Laboratory Scale Research Articles

Bioplastic’s Valorisation by Anaerobic Co-Digestion with WWTP Mixed Sludge

Bioplastics are designed to degrade at the end of their lifecycle, but effective management of their end-of-life phase and integration into existing organic waste management systems remain significant challenges. Some bioplastics decompose under anaerobic conditions, with the anaerobic digestion (AD) process being a potential solution for their disposal. AD is a promising technology for valorising organic wastes, enabling biomethane production, reducing carbon footprints, and promoting product circularity. This study focuses on evaluating the continuous co-digestion of bioplastics with mixed sludge from an urban wastewater treatment plant (WWTP). Polyhydroxybutyrate (PHB) was the selected bioplastic, as various studies have reported its high and rapid degradation under anaerobic mesophilic conditions. PHB’s biodegradability under typical WWTP anaerobic digestion conditions (35 °C, 20-day retention time) was assessed in batch tests and the results indicate that PHB degradation ranged from 68 to 75%, depending on particle size. To further explore the potential of AD for PHB valorisation, the feasibility of anaerobic co-digestion of PHB with WWTP sludge was tested on a continuous laboratory scale using two digesters: a conventional digester (CSTR) and an anaerobic membrane bioreactor (AnMBR). The results indicated complete degradation of PHB, which led to higher biomethanisation percentages in both digesters, rising from 58% to 70% in the AnMBR and from 44% to 72% in the CSTR. The notable increase observed in the CSTR was attributed to changes in microbial populations that improved sludge biodegradability.

Novel sparging strategies to enhance dissolved carbon dioxide stripping in industrial scale stirred tank reactors

Aerated stirred tank reactors are widely used in bio-process engineering and pharmaceutical industries. To supply the organisms with oxygen and control the pH value, oxygen is transferred from air bubbles into the liquid phase, and, at the same time, carbon dioxide is stripped from the liquid phase with the same gas bubbles. The volumetric mass transfer coefficients for oxygen and carbon dioxide are, therefore, of crucial importance for the design and scale-up of aerated stirred tank reactors. In this experimental work, the volumetric mass transfer coefficients for oxygen and carbon dioxide are investigated simultaneously to study their mutual influence. The mass transfer performance for oxygen and carbon dioxide is conducted in stirred tank reactors on the 3 L laboratory scale, 30 L pilot scale, and 15,000 L production scale. First, the influence of dissolved carbon dioxide on the oxygen mass transfer performance is investigated in a 30 L pilot scale stirred tank reactor. The results show that the volumetric mass transfer coefficient of oxygen is not affected by the concentration of dissolved carbon dioxide, but the total mass flux of oxygen decreases with increasing carbon dioxide concentration due to the decreasing partial pressure difference. With rising gassing rate and volumetric power input, both mass transfer coefficients for oxygen and carbon dioxide show the same increasing trend. Although this trend can also be observed when scaling down to the 3 L laboratory scale reactor, a significantly different effect must be considered for the scale-up to the 15,000 L industrial scale reactor. The limited absorption capacity for carbon dioxide of the gas bubbles during the long residence time in the industrial scale reactor is noticeable here, which is why the specific interfacial area is of negligible importance. This effect is used to develop a method for independent control of oxygen and carbon dioxide mass transfer performance on an industrial scale and to increase the mass transfer performance for carbon dioxide by up to 25%.

Salmonella Infantis Adhesion to Various Surfaces and In Vitro Antimicrobial Efficacy of Commercial Disinfectants

Salmonella Infantis poses a significant challenge in poultry production due to its persistence and resistance to disinfectants. This study investigated the survival of the S. Infantis strain on different surfaces and evaluated the efficacy of disinfectants in both preventing and treating biofilms. The survival of the tested S. Infantis strain was assessed on plastic and stainless steel surfaces after 24 and 48 h. The minimum inhibitory concentrations (MICs) of five disinfectants were determined, and their antiadhesion effectiveness was evaluated using crystal violet. The efficacy of biofilm treatment was evaluated by cell culturability. The results showed that the adhesion of S. Infantis was significantly higher on the plastic surface. The disinfectants were effective at reducing biofilm formation only within the first 24 h. Fresh solutions of disinfectants based on quaternary ammonium compounds exhibited the highest antimicrobial efficacy, while chlorocresol was the most effective for both the prevention and treatment of biofilms. The study results suggest that the presence of plastic surfaces may contribute to the dissemination of Salmonella. Additionally, the effectiveness of disinfectants varied based on storage conditions and contact time, while biofilms demonstrated reduced susceptibility compared to planktonic cells. However, given the laboratory scale of this study, further validation on a commercial scale is necessary to confirm these findings.

Formulation and Evolution of Herbal Shampoo

Shampoos are one of the cosmetic products used in daily life. Synthetic preservatives and detergents have sometimes been the cause of adverse effects among consumers. A more radical approach in reducing the synthetic ingredients is by incorporating natural extract whose functionality is comparable with their synthetic ingredients.this herbal shampoo was formulated using natural ingredient like Fenugreek seeds), Acacia concinna (shikakai), Sapindus mukorossi (reetha), Ocimum sanctum (tulsi), Aloe vera (aloe), Hibiscus rosa sinensis (china rose), Azadirachta indica (Neem), Lawsonia inermis (henna),Citrus lemon (lemon), with proven efficacy of hair care preparation is prepared. The combination of several such ingredient of herbal origin has made it possible to secure highly effective dry powder shampoo. The formulation at laboratory scale was done and evaluated for number of parameters to ensure its safety and efficacy.The main obeject of this present study is to prepare and evaluate an herbal shampoo and determine physiochemical function that emphasizes on safety.which is use to remove grease, dirt, dandruff..

Physicochemical and Antimicrobial Properties of Lactic Acid-Based Natural Deep Eutectic Solvents as a Function of Water Content

The interest in natural deep eutectic solvents (NADESs) in green technology as an alternative to organic solvents has grown over the past decades. In this work, for the first time, the effect of dilution with water on the physicochemical and antimicrobial properties of lactic acid-based NADES with choline chloride (NADES1), sorbitol (NADES2), and glucose (NADES3) was systematically studied. According to FTIR data, after the dilution of NADESs with water, the strong hydrogen bonds weakened, however, were not destroyed after dilution of up to 40% water. The dilution of NADES with water resulted in a linear decrease in density and refractive index and in a linear increase in pH. The equations for the prediction of NADES density, pH, and refractive index as a function of water content were calculated. The viscosity decreased by half after adding approximately 10% water. The initial viscosity of NADES2 and NADES3 was significantly different. However, after adding 20% of the water, the viscosity was almost the same. The most pronounced decrease in surface tension (by 46.7%) was found for NADES1. The water activity was decreased in the following order: NADES3 > NADES1 > NADES2. The dilution of NADES with water caused a gradual increase in water activity. NADES1 showed the lowest minimal inhibitory concentrations (MIC) (7.8, 3.9, and 0.98 mg/mL) and minimum bactericidal concentrations (MBC) (15.6, 7.8, and 1.95 mg/mL) for Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, respectively. The antimicrobial activity was decreased by 2–8 times after the addition of 40% water. The water activity for all tested NADES together with low pH could explain the antimicrobial effect. The revealed regularity can be useful for the prediction of NADES properties and for the selection of green solvents on a laboratory and industrial scale.

Enrichment of lithium ions for battery application by electrolysis through a nanoporous membrane

In recent years, lithium (Li) has become a valuable commodity widely used in rechargeable batteries. The present study aims to extract battery-grade lithium-ion, as lithium hydroxide (LiOH), from lithium chloride (LiCl) solution by the membrane electrolysis process. Experiments are performed using a commercial cation exchange membrane and an indigenous High flux-Nanofiltration 300 alkali resistant (HF-NF 300 AR) nanoporous membrane. The dual-chamber electrolytic cell incorporates a selective membrane to separate the feed and concentrate chambers containing LiCl solution and deionized water. These two chambers are connected with titanium electrodes through the external circuit. The in-situ design of the compact two-chambered acrylic electrolytic cell helps to separate metal ions from ionizable salts of sodium, lithium, magnesium, potassium, etc. The experiment is conducted on a laboratory scale by varying the LiCl concentration at voltages of 24 V and 36 V. The feed and concentrate solutions are analyzed for pH, conductivity, and total dissolved solids. Inductively coupled plasma-optical emission spectrometry evaluates the presence of metal ions in the solution. The study shows effective metal ion recovery and separation to achieve battery-grade Li.

A Review of the Measurement of the Multiphase Slug Frequency

The slug frequency (SF), which refers to the number of liquid slugs passing through a pipe during a specific time, is an important parameter for characterizing the multiphase intermittent flows and monitoring some process involving this kind of flow. The simplicity of the definition of SF contrasts with the difficulty of correctly measuring it. This manuscript aims to review and discuss the various techniques and methods developed to determine the slug frequency experimentally. This review significantly reveals the absence of a universal measurement method applicable to a wide range of operating conditions. Thus, the recourse to recording videos with high-speed cameras, which can be used only at a laboratory scale, remains often necessary. From the summarized state-of-the-art, it appears that correctly defining the threshold values for detecting the liquid slugs/elongated bubbles interface from physical parameters time series, increasing the applicability of instrumentations at industrial scales, and properly estimating the uncertainties are the challenges that have to be faced to advance in the measurement of SF.

Impact of Acid Rain on Release Characteristics of Heavy Metals in Low-Sulfur Tailings with Strong Acid Neutralization Capacity: A Case Study from Northern Guangxi, China

Tailing ponds are major sources of heavy metal pollution. Previous studies primarily focused on tailings with high sulfur content, with limited attention to low-sulfur tailings. This study explored the release behavior of Pb, Zn, and Cd from low-sulfur tailings under simulated acid rain conditions, considering factors such as pH, particle size, and weathering degree. Samples were collected from a lead–zinc tailing pond in the karst regions of northern Guangxi, China. Batch leaching experiments indicated that even with high acid neutralization capacity (ANC = 166.57–167.45 kg H2SO4/t), substantial heavy metal leaching occurred under acidic conditions (pH 2–3), with Pb, Zn, and Cd concentrations increasing 4–6 times compared to neutral conditions. Leachate concentrations were slightly higher in coarser particles than in finer ones, while weathering further enhanced metal release, particularly for Cd. These findings suggest that acid neutralization alone may not be sufficient to prevent heavy metal leaching in low-sulfur tailings exposed to acid rain. However, due to the laboratory scale of this study, further validation through field-scale or mesocosm experiments is necessary to confirm the observed trends and assess their implications for environmental risk management in karst regions.

Numerical model of a top-blown rotary converter preheating and charge heating with an oxy-fuel burner

Background The present work is conducted in the framework of the SisAl Pilot EU project, which aims to optimize silicon production in Europe by recycling materials and using carbon-emission-friendly technology. Silicon production experiments were conducted on laboratory and pilot scales in different types of furnaces, including top-blown rotary converters (TBRC) used as chemical reactors for molten slag-metal mixtures. In addition to experimental work, process optimization also relies on numerical modelling. Methods In this study, COMSOL Multiphysics® was used for the numerical testing of a new thermal design of TBRC by simulating its preheating and charge heating owing to an external heat source provided by an oxy-fuel burner. Results and conclusions The risk of slag solidification in TBRC during the aluminothermic reduction of silica was assessed. The model predicts that, with a useful burner power of 600 kW, the empty TBRC can be preheated to 1650°C in less than 30 min. Based on this model, the optimum burner power for maintaining the TBRC charge in a liquid state was determined. The influence of the TBRC inclination angle and its rotation frequency was studied numerically.

Multimode squeezed state for reconfigurable quantum networks at telecommunication wavelengths

Continuous variable encoding of quantum information requires the deterministic generation of highly correlated quantum states of light in the form of quantum networks, which, in turn, necessitates the controlled generation of a large number of squeezed modes. In this paper, we present an experimental source of multimode squeezed states of light at telecommunication wavelengths. Generation at such wavelengths is especially important as it can enable quantum information processing, communication, and sensing beyond the laboratory scale. We use a single-pass spontaneous parametric down-conversion process in a nonlinear waveguide pumped with the second harmonic of a femtosecond laser. Our measurements reveal significant squeezing in more than 21 frequency modes, with a maximum squeezing value exceeding 2.5 dB. We demonstrate multiparty entanglement by measuring the state's covariance matrix. Finally, we show the source reconfigurability by preparing few-node cluster states and measure their nullifier squeezing level. These results pave the way for a scalable implementation of continuous variable quantum information protocols at telecommunication wavelengths, particularly for multiparty, entanglement-based quantum communications. Moreover, the source is compatible with additional pulse-by-pulse multiplexing, which can be utilized to construct the necessary three-dimensional entangled structures for quantum computing protocols. Published by the American Physical Society 2024

Experimental and Numerical Study on Nonlinear Shear Behavior and Constitutive Model of Deep Shale Laminae Planes

The direct shear tests showed that the degradation of unevenness and waviness of the laminae plane is the primary reason for the dynamic decrease in shear strength. A shear constitutive model was proposed which considers the scale effect and the asperity geometry of the unevenness and waviness of the laminar plane. The evolution of the shear strength and stiffness with a normal stress and scale effect during the shearing of shale laminae planes was explored. The results show that high normal stress aggravates the stiffness hardening of laminae planes and forms larger peak shear stress and peak shear displacement. At the lab scale, the increase in the unevenness wavelength has a hardening effect on the shear stiffness and strength. The small-scale unevenness contributes most to the shear strength of shale laminae planes at the lab scale. At the field scale, the increase in the waviness wavelength has a softening effect on the shear stiffness and strength.

Evaluation and Prediction of Mechanical Properties According to Welding Methods of Ni 825/A516-70N Clad Plates

In this study, the microstructures and mechanical properties of different methods of FCAW (Flux-cored arc welding) + FCAW or FCAW + GTAW (Gas tungsten arc welding) welding on Ni825/A516-70N clad plate were investigated, using a double U groove angle on a laboratory scale. The amount of specimen deformation with FCAW + FCAW welding was ~1.5 mm, and that with FCAW + GTAW welding was ~3.6 mm. In the Vickers hardness tests, the average hardness value of the FCAW + GTAW welding specimens tended to be higher, and the hardness of the steel showed the same value. Also, in the tensile tests, the maximum strength and elongation of the FCAW + GTAW specimens were found to be higher. The SEM analysis of the welding boundaries of each specimen revealed the phenomenon of grain refinement in the specimens with FCAW + GTAW welding. This was due to the slow welding speed of this welding process and the rapid cooling rate caused by the relatively low layer thickness despite the relatively high number of weld passes. The computer simulation of the amounts of deformation were similar, with a value of 1.5 mm for FCAW + FCAW and 3.6 mm for the computer simulation, indicating the credibility of the simulation. In the computational simulation of butt welding, FCAW + GTAW showed high values for both residual stress and angular strain. The L-seam and C-seam of the demo vessel size were welded under the same conditions as the actual welding. The residual stress and angular deformation in the L-seam were 849 MPa and 2.3 mm for the FCAW + FCAW and 852 MPa and 2.9 mm for FCAW + GTAW. The residual stress and angular deformation in the C-seam were 920 MPa and 0.7 mm for FCAW + FCAW and 930 MPa and 0.9 mm for FCAW + GTAW, respectively.

Data Hub for Life Cycle Assessment of Climate Change Solutions—Hydrogen Case Study

Life cycle assessment, which evaluates the complete life cycle of a product, is considered the standard methodological framework to evaluate the environmental performance of climate change solutions. However, significant challenges exist related to datasets used to quantify these environmental indicators. Although extensive research and commercial data on climate change technologies, pathways, and facilities exist, they are not readily available to practitioners of life cycle assessment in the right format and structure using an open platform. In this study, we propose a new open data hub platform for life cycle assessment, considering a hierarchical data flow starting with raw data collected on climate change technologies at laboratory, pilot, demonstration, or commercial scales to provide the information required for policy and decision-making. This platform makes data accessible at multiple levels for practitioners of life cycle assessment, while making data interoperable across platforms. The proposed data hub platform and workflow are explained through the polymer electrolyte membrane electrolysis hydrogen production as a case study. The climate change environment impact of 1.17 ± 0.03 kg CO2 eq./kg H2 was calculated for the case study. The current data hub platform is limited to evaluating environmental impacts; however, future additions of economic and social aspects are envisaged.

Research on a New Method of Water Recovery from Biogas Plant Digestate

Digestate is a product with valuable fertilizing properties, remaining after the anaerobic fermentation process. An essential feature of the substance in question is its high water content of up to 97%. To improve the fertilizer value of the digestate, it is necessary to dehydrate it to produce a concentrated product. This paper determined the possibility of dewatering the digestate using an innovative reactor design. The study, conducted on a laboratory scale, used digestate from a Polish biogas plant. The dewatering technique described in the paper is based on the evaporation and condensation of water vapor on the inner surface of the reactor dome. The condensate accumulated on the leach trough and was directed to a storage tank. During the weeks of testing, 11.5 kg of condensate was separated from the initial weight of the digestate (32 kg), with a dry weight of 6.11%. The resulting condensate from dehydration had an average pH value of 9.0 and an average ammonium nitrogen content of 2.07 g∙kg−1. The economic calculations made in the paper allowed for estimating the expected savings associated with the management of digestate in Poland. The research showed the proposed technology’s high potential for dewatering digestate under laboratory conditions.

Three-phase flow measurement by dual-energy gamma ray technique and static-equivalent multi-phase flow simulator

There is a strong desire to use three-phase flowmeters in upstream operations because of their small size, portability, and cost-effectiveness. Traditional three-phase flowmeterstypically employ two main strategies: fully separating the flow into liquid and gas streams and measuring them using common two- and single-phase meters, or simplifying the direct measurement requirements by homogenization.In order to achieve accurate measurements with these meters, it is necessary to first create a suitable simulator for generating various multiphase flow regimes with minimal systematic error. Developing such a simulator on a laboratory scale, rather than using expensive test loops is a crucial and practical option.In this research, SEMPF as a Static-Equivalent Multi-Phase Flow with flexibility in creating different multi-phase flow regimes is introduced. In the following, the mechanism of action is validated for both homogenous two- and three-phase mixtures by using dual-energy gamma ray attenuation technique in the Monte Carlo simulator environment. Finally, the three-phase component fraction measurement accuracy by dual-energy gamma meter in three different modes of gasoil-, water-, and air-continuous mixtures were investigated. The experimental results show the maximum accuracy of 2.03 %, 7.23 %, and 5.09 % for gasoil phase measurement in three different conditions that the carrier phase is air, gasoil and water respectively.

Attenuation of bulk waves using locally resonant soil-coupled metabarriers

Abstract Low frequency ground-borne vibrations generated by transport infrastructure are one of the most serious causes of disturbance to the general population. One possibility to reduce this problem is to use the wave filtering properties of elastic metamaterials. However, their integration in the soil complicates the prediction of their response, and the influence of soil-structure interaction needs to be correctly evaluated for an efficient design. The aim of this work is to experimentally evaluate the efficiency of metamaterial trench barriers set in soil in attenuating vibrations, using low-frequency local resonance mechanisms. A lab scale model is proposed comprising different resonating structures and a cylindrical encasement is adopted to couple the structure to the soil. The influence of various parameters is evaluated, such as metamaterial structure, geometrical characteristics of the resonator, and constituent materials. Finite Element simulations are used to develop a suitable design, analysing mode shapes and resonance frequencies of structures with and without the surrounding encasement. Experimental modal analysis is then performed on the corresponding fabricated samples, providing both model validation and out-of-soil mechanical characterization. Finally, vibration transmission loss measurements are performed in a setup in which different resonant metamaterial barriers are embedded into the soil sample, allowing the evaluation of barrier performance. Results indicate that the metamaterial structures provide good attenuation of vibrations in selected intervals in the low to high frequency range (1–5 kHz), demonstrating the feasibility of the approach in a scaled sample. Preliminary data regarding the structures providing preferable design characteristics is also obtained. These results can be useful for the design of trench barriers scaled to large dimensions in more realistic applicative settings.

Design and Fabrication of Lab Scale Model on Water Pump Operated by Wind Energy Source

Design and Fabrication of Lab Scale Model on Water Pump Operated by Wind Energy Source

A New Three‐Port DC–DC Converter: Analysis, Design, and Verification for Hybrid Energy Systems

ABSTRACTA research study on the three‐port DC–DC converters is done in this article. The proposed converter is a power electronic unit with a low‐voltage, high‐voltage, and battery port. The power of the input ports can be transferred to the output port simultaneously and individually. In this converter, the power can flow bidirectional. In other words, the battery can be charged not only by the low‐voltage port but also by the returned energy from the high‐voltage port. Hence, the proposed converter can operate in step‐up and step‐down modes. Continuous input current, the low voltage stress on semiconductors, and the low count of the devices are other advantages of the converter. These features and the benefits mentioned above make the proposed converter proper for hybrid energy systems. This converter is analyzed in continuous conduction mode, resulting in mathematical equations. To validate these theoretical analyses, a laboratory scale of the converter performs at 50 kHz, 200 W, and 115 V.

Effect of temperature on the oxygen production capacity and growth of scenedesmus almeriensis

The optimal temperature and irradiance to maximise oxygen production were 39.3 °C and 512.5 μmol photons·m−2·s−1, respectively. These values were obtained by photorespirometry, which is a quick method to measure the photosynthetic and respiration rates of microalgae at a laboratory scale. With these conditions, the global oxygen production rate of S. almeriensis was 246.23 mgoxygen·gbiomass−1·h−1. When the culture temperature was controlled at 39.3 °C for 1 h per day, the daily oxygen production capacity of S. almeriensis increased from 3129.5 mgoxygen·gbiomass−1 to 3778.5 mgoxygen·gbiomass−1. However, keeping the temperature at 39.3 °C for a longer time caused a damage to the photosynthetic apparatus. This was validated using laboratory-scale bubble columns. The damage was reversible when heating the cells for <2 h, but keeping the temperature of the culture at 39.3 °C for 3 h led to an irreversible damage and a 6 % decrease in the photosynthetic performance. Controlling the overheating of microalgal cultures is crucial to maximise growth. In addition, the duration of the exposure to high temperatures should also be included into growth and taken in consideration.

Evaluation of large-scale poultry manure-derived biochar for efficient cadmium removal in zinc smelter wastewater

Cadmium (Cd), a carcinogen, is released from industrial activities like metal refineries and battery runoff, with significant contamination reported near zinc smelters in Korea. This study addresses the issue using an efficient, economical adsorption process with waste-derived biochar-based adsorbents known for high Cd removal. Poultry manure (PM), typically used as fertilizer, can lead to environmental pollution if mismanaged; therefore, it was pyrolyzed to produce biochar. The resulting poultry manure biochar (PMBC) was produced on a large scale (15 ton/day), demonstrating feasibility for large-scale implementation. The effectiveness of PMBC as an adsorbent for Cd was evaluated using wastewater discharged from a zinc smelter. The Cd adsorption capacity of PMBC (60.39 mg/g) was lower than that (302.0 mg/g) of hen manure biochar produced at a laboratory scale in our previous study but was comparable to other biochars reported in the literature. Response surface methodology analysis indicated that reaction time, dose, and agitation significantly influenced Cd removal by PMBC, whereas pH had a negligible impact. Notable contributions to Cd adsorption include the release of K+ from PMBC and the presence of O-containing functional groups. Under continuous flow conditions with real wastewater, Cd was not detected in the effluent for the initial 8 h, and PMBC sustained a removal efficiency of 40.77% until saturation was reached. The results from wastewater treatment and large-scale biochar production offer valuable insights into the potential of biochar as a medium for addressing environmental issues in real-world applications.