soybeans productive units: a multicriteria perspective for the Ecuadorian coast

The challenges of food security rely on highly technical productive systems. Monocultures, on the other hand, are reliant on a high input load, negatively impact soil conservation, affecting edaphic biota and generating biological degradation. The study aimed to evaluate the sustainability of Agricultural Productive Units (APU) dedicated to soybean cultivation in Los Rios province, Ecuador, and compare these results with benefits from Ecosystem Services calculated with a geographic information system (GIS) protocol. Through surveys, social, economic and ecological dimensions were evaluated via a multicriteria model. In addition, macrofauna and soil physicochemical conditions were analyzed. As a result, we obtained that 100% of the APU had an Economic Indicator (KI > 2), 65% a Socio-cultural Indicator (SCI > 2) and 99% an Ecological Indicator (EI > 2). Also, there was a suitable agreement between calculated benefits of Ecosystem Services (CBESs) and economic (KI), socio-cultural (SCI), ecological (EI) and general sustainability (GSI) indices. This study intends to make a contribution to the model coupling efforts targeting at exploring the interaction between available farmer information and ES. The dependence on external inputs is established as a critical point, which could constitute a threat to the sustainability of the production system, these findings can play an important role in a decision-making process.

The relationship between total suspended matter and sea current for the spread of Chlorophyll-a and fishing area in Jakarta Bay

Jakarta bay is a water with high input load due to activities from the surrounding river estuaries comes from Jabodetabek regions. This activity impacts the availability of Total Suspended Matter (TSM) in Jakarta Bay. The problem comes when the concentration of TSM exceeds the carrying capacity of the water thus encouraging plankton to grow and breed rapidly which has caused eutrophication. This research has three objectives: (1) Analyzing the relationship of TSM and Chlorophyll-a Case 2 (CHL2), (2) Analyzing impacts between sea current with CHL2 distribution, and (3) Analyzing correlation CHL2 distribution with fish catch data. Data collection was conducted on January 2018 until December 2018. Monthly TSM and CHL2 data were obtained through GlobColour data, monthly data on sea currents were obtained through Marine Copernicus data. TSM and CHL2 data were processed using the GIS and time series method to determine distribution area. Furthermore, a regression analysis is used to determine the relationship of TSM and CHL2. The result: Relationship of TSM and CHL2 obtained R = 0,8508 so that there is a strong association between TSM and CHL2; the current pattern in the Jakarta bay strongly affected by monsoon wind, the highest distribution occurs in the NWM, evenly distribution occurs in the transition 1, and SEM, the lowest distribution occurs in the transition 2; the demersal and pelagic fish catch period occurs in the end of transition 2 period where high CHL2 concentration and low sea current velocity make it easier for fishermen to catch the fish.

FLC and PWM SMC for KY Boost Converter

This paper presents a design and implementation of fuzzy logic controller (FLC) plus PWM sliding mode controller (SMC) for 2nd order-d KY positive output voltage boost converter (KYPOVBC) operated in continuous inductor current mode (CICM). It is more suitable for steady power source in liquid crystal display (LCD), I-pad, CCTV camera, computer parts, light emitting diode (LED), renewable energy and industrial application. The 2nd order-d KYPOVBC always works in CICM and replica of synchronous rectification characteristics. The ON/OFF nature of the 2nd order-d KYPOVBC is nonlinear and their dynamic performance becomes poor. The classical linear controllers are noncapable of output voltage regulation of this converter during the high input supply voltage and load disparities. With the purpose of improving dynamic performance, an output voltage and inductor current regulation of the 2nd order-d KYPOVBC, a SMC plus FLC is designed. The state-space equations of the 2nd order-d KYPOVBC are arrived and then, SMC parameters are calculated. The FLC rules are framed according to the working nature of the 2nd order-d KYPOVBC without mathematical modeling, which is one of the major advantages of the FLC. The SMC acts as an inside loop of this converter to regulate the inductor current, whereas the FLC and proportional integral (PI) controllers act as an outside loop of the same converter for controlling the output voltage. The performance of the designed model is investigated at various operating regions by developing both the experimental and matrix laboratory (MATLAB)/simulation link (Simulink) models in comparison with the SMC plus PI controller. The results are presented to show the best performance of the designed model.

Understanding Dephosphorization in Basic Oxygen Furnaces (BOFs) Using Data Driven Modeling Techniques

Owing to the continuous deterioration in the quality of iron ore and scrap, there is an increasing focus on improving the Basic Oxygen Furnace (BOF) process to utilize lower grade input materials. The present paper discusses dephosphorization in BOF steelmaking from a data science perspective, which thus enables steelmakers to produce medium and low phosphorus steel grades. In the present study, data from two steel mills (Plant I and Plant II) were collected and various statistical methods were employed to analyze the data. While most operators in steel plants use spreadsheet-based techniques and linear regression to analyze data, this paper discusses on the suitability of selecting various statistical methods, and benchmarking tests to analyze such dephosphorization data sets. The data contains a wide range of operating conditions, both low and high phosphorus input loads, different slag basicity’s, different slag chemistries, and different end point temperatures, etc. The predicted phosphorus partition from various statistical models is compared against plant data and verified against previously published research.

PODCA: A Passive Optical Data Center Network Architecture

Optical interconnects have gained great attention recently as a promising solution offering high throughput, low latency, scalability, and reduced energy consumption compared to electrical interconnects. However, some active optical components, such as tunable wavelength converters and micro-electro-mechanical systems (MEMS) switches, suffer from high cost or slow reconfiguration times, and have been roadblocks to the realization of all-optical interconnects. In this paper, we propose three versions of a passive optical data center network architecture (PODCA), depending on the size of the network. Our key device is the arrayed waveguide grating router (AWGR), a passive device that can achieve contention resolution in the wavelength domain. In our architectures, optical signals are transmitted from fast tunable transmitters; pass through couplers, AWGRs, and demultiplexers; and are received by wide-band receivers. Our architecture can scale to over 2 million servers. Simulation results indicate that PODCA exhibits lower latency and higher throughput even at high-input loads compared with electrical data center networks such as Fat-Tree and Flattened Butterfly, and comparable performance with other optical interconnects such as DOS and Petabit, but at much lower cost and power consumption. The packet latency of PODCA in our simulation experiments is below 19 μs, and the throughput is 100%. Furthermore, we compare the power consumption and capital expenditure (CapEx) cost of PODCA with the other four architectures. Results show that PODCA can save at least 75% on power consumption and 50% on CapEx.

Hybrid soft switching converter for DC grid applications

A new soft switched DC/DC converter with low circulating current loss in primary side and low voltage stress in secondary side is presented in direct current micro-grid applications. Modular full-bridge circuits with primary-series and secondary-parallel are used in the studied converter for high input voltage and load current applications. Therefore, the voltage stress of active switches in primary side and the current stress of rectifier diodes in secondary side are reduced. Thus, the low voltage rating switches are utilized to reduce the conduction loss. The input split voltages are balanced using flying capacitors connected between each circuit modular without the complexity control scheme. Phase-shift control is used to regulate the output voltage. Resonant circuit is connected to lagging-leg switches of full-bridge circuit in order to achieve soft switching at light load. The output voltage of resonant converter is connected to the secondary side in order to reset the primary current and clamp the voltage spike across the rectifier diodes at freewheeling state so that the circulating loss is improved. A laboratory prototype with 1.8kW rated power is constructed and tested to verify the theoretical analysis.

A Digitally Controlled Critical Mode Boost Power Factor Corrector With Optimized Additional On Time and Reduced Circulating Losses

In many low-to-mid power applications, critical mode boost power factor corrector converters are widely used because of its low switching loss and simple control. However, near the zero crossing of the input line voltage, an input current distortion and a low power factor are caused by delayed switching period and negative input currents. Generally, an additional on-time method according to the input voltage is used to compensate the input current distortion. However, a detailed quantitative analysis for the exact additional on time has not been studied till now. In this paper, the explicit form of the optimized additional on time has been obtained using a quantitative analysis and the advantage of the digital control. From a state trajectory and “net input charge” analysis, it is shown that the optimized on time should be related to not only the input voltage, but also the output power. Also, in order to improve the efficiency in a high input and light load condition, circulating currents are reduced in the inevitable dead angle with a gate turning-off technique. By using digital control, the optimized additional on time and the gate turn-off technique have been implemented with the 90–230 Vrms input and 380 V/200 W output prototype.

Evaluation of energy and buffer aware application mapping for networks-on-chip

Networks-on-Chip (NoC) is a communication paradigm for Systems-on-Chip (SoC). NoC design flow contains many problems, one of which is called as application mapping problem, which is generally solved in the literature by considering minimization of the communication energy consumption only. Energy and Buffer Aware Application Mapping (EBAM) is a recently proposed method, which handles the application mapping issue as a joint optimization problem for minimizing the energy consumption and buffer utilization simultaneously. EBAM avoids possible high input loads on router buffers at the early mapping stage by using a priori traffic characteristics of the application. Self similarity is already an accepted model in local and wide area networks and many on-chip applications have also been proven to have self similar characteristics. EBAM therefore employs self similar traffic in its joint optimization process and a genetic algorithm is already proposed for its solution.This paper presents a simulation study that evaluates EBAM in terms of network parameters such as buffer utilization and end-to-end delay. For this, a self-similar traffic generator module is implemented first on a well known NoC simulator and then buffer utilization of routers and end-to-end delay under self similar traffic are observed. Simulation results show that the method enhances buffer utilization and end-to-end delay against a reasonable energy trade off.A routing protocol selection task follows the mapping stage in a typical NoC design flow hence our paper also presents a computational study that evaluates the effect of EBAM use on commonly encountered on-chip routing algorithms. Results reveal that simple XY routing protocol, compared to others, performs better on mappings obtained by EBAM, which indicates that the need for complicated routing protocols may be eliminated.

A scalable silicon photonic chip-scale optical switch for high performance computing systems

This paper discusses the architecture and provides performance studies of a silicon photonic chip-scale optical switch for scalable interconnect network in high performance computing systems. The proposed switch exploits optical wavelength parallelism and wavelength routing characteristics of an Arrayed Waveguide Grating Router (AWGR) to allow contention resolution in the wavelength domain. Simulation results from a cycle-accurate network simulator indicate that, even with only two transmitter/receiver pairs per node, the switch exhibits lower end-to-end latency and higher throughput at high (>90%) input loads compared with electronic switches. On the device integration level, we propose to integrate all the components (ring modulators, photodetectors and AWGR) on a CMOS-compatible silicon photonic platform to ensure a compact, energy efficient and cost-effective device. We successfully demonstrate proof-of-concept routing functions on an 8 × 8 prototype fabricated using foundry services provided by OpSIS-IME.

Lethal and sublethal effects of cypermethrin to Hypsiboas pulchellus tadpoles

The study of the effects of the insecticide cypermethrin (CY) technical grade and its Sherpa® commercial formulation on Hypsiboas pulchellus tadpoles assessing lethality, behavior, growth, and abnormalities under standardized laboratory conditions is reported. Observed behaviors were identified and categorized by means of a ranking system according to the loss of mobility. Results of acute lethal effects indicate higher potency for Sherpa® at this level of assessment. All effects on behavior showed an increasing degree of injury as insecticide concentration increased. Organisms exposed to technical grade CY showed lower body length with respect to controls from 3.44 µg CY/L to higher concentrations, whereas those exposed to Sherpa® exhibited lower growth from 0.83 µg CY/L. Both forms of the tested insecticide caused abnormalities between 0.34 and 4.18 µg CY/L, but 100% of malformed individuals was detected from 34.4 µg CY/L for those exposed to the technical grade CY, and from 8.36 µg CY/L for those exposed to Sherpa®. This study proposes the use of easily identifiable and distinguishable sublethal end-points. The high input loads of CY in natural environments, the detected concentrations in the field, in addition to the low levels of this insecticide required to induce sublethal effects (which could eventually lead to death), allow for the conclusion that the insecticide is a risk factor for amphibians inhabiting agroecosystems.

The fate of inorganic colloidal particles in Lake Brienz

The fate of colloidal particles in Lake Brienz and its two main tributaries, the Aare and Lutschine Rivers, was studied over a period of more than a year. Lake colloid loads from the unmodified Lutschine fluctuated significantly across seasons. The highest loads are in summer due to glacier melting. Colloid loads from the Aare reflected the seasonal water use by upstream hydropower plants. A significant number of mineral particles, even outside the theoretical non-settling range, remain in suspension in the epilimnion of Lake Brienz in summer because of the mineralogical nature and shape of the particles and the high input loads. Only 1730 of the 16,800 tons of colloidal particles that entered the lake during the period from 1 June 2004 – 31 July 2005 were exported through the lake outlet. The remainder was presumably lost in the lake through coagulation-sedimentation processes. Coagulation properties of non-fractionated colloid samples in quiescent conditions were studied in the laboratory both in the absence and presence of different organic compounds representative of natural organic matter. Lake Brienz colloids coagulate slowly, as expected from particles (mainly phyllosilicates) bearing a net negative surface charge. Slightly higher coagulation rates were recorded in March and April during the spring algal bloom, which suggests that colloid coagulation is enhanced by carbohydrates. This effect was confirmed in laboratory experiments. However, the concentration of natural organic matter in Lake Brienz is so low that it is not having any significant effect on the fate of inorganic colloids.

CROMA – An Enhanced Slotted MAC Protocol for MANETs

TDMA based MAC protocols can provide a very good utilization of the shared radio resources, especially at high input loads, in synchronized mobile ad hoc networks (MANETs). Global positioning systems like GPS or GALLILEO should provide a very good timing accuracy for synchronization of nodes. This paper presents a new medium access protocol for mobile ad hoc networks, called CROMA. CROMA is collision-free and receiver-oriented. It operates in a slotted environment, in a dynamic and distributed way. In this protocol, receivers act as local base stations and can manage one or several communications on a single slot. Thus, sophisticated functions are allowed at higher layers. Moreover, the hidden terminal as well as the exposed terminal problems are handled by CROMA. A theoretical analysis and extensive simulations show that CROMA can reach very high throughputs.

Capillary Pumped-Loop Thermal Performance Improvement with Electrohydrodynamic Technique

The capillary pumped loop (CPL) is a state-of-the-art technology for cooling spacecraft and telecommunication devices. It is a two-phase heat-transport device in which the driving force is provided by the capillary action of the wick material In the evaporator. Compared to the widely used heat pipes, it provides a higher heat-transport capacity, more flexibility of installation, and greater heat-transport distance because of wickless transport lines and the absence of liquid and vapor counterflowing. The major disadvantages of the CPL are long and complicated startup procedures and the possibility of deprime at high heat input and large load variations. This paper investigates the liquid-vapor separation and thermal management with the electrohydrodynamic (EHD) technique for an EHD-assisted CPL using R-134a as the working fluid. An experimental investigation, along with a mechanism analysis, was employed to evaluate the potential of the EHD technique for thermal performance improvement of CPL systems. Experimental results showed that enhancements, up to three times, could be obtained in heat-transfer coefficients by applying an electric field at different heat load levels. The depriming conditions of a capillary pump can also be prevented with the EHD technique.

Constructed wetlands for wastewater treatment in Estonia

In Estonia many natural/semi-natural wetlands have been used for municipal or agricultural wastewater. During the last 6 years twelve constructed wetlands for wastewater purification were established. Budgets of organic matter (BOD), total-N and total-P of three systems (a sand/plant filter with vertical flow, established in 1992, area 90 m2, loading 3.8 g BOD m−2 d−1; a combined overland flow-vertical flow root-zone system on a Phalaris arundinacea-slope, 1989, 2400 m2 ha, 1 g BOD m−2 d−1; an aquatic macrophyte channel (bioditch), 140 m2, 40 g BOD m−2 d−1), located in southern Estonia, are analyzed. Except for nitrogen, the efficiency of the sand/plant filter was found satisfactory: 82%, 36%, and 74% for BOD5, total-N, and total-P, respectively. The poor performance with respect to nitrogen may be caused by weak vegetation. In thePhalaris -system, 65% of organic matter, 67% N, and 80% P was removed. The average output concentrations of this system were always lower than the recommended limits (BOD5 <10 mg l−1, total-N <10 mg l−1, and total-P <2 mg l−1). Due to the high input load, the BOD5, total-N, and total-P values in the outlet of the bioditch were high and extremely variable: 5–100, 6–16, and 1–4 mg l−1, respectively. To guarantee the recommendable output values from the bioditch, either a significant decrease of input load or an enlargement of the area of the wetlands would be needed. All results show that compared to other seasons the winter performance was not reduced.

Constructed wetlands for wastewater treatment in Estonia

In Estonia many natural/semi-natural wetlands have been used for municipal or agricultural wastewater. During the last 6 years twelve constructed wetlands for wastewater purification were established. Budgets of organic matter (BOD). total-N and total-P of three systems (a sand/plant filter with vertical flow, established in 1992, area 90 m2, loading 3.8 g BOD m−2 d−1; a combined overland flow-vertical flow root-zone system on a Phalaris arundinacea-slope, 1989, 2400 m2 ha, 1 g BOD m−2 d−1 ; an aquatic macrophyte channel (bioditch), 140 m2, 40 g BOD m−2 d−1), located in southern Estonia, are analyzed. Except for nitrogen, the efficiency of the sand/plant filter was found satisfactory: 82%, 36%, and 74% for BOD5, total-N, and total-P, respectively. The poor performance with respect to nitrogen may be caused by weak vegetation. In the Phalaris-system, 65% of organic maller, 67% N, and 80% P was removed. The average output concentrations of this system were always lower than the recommended limits (BOD5 <10 mg 1−1, total-N <10 mg 1−1, and total-P <2 mg 1−1). Due to the high input load, the BOD5, total-N, and tota1-P values in the outlet of the bioditch were high and extremely variable: 5–100, 6–16, and 1–4 mg 1−1, respectively. To guarantee the recommendable output values from the bioditch, either a significant decrease of input load or an enlargement of the area of the wetlands would be needed. All results show that compared to other seasons the winter performance was not reduced.