Decrease In Density Research Articles

NEC violation in [formula omitted] gravity in the context of a non-canonical theory via modified Raychaudhuri equation

In this work, we develop the Raychaudhuri equation in f(R̄,T̄) gravity in the setting of a non-canonical theory, namely K-essence theory. We solve the modified Raychaudhuri equation for the additive form of f(R̄,T̄), which is f1(R̄)+f2(T̄). For this solution, we employ two different scale factors to give two types of f(R̄,T̄) solutions. The ongoing debate between Fisher et al. and Harko et al. in 2020 regarding the additive form of f(R̄,T̄) may provide a resolution within the modified f(R̄,T̄) gravity theory. By conducting a viability test and analyzing energy conditions, we have determined that in the first scenario, the null energy condition (NEC) is violated between two regions where the NEC is satisfied. Additionally, we have observed that this violation of the NEC exhibits a symmetric property during the phase transition. These observations indicate that bouncing events may occur as a result of the symmetrical violation of the NEC during the expansion of the universe. Moreover, this model indicates that resonant-type quantum tunneling may take place during the period when the NEC is violated. The findings of NEC violation through the power law of scale factor may have empirical relevance in contemporary observations. In the second scenario, our model indicates that the strong energy condition is violated, but the NEC and weak energy conditions are satisfied. The effective energy density decreases and is positive, while the effective pressure and equation of state parameters are negative. This suggests that the universe is expanding with acceleration and is dominated by dark energy.

Microstructural Evolution of P92 Steel with Different Creep Life Consumptions After Long-Term Service

P92 steel is widely used in ultra-supercritical units due to its excellent high-temperature performance. This paper studies the microstructure of P92 steel steam pipes in three conditions: as-supplied, after 80,000 h of service at 67.06 MPa stress, and after 100,000 h of service at 80.28 MPa stress. After prolonged service, the P92 steel retains its martensitic structure, but the lath width increases and the dislocation density decreases. In addition to M23C6, MX, and Laves phases, Z phase was also observed among the precipitates. The results indicate that the sizes of M23C6 and Laves phases increase with the progression of creep life consumption, with the coarsening rate of Laves phase being significantly higher than that of M23C6. However, the coarsening of MX phase is not evident. Compared to the Laves phase, the formation of the Z phase requires a longer period of time. The precipitation of the Z phase consumes MX carbonitrides, and it has been observed that the Z phase precipitates from the MX phase, with the two phases exhibiting a coexisting state.

Application of lactoferrin for the prevention and restoration of bone tissue in Wistar rats under conditions of hindlimb unloading

The influence of gravitational unloading (antiorthostatic suspension) and subsequent recovery on the mineral density and mechanical properties of the femoral and tibial bones of Wistar rats was studied with oral administration of a biotechnological analog of human lactoferrin (200 mg/kg) derived from the milk of producer goats. Bone mineral density was determined by dual-energy X-ray absorptiometry, and strength and stiffness were assessed through three-point bending tests. It was shown that gravitational unloading for 21 days led to a decrease in the mineral density of the tibial and femoral bones. The administration of lactoferrin did not significantly affect the mineral density or projected area of the studied bones. No statistically significant differences in mechanical stiffness were found between the experimental groups, but after readaptation, the ultimate strength was significantly higher in the groups that received lactoferrin. Thus, the obtained results may indicate the potential of lactoferrin preparations as prophylactic agents for maintaining bone strength. At the same time, maintaining bone mineral density under deficit-stimulating conditions requires consideration of alternative dosages and delivery methods of the drug.

Biomass-Derived-Carbon-Supported Spinel Cobalt Molybdate as High-Efficiency Electrocatalyst for Oxygen Evolution Reaction.

Ananas comosus leaves were converted to a porous graphitized carbon (GPLC) material via a high-temperature pyrolysis method by employing iron salt as a catalyst. A cobalt molybdate (CoMoO4)-and-GPLC composite (CoMoO4/GPLC) was then prepared by engineering CoMoO4 nanorods in situ, grown on GPLC. N2 adsorption-desorption isothermal curves and a pore size distribution curve verify that the proposed composite possesses a porous structure and a large specific surface area, which are favorable for charge and reactant transport and the rapid escape of O2 bubbles. Consequently, the as-synthesized CoMoO4/GPLC shows low overpotentials of 289 mV and 399 mV to afford the current densities of 10 mA cm-2 and 100 mA cm-2 towards the oxygen evolution reaction (OER), which is superior to many CoMoO4-based catalysts in previous studies. In addition, the decrease in current density is particularly small, with a reduction rate of 3.2% after a continuous OER procedure for 30 h, indicating its good stability. The excellent performance of the CoMoO4/GPLC composite proves that the GPLC carrier can obviously impel the catalytic activity of CoMoO4 by improving electrical conductivity, enhancing mass transport and exposing more active sites of the composite. This work provides an effective strategy for the efficient conversion of waste ananas comosus leaves to a biomass-derived-carbon-supported Co-Mo-based OER electrocatalyst with good performance, which may represent a potential approach to the development of new catalysts for OER, as well as the treatment of waste biomass.

Valorization of Different Clays Used in the Treatment of Oily Wastewater in the Development of Construction Products

AbstractThe aim of this research is to study the feasibility of using clays used in the decontamination of wastewater containing olive oil wastewater (OOW), new lubricating oil (NOW) or motor oil (MOW) in the manufacture of ceramic bricks. Three types of clays were used for filtration, kaolinite type clay (KT), smectite type clay (CT) both from Tunisia and illitic chloritic clay (CS) from Jaén (Spain). These clays containing different types of oils, as well as the control clays, were used in the manufacture of bricks fired at 900 °C. These bricks were characterized by physical, mechanical and thermal tests. The sintered microstructure’s evolution was followed by tracked through scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). The results indicate that the specific type of clay used influences the technological characteristics of the bricks. The use of CT clay gives rise to increase bulk density, greater compressive strength, and reduced apparent porosity and water absorption. The use of clays used in the decontamination of water containing oils produced a decrease in bulk density, compressive strength and thermal conductivity and leads to an increase in apparent porosity and water absorption in the order OOW > NOW > MOW according to the total organic carbon content (TOC). Therefore, the use of clays used in the filtration of water that contain different oils can represent a promising way of valorizing this waste, which can alleviate the environmental impact and represents economic savings for the industry of construction materials with properties of thermal insulation, getting closer to a circular economy.

Optimizing energy density in dielectric elastomer generators: a reliability-dependent metric

Abstract Dielectric elastomer generators (DEGs) are soft transducers capable of converting mechanical energy into electrostatic energy. Increasing the mechanical stretch amplitude and the electric field imposed to the DEG leads to higher energy conversion at the cost of a reduced lifetime. Here, mechanical fatigue and electrical degradation were assessed on a silicone-based DEG, and the outcome was used to build an electro-mechanical reliability model. A novel metric, termed levelized energy density, has been introduced to carefully balance the conflicting objectives of high energy output and long-term reliability. Through a multi-dimensional anaylsis of this index, the optimal operating parameters (stretch amplitude and electric field) that maximize energy conversion can be derived. Energy densities reported in literature are generally obtained after pushing the DEG close to their intrinsic limits for a limited number of cycles. In our approach, more realistic values in the endurance domain are presented, which typically leads to a 9-fold decrease in energy density for a design life of 1 million cycles. This article not only addresses the challenge of optimizing DEG performance but also emphasizes the importance of considering realistic operational conditions to enhance reliability, ultimately contributing to the practical and sustainable deployment of these soft transducers in various applications.

Drying Shrinkage Properties and Engineering Performance for Cement Mortar Containing Bamboo Biochar Powder (BCP)

Drying shrinkage, the reduction in volume as a material like cement mortar dries, can result in cracks and decreased durability. Bamboo biochar powder (BCP) serves as a substitute for cement in mortar, affecting its drying shrinkage characteristics. Research has shown that BCP in cement mortar can alleviate drying shrinkage by absorbing and retaining moisture. This study aims to assess the chemical and physical properties of BCP, determine the mechanical attributes of bamboo biochar mortar with varying percentages of cement replacement, and investigate the impact of BCP on mortar shrinkage in indoor and outdoor tropical conditions. BCP, derived from Gigantocholoa Abociliata species and sized at 75 µm, was used to replace cement rates of 0%, 5%, 10%, 15%, and 20%. Sixty cube samples (50x50x50mm) were employed for density, ultrasonic pulse velocity (upv), compressive strength, and water absorption tests. Additionally, thirty prism samples (100x100x400mm) were employed to assess drying shrinkage during outdoor and indoor exposure, spanning up to 150 days. The experimental data indicates a consistent trend as the percentage of cement replacement increases in the mortar mix, density, and compressive strength decrease, while UPV and water absorption increase. The lowest shrinkage strain was observed during indoor exposure with 5% cement replacement, attributed to BCP acting as a filler, creating strong bonding properties, and reducing shrinkage. Conversely, the highest strain was noted during outdoor exposure with 20% cement replacement, resulting from higher moisture loss. In summary, a 5% replacement of cement with BCP in mortar offers the most effective reduction in shrinkage strain.

Experimental Study of Hot-Sphere Anemometer Response in Stratospheric Environment.

Accurate wind speed measurement in low-pressure conditions is crucial for the thermal performance validation and attitude control of stratospheric aircraft. As air density decreases, traditional wind speed measurement systems based on principles such as dynamic pressure, heat transfer, ultrasound, and particle velocimetry face significant challenges when applied in low-pressure environments, often failing to achieve the required measurement accuracy. This paper presents the development of a wind speed simulation system based on a rotation method designed to operate in low-pressure conditions, utilizing a space environment simulation chamber in conjunction with a high-precision turntable. The system was employed to conduct response tests on a constant heat flow thermal sphere anemometer within a stratospheric pressure range of 1 kPa to 30 kPa. The experimental results revealed that at extremely low Reynolds numbers, the probe signal exhibited increasing nonlinearity, significantly affecting the response curve at pressures below 15 kPa. While the sensitivity of the hot-sphere probe remained relatively stable at wind speeds above 5 m/s, it decreased nonlinearly as the pressure dropped when wind speeds fell below 5 m/s. Furthermore, this paper analyzes the impact of various interpolation methods on wind speed conversion errors, providing valuable data to support the future development and validation of stratospheric aircraft.

Polymer Brushes Synthesized by the "Grafting-through" Approach: Characterization and Scaling Analysis.

In this study, a combined morphological and scaling analysis of brushes synthesized by the "grafting-through" method was performed, and the possibility of regulation of the thickness was revealed on an example of polyacrylamide brushes. The chemical composition of the surface in the proposed three-step approach was analyzed by photoelectron and infrared spectroscopy. It was shown that the thickness of the dried brush can be tuned in a controlled manner by varying the polymerization temperature. The scaling dependence of the thickness of the dried brushes d on the length of the polymer d ∼ Lv was obtained by comparing reflectometry and dynamic light scattering data. The value of the exponent v = 0.82 corresponds to a rather high grafting density, exceeding the density of mushroom-like (ν ∼ 1/3) brushes and approaching the value for stretched polymer brushes (ν ∼ 1). A 10-fold increase in the polymer molecular weight leads to a slight decrease in grafting density by a factor of 2, which suggests that the "grafting-through" approach allows obtaining brushes with a high grafting density independently of attached polymer chain length. Herein, the possibility of attachment of uniform polymer brush on large substrates with this approach was demonstrated, which means the scalability of the "grafting-through" technique. The considered approach opens up a simple way for surface modification with polymer nanolayers of controlled thickness.

Numerical simulation of fluid flow characteristics and ultrasonic cavitation performance in novel-designed stirred tank sonoreactor

A novel-designed stirred tank sonoreactor was developed to well solve large-scale dispersion of nanoparticles in liquid phase system. The fluid flow characteristics and ultrasonic cavitation performance in the sonoreactor were numerically simulated by CFD method. By comparing the pressure, cavitation bubble and velocity distribution under different situations, it is found that larger ultrasonic amplitude, relatively smaller ultrasonic frequency, higher saturated vapor pressure and lower viscosity of liquid medium are beneficial to ultrasonic cavitation. Besides, the acoustic flow action is strengthened with the increase of ultrasonic frequency and decrease of gas-liquid mixture's average density. For the designed sonoreactor, it is critical that high-frequency transducers should be determined near the bottom and upper region of the kettle, and large-amplitude transducers can be confirmed in the middle position. The research findings will provide theoretical and technical supports for developing state-of-the-art sonoreactors and optimizing ultrasonic process parameters in the industrialized preparation of nanocomposites.

Synthesis, characterization, and electrical properties of Nd3+‐doped (Bi0.4Na0.2K0.2Ba0.2)TiO3 high‐entropy ceramics

AbstractRecently, high‐entropy perovskites have attracted considerable attention due to their diverse chemical composition and multifunctionality. In this study, the high‐entropy approach was employed in a (Bi0.4Na0.2K0.2Ba0.2)TiO3 matrix, and Nd3+ was introduced to enhance the configurational entropy and modify its dielectric and ferroelectric properties. Notably, despite Nd3+ doping, all samples maintained a tetragonal perovskite structure at room temperature. The configurational entropy increased with the Nd3+ concentration, consequently leading to a gradual decline in the ferroelectric properties along with the associated temperature (Tm) and maximum dielectric constant (εm). The P–E loops of the ceramics also became thinner as Pm and Pr decreased, resulting in a slow decrease in the recoverable energy density (Wrec) and a simultaneous increase in the energy storage efficiency (η). Especially, the energy storage performance reached its peak at an Nd3+ concentration of 12 mol%, exhibiting an energy storage efficiency of 85.8% and a recoverable energy storage density of 0.74 J/cm3 at a low electric field of 100 kV/cm. These results highlight the potential of this material for dielectric applications in low electric fields and contribute to the advancement of alternative high‐entropy energy storage perovskite ceramics.

Effect of germination on the physico-functional and nutritional profile of barnyard millet ()(VL-172)

: Barnyard millet is well-known for its abundant nutrients and adaptability, making it a promising candidate for product innovation, especially by exploring new processing methods like germination to boost its nutritional value and effectiveness. It is vital to examine both the physico-functional and nutrient characteristics of barnyard millet in order to fully harness their nutritional advantages in product development. Understanding factors such as grain size and properties like water and oil absorption capacity is crucial for creating inventive, nutritionally enriched foods that can meet a variety of dietary requirements and gain wider market acceptance.: This scientific approach fosters the effects of germination on the physico-functional and nutritional properties of Barnyard millet. : Barnyard millet was collected and soaked for 12 hours and germinated in different time intervals, then dehydrated at 110°C for 4 hours. Physical properties such as kernel size and volume were analysed. Functional properties, including oil and water absorption capacity, water solubility and nutritional analysis were conducted. The study revealed that as the germination time increased, the length-width ratio increased, accompanied by a slight increase in 1000 kernel weight, volume and decrease in bulk density of germinated millet. Furthermore, functional properties such as oil absorption capacity, water absorption capacity and water solubility index increased with germination time, contributing to improved texture. There was increase in protein and fiber, slight decrease in fat content. The mineral content was increased upon germination. The obtained results indicated slight variations in the physical and functional and nutritional characteristics of barnyard millet and its flour upon germination.

The evolution and dissolution mechanism of θ-Al2Cu phase and the analysis of precipitation of a novel AlCu phase during elevated aging

The evolution and dissolution mechanism of the θ-Al2Cu precipitates were investigated in this study by transmission electron microscopy (TEM) during the re-aging at high temperatures for a long time. The results advance the current knowledge of dissolution and its associated mechanisms of the θ-Al2Cu phase in AlCu alloys. In this study, the coarsening and dissolution of θ-Al2Cu phase in T6 heat-treated Al4Cu alloy during various times (0−1000h) of re-aging temperature 420 °C were studied experimentally and theoretically. The morphological characterization revealed that the θ-Al2Cu phases gradually increase in size and decrease in volume density during the aging process, which can be attributed to coarsening and dissolution phenomena occurring during re-aging. Additionally, a body-centered tetragonal AlCu phase is precipitated within the θ-Al2Cu phase during the high temperature re-aging process, which is a characteristic of this phase prior to dissolution. Moreover, the primary mechanisms responsible for the high temperature melting of the θ-Al2Cu phase are the formation of the AlCu phase and the initial melting of the Cu-poor region in the θ-Al2Cu phase. The Cu atoms in θ-Al2Cu phase dissolve and diffuse into the Al matrix, forming L12 ordered AlCu solute clusters through long-range diffusion.

Correlation of CT measurements of total body gas volume and hounsfield units with post-mortem interval

Accurate estimation of the post-mortem interval (PMI) may be a matter of crucial importance in forensic investigations.A preliminary investigation to assess whether longitudinal changes in organ Hounsfield units (HU) and total body gas volume (TBGV), as measured from serial PMCT scans, correlate with postmortem interval (PMI).: Eight euthanised lambs each had five whole body CT scans performed over seven days and measurements were taken from the brain, heart, lungs, liver, kidneys and spleen. HU tissue density was measured directly from the PMCT images, while TBGV was calculated using ImageJ software. A random effect model was fitted with the subject fitted as a random intercept. Ethical and Animal Welfare approval was obtained. : The average increase in TBGV was 422 ml/Kg with a change of 77 ml/Kg per day. For each additional post-mortem day, the HU of the brain, heart, lung, liver and spleen decreased by per day since death, while HU for the kidneys increased by day since death. Expect for the kidney where it increased, there was clear and progressive decrease in tissue densities and for all organs there was an increase in TBGV over time. However, the overlap in values between cases indicates that more work is required before either HU or TBGV can be developed as non-invasive methods to reliably determine time of death in humans.

OsPDIL1-5: dual role in promoting growth and development while modulating drought stress tolerance in rice (Oryza sativa L.).

Drought tolerance and plant growth are critical factors affecting rice yield, and identifying genes that can enhance these traits is essential for improving crop resilience and productivity. Using a growth-depressed and drought-tolerant (gddt) mutant of the indica rice variety Huanghuazhan (HHZ) generated by radiation mutagenesis, we discovered a novel gene, GDDT, which plays a dual role in plant biology: it acts as a positive regulator of growth and development, but as a negative regulator of drought resistance. The gddt mutant displayed a marked reduction in plant growth and seed setting rate, yet exhibited an unexpected advantage in terms of drought tolerance. Our research revealed that the enhanced drought tolerance of the gddt mutant is primarily due to a decrease in stomatal size, density, and aperture, which reduces water loss, and an activation of the reactive oxygen species (ROS) scavenging system, which helps protect the plant from oxidative stress. These physiological changes are observed both under drought conditions and in normal growth conditions. This discovery highlights the importance of GDDT as a pleiotropic gene with significant implications for both plant growth and drought resistance. Through map-based cloning, we determined that the protein disulfide isomerase-like (PDIL) gene OsPDIL1-5 is the GDDT gene. The protein encoded by this gene was localized to the endoplasmic reticulum, consistent with its predicted function. Our findings provide new insights into the role of PDIL genes in rice and suggest that further study of GDDT could lead to a better understanding of how these genes contribute to the complex interplay between plant growth, development, and stress responses. This knowledge could pave the way for the development of rice varieties that are more resilient to drought, thereby increasing crop yields and ensuring food security in water-limited environments.

Evidence of apoptosis as an early event leading to cyclophosphamide-induced primordial follicle depletion in a prepubertal mouse model.

The mechanisms leading to ovarian primordial follicle depletion following gonadotoxic chemotherapy with cyclophosphamide and other cytotoxic drugs are currently understood through two main explanatory theories: apoptosis and over-activation. Discrepancies between the findings of different studies investigating these mechanisms do not allow to reach a firm conclusion. The heterogeneity of cell types in ovaries and their different degrees of sensitivity to damage, cell-cell interactions, periodical follicle profile differences, model age-dependent differences, and differences of exposure durations of tested drugs may partially explain the discrepancies among studies. This study used intact prepubertal mice ovaries in culture as study model, in which most follicles are primordial follicles. Histological and transcriptional analyses of ovaries exposed to the active metabolite of cyclophosphamide 4-hydroperoxycyclophosphamide (4-HC) were carried out via a time-course experiment at 8, 24, 48, and 72 h. 4-HC treated ovaries showed a significant decrease in primordial follicle density at 24 h, along with active DNA damage (TUNEL) and overexpressed apoptosis signals (cleaved-poly ADP ribose polymerase in immunohistochemistry and western blotting). Meanwhile 4-HC treatment significantly up-regulated H2ax, Casp 6, Casp 8, Noxa, and Bax in ovaries, and up-regulated Puma in primordial follicles (FISH). Our results indicated that cyclophosphamide-induced acute ovarian primordial follicle depletion was mainly related to apoptotic pathways. No evidence of follicle activation was found, neither through changes in the expression of related genes to follicle activation nor in the density of growing follicles. Further validation at protein level in 4-HC-treated prepubertal mice ovaries at 24 h confirmed these observations.

Exploring the wear resistance of EPDM‐PAE/SWCNTs composites with a novel perspective of micro‐network structure

AbstractThe effect of single‐walled carbon nanotubes (SWCNTs) on the crosslinking network structure of Ethylene Propylene Diene Monomers (EPDM)—Polyamide elastomers (PAE) is investigated in detail using Hansen Solubility Parameter (HSP) theory. Rheological method and scanning electron microscopy (SEM) are used to investigate the effect of SWCNTs on the molecular chain movement and their interaction with the filler network of EPDM‐PAE. The DIN abrasion test is conducted to obtain the effect of SWCNTs on the wear characteristics of EPDM‐PAE/SWCNTs composites. The linear synergistic relationship between crosslinking density and wear volume indicates that the change in wear properties is contributed by the micro‐network structure. The addition of SWCNTs increases the chemical crosslinking density and improves the wear properties of EPDM‐PAE. However, the decrease in the physical crosslinking density leads to an increase in the degree of internal friction within the network structure, resulting in a decrease in the wear performance. Changes in wear resistance can be related to the micro‐network structure, which provides a novel approach to studying the wear characteristics of high‐performance elastomers. It is also an innovative work based on the network structure to guide the preparation of new wear‐resistant elastomeric materials.

Understanding the correlation of aging treatments and stress corrosion crack growth of a secondary hardening ultra-high strength steel

The correlation of aging treatments and stress corrosion crack growth of a secondary hardening ultra-high strength steel was investigated using microstructural characterization, electrochemical hydrogen penetration experiment, thermal desorption spectroscopy analysis, and stress corrosion crack growth test. The results showed that increase of aging duration led to slight increase in the fraction of reversed austenite but decrease in dislocation density while no notable variation in grain boundary misorientation distribution and the corrosion behavior was observed. The shrinkage and fracture toughness continued to increase with aging duration while the yield strength reaching a maximum value after 5 hours of aging. Longer aging durations led to the decrease in effective hydrogen diffusion coefficient but improvement of stress corrosion cracking resistance, mainly due to the coarsening and nucleation of M2C carbides, as well as the higher fraction of reversed austenite. This work provided the theoretical and technical basis for improving the stress corrosion cracking resistance of this steel.

Effect of Tempering Temperature on the Aqueous Corrosion Resistance of 9Cr Series Heat-Resistant Steel

In this investigation, the aqueous corrosion resistance of 9Cr series heat-resistant steel during tempering was investigated. Optical Microscopy (OM), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectrometer (EDS) were used to analyze the effect of tempering temperature on the microstructure and precipitation behavior of precipitates. The heat-resisting steel was heated to 1150 °C for 1 h, and then tempered at different temperatures between 680 °C and 760 °C for 2 h. The microstructure of the heat-resistant steel after tempering was composed of lath-tempered martensite and fine precipitates. The hardness decreased with increasing tempering temperature, ranging from HBW 261 to HBW 193. The aqueous corrosion resistance improved as the tempering temperatures increased from 680 °C to 720 °C but deteriorated at higher temperatures, such as 760 °C, which was obtained by an electrochemical corrosion performance test. The aqueous corrosion resistance was affected by the decrease in dislocation density and the decrease in Cr solution in the tempered martensite. With the increase in the tempering temperature, the aqueous corrosion potential first increases and then decreases, the self-corrosion current density first decreases and then increases, and the polarization resistance first increases and then decreases. Furthermore, the increase in corrosion resistance is attributed to the reduction in dislocation density and chromium depletion in the martensitic structure as the tempering temperature approaches 720 °C. This paper reveals the effect of tempering temperature on the corrosion resistance of 9Cr series heat-resistant steel, which is a further exploration of a known phenomenon.

Intact photosynthetic bacteria-based electrodes for self-powered metal ions monitoring

The low-cost and early monitoring of metal ion contaminants is paramount to prevent widespread contamination of water environments. Self-powered microbial electrochemical sensors represent an interesting approach to achieving this goal. Purple non-sulfur bacteria have a versatile metabolism and a well-characterized photosynthetic system, making them an ideal candidate for developing biohybrid technologies. In this work, we report the use of these bacteria in biophotoelectrodes to develop self-powered monitoring systems for two common pollutants, NiCl2 and CuSO4. The microbial biophotoelectrode was obtained on a homemade poly-hydroxybutyrate-carbon nanofibers electrode modified with a redox-adhesive polydopamine matrix-based entrapping the purple bacterium Rhodobacter capsulatus. The presence of 500 μM NiCl2 resulted in a 60 % decrease in current density, while the simultaneous presence of 100 μM NiCl2 and 100 mM CuSO4 led to an 83 % current inhibition. Given the implementation of the biophotoelectrode in the field, the biohybrid system was tested in a complex matrix containing beer, demonstrating the promising ability of the photoelectrochemical system to act as an efficient biosensor in complex solutions. Finally, the biohybrid electrode was coupled to a cathode performing oxygen reduction, which allowed obtaining a self-powered monitoring system, paving the way for the future implementation of a low-cost monitoring system for widespread metal ions contaminant monitoring.