Usable Levels Research Articles

MemFHE: End-to-end Computing with Fully Homomorphic Encryption in Memory

The increasing amount of data and the growing complexity of problems have resulted in an ever-growing reliance on cloud computing. However, many applications, most notably in healthcare, finance, or defense, demand security and privacy, which today’s solutions cannot fully address. Fully homomorphic encryption (FHE) elevates the bar of today’s solutions by adding confidentiality of data during processing. It allows computation on fully encrypted data without the need for decryption, thus fully preserving privacy. To enable processing encrypted data at usable levels of classic security, e.g., 128-bit, the encryption procedure introduces noticeable data size expansion—the ciphertext is much bigger than the native aggregate of native data types. In this article, we present MemFHE, which is the first accelerator of both client and server for the latest Ring-GSW (Gentry et al. [ 17 ])-based homomorphic encryption schemes using Processing in Memory (PIM). PIM alleviates the data movement issues with large FHE encrypted data while providing in situ execution and extensive parallelism needed for FHE’s polynomial operations. While the client-PIM can homomorphically encrypt and decrypt data, the server-PIM can process homomorphically encrypted data without decryption. MemFHE’s server-PIM is pipelined and is designed to provide flexible bootstrapping, allowing two encryption techniques and various FHE security levels based on the application requirements. We evaluate MemFHE for various security levels and compare it with state-of-the-art CPU implementations for Ring-GSW-based FHE. MemFHE is up to 20 k × (265×) faster than CPU (GPU) for FHE arithmetic operations and provides on average 2,007× higher throughput than [ 36 ] while implementing neural networks with FHE.

High-Gain Multiport DC-DC Converter Topologies for Renewable Energy Applications: A Comprehensive Review

Renewable energy sources have emerged as favorable alternatives for meeting ever-increasing global energy demand. To harness the maximum efficiency from renewable sources, dc-dc converters play a crucial role. While the design of dc-dc converters varies depending on specific application, certain features such as multiport capability and high gain are generally desirable. Multiport structures offer advantages such as compactness and cost reduction, allowing for the efficient integration of various energy sources, storage units, and loads. On the other hand, high gain characteristics enable the step-up of output voltages from renewable energy sources to usable levels. In recent years, numerous converter topologies proposed to address these requirements and enhance overall system performance. This study aims to assist and provide guidance to researchers in the field by reviewing and comparing the most recent advancements in the design and implementation of multiport high-gain dc-dc converters for renewable energy applications. Through a comprehensive analysis of the existing literature, the primary objective of this study is to facilitate knowledge transfer, identify research gaps, and inspire future research endeavors in this domain. By synthesizing the knowledge gained from these studies, researchers can contribute to ongoing advancement of multiport converter technology in the context of renewable energy applications.

Acute Kidney Injury Incidence With Bayesian Dosing Software Versus 2-Level First-Order Area Under the Curve-Based Dosing of Vancomycin With Piperacillin-Tazobactam.

Background: Two methods of area under the curve (AUC) dosing are recommended in vancomycin consensus guidelines: first-order calculations utilizing 2 vancomycin concentrations or a Bayesian approach. It is unknown if there is a difference in acute kidney injury (AKI) between the 2 dosing strategies for patients receiving concomitant piperacillin-tazobactam and vancomycin (VPT). Objective: The objective of this study was to compare incidence of AKI in patients being administered VPT with first-order calculations versus model-informed precision dosing (MIPD)/Bayesian dosing. Methods: This was a single-center, retrospective, observational study at a community hospital. Patients who received VPT therapy for at least 48 hours were included. The primary outcome was overall incidence of AKI. Secondary outcomes included percentage target attainment with initial regimen, average serum creatinine increase, time to AKI, usable vancomycin levels, and need for temporary dialysis or intensive care unit admission. Results: There were 100 patients included (50 in the first-order group and 50 in the MIPD/Bayesian group). The overall incidence of AKI was lower in the MIPD/Bayesian group (12% vs 28%, P = 0.046). There was no difference in average serum creatinine increase, time to AKI, need for temporary dialysis, or intensive care unit admission. Patients in the MIPD/Bayesian group had a higher percentage of target attainment (46% vs 18%, P = 0.003) and usable vancomycin levels (98% vs 60%, P < 0.001). Conclusion and Relevance: In patients receiving VPT, model-informed precision dosing with Bayesian modeling resulted in a lower rate of AKI, higher target attainment, and more usable vancomycin levels compared with first-order AUC dosing. The small sample and retrospective nature of this study reinforces the need for additional data.

Ultimate stability of active optical frequency standards

Active optical frequency standards provide interesting alternatives to their passive counterparts. Particularly, such a clock alone continuously generates highly-stable narrow-line laser radiation. Thus a local oscillator is not required to keep the optical phase during a dead time between interrogations as in passive clocks, but only to boost the active clock's low output power to practically usable levels with the current state of technology. Here we investigate the spectral properties and the stability of active clocks, including homogeneous and inhomogeneous broadening effects. We find that for short averaging times the stability is limited by photon shot noise from the limited emitted laser power and at long averaging times by phase diffusion of the laser output. Operational parameters for best long-term stability were identified. Using realistic numbers for an active clock with $^{87}$Sr we find that an optimized stability of $\sigma_y(\tau) \approx 4\times10^{-18}/\sqrt{\tau [\mathrm{s}]}$ is achievable.

Systematic Component Investigation of the Steady-State High-Temperature In-Pile Nuclear Thermal Propulsion Experimental Test Bed

A high-temperature, steady-state, in-pile experiment was developed to simulate prototypical nuclear thermal propulsion conditions. The experimental development of the resistively heated test apparatus involved spatially scaling the device to a larger heated region from a previous smaller out-of-pile prototype. A series of tests and investigations were conducted to replicate the smaller out-of-pile system’s success of achieving 2500 K. However, limitations within the larger assembly were identified; specifically, the heater filament design does not scale well. The larger assembly can reliably generate usable temperature levels from room temperature up to those exceeding 1300 K for hours. It can briefly sustain a usable 1800 K. The larger system is achieving temperatures over 2500 K, but these are localized and unable to be monitored in the current design. The achieved temperature levels remain suitable for testing various components considered for a nuclear thermal rocket. However, due to the limitations of the current heater filament, it is recommended that the apparatus be redesigned to utilize a rigid heating element similar to that used during the Radioisotope Propulsion Technology Program (Project POODLE) in the 1960s.

Physiological and Metabolic Effects of the Inoculation of Arbuscular Mycorrhizal Fungi in Solanum tuberosum Crops under Water Stress.

Solanum tuberosum is one of the most important crops in the world; however, drought has caused significant losses in its production. One solution is the use of arbuscular mycorrhizal fungi (AMF). In this study, the phenolic profiles and antioxidant activity of the leaves of two potato genotypes (VR808 and CB2011-104) were evaluated over time in crops inoculated with two strains of AMF, as well as a consortium, in combination with a commercial fungicide. In addition, three usable humidity levels were established after the beginning of tuberization. The phenolic compounds found during the first sampling time in the VR808 genotype reached a maximum of 3348 mg kg−1, and in the CB2011-104 genotype, they reached a maximum of 2982 mg kg−1. Seven phenolic compounds were detected in the VR808 genotype, and eleven were detected in the CB2011-104 genotype, reaching the highest concentration at the last sampling time. The antioxidant activity in the first sampling was greater than the Trolox equivalent antioxidant capacity (TEAC), and in the third sampling, the cupric reducing antioxidant capacity (CUPRAC) predominated. The association of AMF with the plant by PCA demonstrated that these fungi assist in protecting the plants against water stress, since in the last harvest, the results were favorable with both mycorrhizae.

Spatial Response Identification Enables Robust Experimental Ultrasound Computed Tomography.

Ultrasound computed tomography techniques have the potential to provide clinicians with 3-D, quantitative and high-resolution information of both soft and hard tissues such as the breast or the adult human brain. Their practical application requires accurate modeling of the acquisition setup: the spatial location, orientation, and impulse response (IR) of each ultrasound transducer. However, the existing calibration methods fail to accurately characterize these transducers unless their size can be considered negligible when compared with the dominant wavelength, which reduces signal-to-noise ratios below usable levels in the presence of high-contrast tissues such as the skull. In this article, we introduce a methodology that can simultaneously estimate the location, orientation, and IR of the ultrasound transducers in a single calibration. We do this by extending spatial response identification (SRI), an algorithm that we have recently proposed to estimate transducer IRs. Our proposed methodology replaces the transducers in the acquisition device with a surrogate model whose effective response matches the experimental data by fitting a numerical model of wave propagation. This results in a flexible and robust calibration procedure that can accurately predict the behavior of the ultrasound acquisition device without ever having to know where the real transducers are or their individual IR. Experimental results using a ring acquisition system show that SRI produces calibrations of significantly higher quality than standard methodologies across all transducers, both in transmission and in reception. Experimental full-waveform inversion (FWI) reconstructions of a tissue-mimicking phantom demonstrate that SRI generates more accurate reconstructions than those produced with standard calibration techniques.

Problem chronologii zolnika z grodziska w Chotyńcu i tworzących go poziomów użytkowych w świetle badań nad klasyfikacją i datowaniem szpil

The article presents the partial results of archaeological research carried out on the burgwall zolnik in Chotyniec, site 1. It aims to classify the historical objects discovered in terms of functional qualification – namely, the pins that were found in 2017-2019, and to introduce them into the scientific circulation. This interesting and relatively numerous series of artifacts complements and enriches our knowledge on many aspects of the zolnik’s function, including its chronology and cultural connections. In this sketch, an analysis of the typological and chronological position of the pins was carried out, and on its basis an attempt was made to estimate the dating of the zolnik (the usable levels that form it).

Quantifying suitable dynamic water levels in marsh wetlands based on hydrodynamic modelling

AbstractThe water level of marsh wetlands is a dominant force controlling the wetland ecosystem function, especially for aquatic habitat. For different species, water level requirements vary in time and space, and therefore ensuring suitable water levels in different periods is crucial for the maintenance of biodiversity in marsh wetlands. Based on hydrodynamic modelling and habitat suitability assessment, we determined suitable dynamic water levels considering aquatic habitat service at different periods in marsh wetlands. The two‐dimensional hydrodynamic model was used to simulate the temporal and spatial variation of water level. The habitat suitability for target species at various water levels was evaluated to obtain the fitting curves between Weighted Usable Area (WUA) and water levels. And then suitable water levels throughout the year were proposed according to the fitting curves. Using the Zhalong Wetland (located in northeastern China) as a case study, we confirmed that the proposed MIKE 21 model can successfully be used to simulate the water level process in the wetland. Suitable water levels were identified as being from 143.9–144.2 m for April to May, 144.1–144.3 m for June to September, and 144.3–144.4 m for October to November (before the freezing season). Furthermore, proposed water diversion schemes have been identified which can effectively sustain the proposed dynamic water levels. This study is expected to provide appropriate guidance for the determination of environmental flows and water management strategies in marsh wetlands.

Optimization of the TEGs Configuration (Series/Parallel) in Energy Harvesting Systems with Low-Voltage Thermoelectric Generators Connected to Ultra-Low Voltage DC–DC Converters

Solar radiation and human activity generate ubiquitous temperature gradients that could be harvested by thermoelectric generators (TEGs). However, most of these temperature gradients are in the range of very few degrees and, while TEGs are able to harvest them, the resulting output voltages are extremely small (a few hundreds of mV), and DC–DC converters are necessary to boost them to usable levels. Impedance matching between TEGs and DC–DC converter plays a fundamental role in the energy harvesting efficiency. Therefore, it is essential to determine the output power of the system in different configurations, in order to decide on the optimum TEG connection. Here, we present an electronic circuit to measure the maximum power that can be harvested with low-voltage TEGs connected to a DC–DC converter. The developed circuit is an electronic controlled load that drains the maximum current from the output of the DC–DC converter while maintaining its output voltage at the maximum allowed value. Using a mechanical set-up able to apply precise low temperature gradients between the hot and cold side of the TEGs, experimental data using different configurations of TEGs are obtained. The measured results show that, for ultra-low voltages, the TEG ensemble’s output impedance plays an important role not only in the amount of the energy scavenged, but also in the onset temperature of the energy harvesting.

A PRACTICAL APPROACH FOR TEACHING THE ORGANIC RANKINE CYCLES (ORC) IN AN ADVANCED THERMODYNAMICS COURSE

Higher Education Institutions must consider the most recently developed technologies to increase energy efficiency. A significant share of the heat used in industry is wasted while still being at usable temperature levels and hence a significant energy saving potential is present in this sector. The Organic Rankine Cycle (ORC) is a system that uses low-grade waste or renewable heat to produce electricity and lower grade heat and can be integrated into a variety of applications. In this paper, an introduction to ORCs is presented, and then, a practical example of a laboratory session using an experimental test bench based in this technology in a last year bachelor’s degree course is detailed. A commercial ORC machine was run in the laboratory session, where the students were able to explore its operation through the graphical interface. They applied the main thermodynamic concepts in the interpretation of the behavior and seen the utility of this science in recently developed environmentally friendly technologies. Then, the students simulated a real case based on the valorisation of exhaust gases from an engine installed in a wastewater treatment plant. Students agreed that the combination of both parts in this session is beneficial for their understanding and that ORC machines are a viable solution to control climate change. Keywords:Combined Heat and Power (CHP); Higher Education (HE); applied thermodynamics; laboratory session; experimental setup; real problem solving

Microbial Fuel Cell stack performance enhancement through carbon veil anode modification with activated carbon powder

The chemical energy contained in urine can be efficiently extracted into direct electricity by Microbial Fuel Cell stacks to reach usable power levels for practical implementation and a decentralised power source in remote locations. Herein, a novel type of the anode electrode was developed using powdered activated carbon (PAC) applied onto the carbon fibre scaffold in the ceramic MFC stack to achieve superior electrochemical performance during 500 days of operation. The stack equipped with modified anodes (MF-CV) produced up to 37.9 mW (21.1 W m−3) in comparison to the control (CV) that reached 21.4 mW (11.9 W m−3) showing 77% increase in power production. The novel combination of highly porous activated carbon particles applied onto the conductive network of carbon fibres promoted simultaneously electrocatalytic activity and increased surface area, resulting in excellent power output from the MFC stack as well as higher treatment rate. Considering the low cost and simplicity of the material preparation, as well as the outstanding electrochemical activity during long term operation, the resulting modification provides a promising anode electrocatalyst for high-performance MFC stacks to enhance urine and waste treatment for the purpose of future scale-up and technology implementation as an applied off-grid energy source.

The trial of immobilization amphoteric metals cations in clay-cement hydroisolation barierrs

One of the main problem of degraded post-industrial areas, preventing their introduction into the secondary economic cycle, is pollution of soil and the impact of these pollution on groundwaters. With the new European Union directives, managers are encouraged to find sound solution for these problems. The process of interaction of contaminated areas is complicated, and the transport of pollutants from the danger place to the usable underground aquifers levels passes through a series of stages of varied mileages.The article presents the possibilities of using ground binders to reduce the emission of ions from soil. The tests have shown that in the case of amphoteric metals, it is possible to accumulate almost 100% of the contamination using clay-cement suspensions.

Miniaturized Ceramic-Based Microbial Fuel Cell for Efficient Power Generation From Urine and Stack Development.

One of the challenges in Microbial Fuel Cell (MFC) technology is the improvement of the power output and the lowering of the cost required to scale up the system to reach usable energy levels for real life applications. This can be achieved by stacking multiple MFC units in modules and using cost effective ceramic as a membrane/chassis for the reactor architecture. The main aim of this work is to increase the power output efficiency of the ceramic based MFCs by compacting the design and exploring the ceramic support as the building block for small scale modular multi-unit systems. The comparison of the power output showed that the small reactors outperform the large MFCs by improving the power density reaching up to 20.4 W/m3 (mean value) and 25.7 W/m3 (maximum). This can be related to the increased surface-area-to-volume ratio of the ceramic membrane and a decreased electrode distance. The power performance was also influenced by the type and thickness of the ceramic separator as well as the total surface area of the anode electrode. The study showed that the larger anode electrode area gives an increased power output. The miniaturized design implemented in 560-units MFC stack showed an output up to 245 mW of power and increased power density. Such strategy would allow to utilize the energy locked in urine more efficiently, making MFCs more applicable in industrial and municipal wastewater treatment facilities, and scale-up-ready for real world implementation.

Investigation of post-industrial pollutions’ immobilization in a hydraulic self-solidifying clay-cement binder

Antifiltration barriers are used to secure deep excavations and flood embankments as well as to prevent the penetration of harmful substances into the ground and groundwater, also as part of the environmental protection system of waste landfills and production plants. The barriers are usually formed from a liquid suspension with binding properties which, after being pumped to the destination, passes into a solid with a fixed strength. One of the main problems of degraded post-industrial areas, preventing their introduction into the secondary economic cycle, is pollution of soil and the impact of pollution on groundwater. The interaction process of contaminated sites is complicated and the transport of pollutants from the place of danger to usable aquifers underground levels passes through a series of varied course. The article presents the possibilities of applications ground binder to reduce the emission of pollutant ions from soils in order to develop new mixtures of binders. The carried out research has shown that in the case of highly contaminated soils (eg Glasgow), almost 100% of heavy metals can be accumulated using clay-cement composites, and also significantly reduce the penetration of aromatic and aliphatic hydrocarbons. Some of the aliphatic hydrocarbons that allowed to enter to the penetrating solutions during measurements also did not exceed the standards.

Effect of Drip Irrigation and Complementary Nutrition with Nitrogen on Potato Quality and Yield

A small-plot field experiment started in 2016 studied effect of drip irrigation on potato tuber yield and starch levels in the tubers. Two potato varieties with different vegetation periods (Monika, Jolana) were exposed to four drip irrigation intensity levels. They were non-irrigated controls and irrigated tubers with 60 %, 65 % and 70 % usable soil water capacity levels. The other studied parameter was represented by the effect of nitrogen fertilisation with the nitrogen nutrient added to the irrigation water (fertigation) in the course of the vegetation period in contrast to one-off application of the whole nitrogen dose before the potato planting. All irrigated variants in comparison to the non‑irrigated controls showed 30–60 % yield increase. The effect of fertigation on yields was statistically insignificant. Starch levels in the tubers were mostly affected by the variety. The irrigated variants in comparison to the non-irrigated controls showed higher starch levels in the harvested tubers but the differences were statistically insignificant.

Perspectives on the use of biomaterials to store platelets for transfusion.

Platelets are routinely stored enabling transfusions for a range of conditions. While the current platelet storage bags, composed of either polyvinylchloride or polyolefin, are well-established, the storage of platelets in these bags beyond 7 days reduces platelet viability below clinically usable levels. New materials and coatings that promote platelet respiration while not supporting platelet adhesion or activation have started to emerge, with the potential to enable platelet storage beyond 7 days. This review focuses on the literature describing currently used biomaterials for platelet storage and emerging materials that are showing promise for improving platelet storage.

Scaling-up of a novel, simplified MFC stack based on a self-stratifying urine column.

BackgroundThe microbial fuel cell (MFC) is a technology in which microorganisms employ an electrode (anode) as a solid electron acceptor for anaerobic respiration. This results in direct transformation of chemical energy into electrical energy, which in essence, renders organic wastewater into fuel. Amongst the various types of organic waste, urine is particularly interesting since it is the source of 75 % of the nitrogen present in domestic wastewater despite only accounting for 1 % of the total volume. However, there is a persistent problem for efficient MFC scale-up, since the higher the surface area of electrode to volume ratio, the higher the volumetric power density. Hence, to reach usable power levels for practical applications, a plurality of MFC units could be connected together to produce higher voltage and current outputs; this can be done by combinations of series/parallel connections implemented both horizontally and vertically as a stack. This plurality implies that the units have a simple design for the whole system to be cost-effective. The goal of this work was to address the built configuration of these multiple MFCs into stacks used for treating human urine.ResultsWe report a novel, membraneless stack design using ceramic plates, with fully submerged anodes and partially submerged cathodes in the same urine solution. The cathodes covered the top of each ceramic plate whilst the anodes, were on the lower half of each plate, and this would constitute a module. The MFC elements within each module (anode, ceramic, and cathode) were connected in parallel, and the different modules connected in series. This allowed for the self-stratification of the collective environment (urine column) under the natural activity of the microbial consortia thriving in the system. Two different module sizes were investigated, where one module (or box) had a footprint of 900 mL and a larger module (or box) had a footprint of 5000 mL. This scaling-up increased power but did not negatively affect power density (≈12 W/m3), a factor that has proven to be an obstacle in previous studies.ConclusionThe scaling-up approach, with limited power-density losses, was achieved by maintaining a plurality of microenvironments within the module, and resulted in a simple and robust system fuelled by urine. This scaling-up approach, within the tested range, was successful in converting chemical energy in urine into electricity.

Small Scale Ceramic MFCs for Efficient Energy Harvesting from Wastewater and Full System Development

Observing continuously increasing demand in the world for water and energy, alternative sources are needed to meet the requirement of a growing population. Microbial Fuel Cell (MFC) represents one sustainable technology that directly converts organic biomass in wastewater into electric current, thus it can be a potential alternative source for energy and water clean-up. Microbial Fuel Cells generate electric current as a direct result of microbial metabolism, where the anodic biofilm is the engine of the process cleaning wastewater and converting chemical energy to electrical energy. MFC technology development into commercial applications has been limited by high cost of materials and low efficiency of energy recovered. Therefore, the successful scale-up process should involve material and design optimisation. With this approach in mind, recent advancements bring the technology closer to the real life implementation thanks to using ceramic for MFC architecture [1] and improved design of multiple units in the system [2]. In addition, it results in electrochemically treated waste and usable electricity levels, for example to power indoor lighting [3]. The main aim of this work was to increase the efficiency of the ceramic based MFCs by compacting the design and exploring the ceramic support as the building block for small scale modular multi-unit systems. The improved energy density would then allow to utilise the energy locked in the feedstock (waste) more efficiently, make MFCs more applicable in industrial and municipal wastewater treatment facilities, and scale-up-ready for real world application. Materials and Methods MFCs were made out of small scale terracotta cylinders (70 mm long, 15 mm diameter) tested in triplicate groups assembled with carbon veil fibre used as anode electrodes. The cathode electrode was made of activated carbon and placed against the ceramic separator inside the hollow cathode chamber. The MFCs were compared against large tubular MFCs (100 mm long, 42 mm diameter) with the same anode to cathode ratio (27:1) and operated in laboratory conditions. Results and Discussion Results showed that the small scale MFCs shown improved power density performance in comparison to the large tubular MFCs. The maximum performance achieved during polarization experiment showed that volumetric density of the small scale MFCs was 21 W/m3 while large MFCs only 8.5 W/m3which is suggests 2.5 improvement of small MFCs. Smaller MFC devices can take the advantage of high surface to volume ratio which in this case was calculated as 2.6 for small MFCs and 1 for large MFCs. During electrochemical MFC operation, the production of catholyte on the surface of the cathode electrode was also observed and driven by generated current. The simplicity of the design is allowing to configure any number of units in parallel configuration and use them in any wastewater tank as ”dip and go” system. This includes MFC use in urinal tanks to power devices in remote locations or in large wastewater treatment plants to lower energy cost. This might also help to solve the electricity and sanitation problem in the Developing World. Efficient utilisation and scale-up allows the technology to come out of the laboratory to field trails to become useful to societies and to the environment. Conclusions This approach leads to more efficient utilization of organic compounds in wastewater including urine and the development of the off-the-grid electrochemical system that allows net generation of usable power and wastewater decontamination. Acknowledgements This work has been supported by the UK EPSRC, grant numbers EP/I004653/1 and EP/L002132/1 and Bill & Melinda Gates Foundation, grant no. OPP1094890.

Membrane-Less Microbial Fuel Cell Powering a Smart Phone: A Self-Stratifying Urine Column

The microbial fuel cell (MFC) is a technology in which microorganisms employ an electrode (anode) as a solid electron acceptor for anaerobic respiration. This result in direct transformation of chemical energy into electrical energy, which in turn means that organic wastewater can be used as fuel. Amongst the various organic wastes that are employed as fuel for MFCs, urine is of interest since it represents 75% of the nitrogen present in domestic wastewaters and yet only 1% of the total volume. However, here is a persistent problem for the scaling up of MFCs. The smaller the surface of electrode to volume ratio of an MFC is, the higher its power density is. Hence, to reach usable power levels, a plurality of units needs to be assembled in stack, which implies configuring both the hydraulic circuitry and the serial/parallel electrical connection patterns. Because of this plurality, the units need to have a simple design for the whole system to be cost-effective. The goal of this work is to address how to build these multiple MFCs in stack. We report a novel membrane-less stack design using manifold ceramic plates semi-submerged with anodes and cathodes sharing urine solution. The top half of each plate were semi-submerged were covered in cathodes while the anodes, on the lower half of each plate, were fully submerged. The MFCs in each box were connected in parallel and multiple modules were configured in series and placed. This allowed self-stratification of the collective environment (urine column) under the natural activity of the microbial consortia thriving in the system. For size comparisons, the module footprints were enlarged from 900 mL to 5000 mL and, importantly, this scaling-up did not negatively affect power density (» 19 W/m^3), a factor that has proven an obstacle in previous studies. However, we should note that this observation is limited for the dimensions we tested. This was achieved by maintaining a plurality of microenvironments within the collective system and resulted in a simple, robust system fuelled by urine. The developed system was then used to treat urine of single individual (» 2.5L per 24h), in order to serve as the energy source charging mobile phones. Six boxes, each comprising 20 MFCs connected in parallel, were hydraulically cascaded and connected in series. Best performances were obtained in pulse-feed batch mode. At equilibrium, the stack of six boxes was feed with 600 mL every 6h at a flow rate of 2 L/min and was producing between 110 and 125 mW. Under these conditions, a smart phone (Samsung Galaxy S, battery of 1600 mAh) was fully charged in 68 h and 80 h, when turned off or on respectively. It has to be noted that these performances were stable for a period of 8 months. We concluded that our scaling-up approach within the tested range was successful to convert chemical energy in urine to electricity and this was demonstrated by charging cell phones.