Industrial Scale Research Articles

Metabolic Performance of Mealworms and Black Soldier Fly Larvae Reared on Food and Agricultural Waste and By-Products

Mealworms and black soldier fly (BSF) larvae are two of the most reared insects at an industrial scale. Both may feed on by-products from agricultural and food industries. Feed efficiency is one of the most important aspects of such processes and varies between species and feed substrates and depends on the metabolic performance of the larvae. Compared to each other, both species may hold advantageous capabilities affecting their feed efficiency, likely depending on the feed substrate. We reared mealworms and BSF larvae on a diverse selection of by-products from agricultural and food industries, quantified major metabolic rates across their life spans, and compared their performances. The type of feed substrates had stronger effects on the growth of mealworms than on black soldier fly larvae. Generally, BSF larvae were advantageous in terms of the highest maximal specific growth rate (0.50–0.77 day−1) and feed assimilation rate (0.81–1.16 day−1) and shortest development period (23–25 days) but disadvantageous in terms of metabolic maintenance cost (0.07–0.21 day−1). In mealworms, the maximal specific growth rates were 0.02–0.11 day−1, the highest feed assimilation rates were 0.16–0.37 day−1, and the development period was at least 65–93 days, while maintenance was only 0.02–0.05 day−1. In contrast to the BSF larvae, the specific maintenance rate was weight dependent in the mealworms and lowest in the largest individuals. The combined outcome of these metabolic rates resulted in an average carbon net growth efficiency, NGE*avg of 0.16–0.40 in mealworms and 0.33–0.56 in BSF larvae across their life span. It thus seems that BSF larvae are more versatile and somewhat more efficient at converting diverse feed substrates into growth than mealworms. Differences in NGE*avg affected the substrate conversion efficiencies (i.e., the ratio of the weight gain of the larvae to the reduced weight of feed substrates) and may thus impact the overall outcome of insect farming.

Dynamic restructuring of electrocatalysts in the activation of small molecules: challenges and opportunities.

Electrochemical activation of small molecules plays an essential role in sustainable electrosynthesis, environmental technologies, energy storage and conversion. The dynamic structural changes of catalysts during the course of electrochemical reactions pose challenges in the study of reaction kinetics and the design of potent catalysts. This short review aims to provide a balanced view of in situ restructuring of electrocatalysts, including its fundamental thermodynamic origins and how these compare to those in thermal and photocatalysis, and highlighting both the positive and negative impacts of in situ restructuring on the electrocatalyst performance. To this end, examples of in situ electrocatalyst restructuring within a focused scope of reactions (i.e. electrochemical CO2 reduction, hydrogen evolution, oxygen reduction and evolution, and dinitrogen and nitrate reduction) are used to demonstrate how restructuring can benefit or adversely affect the desired process outcome. Prospects of manipulating in situ restructuring towards an energy-efficient and durable electrocatalytic process are discussed. The practicality of pulse electrolysis on an industrial scale is questioned, and the need for genius schemes, such as self-healing catalysis, is emphasized.

All‐Polymer Solid Desiccant With High Moisture Capture Capacity and Fast Sorption Kinetics

ABSTRACTDesiccants play crucial importance in both daily life and industrial production. The development of low‐cost and easy industrial scale production all‐polymer solid desiccants with high water adsorption capacity, low regeneration temperature, and fast sorption kinetics remains great challenges. Herein, we report a novel all‐polymer porous solid desiccant (APPSD) with high moisture capture capacity, low regeneration temperature, and fast sorption kinetics via a new zero‐waste, eco‐friendly, and easily scaled‐up process. The present APPSD could adsorb 0.8 g/g water vapor at 70% relative humidity (RH) within 1.5 h, and 1.9 g/g at 90% RH within 2.0 h at 25°C, exhibiting fast adsorption kinetics. The equilibrium moisture adsorptive capacity is as high as 2.16 g/g at 90% RH and 25°C, much higher than most reported solid polymer desiccants without hygroscopic salts under the same conditions. Amazingly, more than 92% of the absorbed water could be released at 40°C and 20% RH within 30 min, demonstrating extreme low regeneration temperature and high regeneration efficiency. Furthermore, almost no performance decline was observed during a 20‐cycle adsorption–desorption measurement, showing excellent recycling stability.

Design, Scale‐Up, and Dynamic Simulation of a Patented Bayonet Reactor for Commercial Hydrogen Production via Sulfur‐Iodine Water Splitting

ABSTRACTThe sulfuric acid decomposition reactor is a key component of the iodine‐sulfur thermochemical cycle process. The design of the sulfuric acid decomposition reactor requires excellent corrosion resistance and mechanical strength performance. In this work, a patented reactor on a pilot scale was scaled up to an industrial scale. A plant equipment design for an industrial‐scale reactor was performed. Based on an integrated inherent safety design approach, it was determined that the optimal thickness was 110 mm, and the design passed all stress analysis tests. With a minimum targeted hydrogen production rate of 1000 kg/h, the process design yielded a reactor with a diameter of 7 m and a height of 30 m, while silicon carbide was chosen as the construction material. The scaled‐up reactor was dynamically simulated in MATLAB. Simulink demonstrated that both the reactor temperature and product flow rates successfully produced a stable response within 1.8 and 4 h of operation, respectively.

Efficient utilisation of waste steel slag in slag-making process of all-scrap electric arc furnaces

A novel technique to recycle waste steel slag is to optimise the foam slag process of all-scrap electric arc furnaces (EAFs). The influence of waste steel slag addition on the basicity of final slag was studied, as slag basicity significantly affects foaming performance. The minimum control requirement of not less than 1.8 was obtained to calculate the maximum mass of waste steel slag. The above results were obtained through the use of thermodynamic calculation software Factsage8.3 and theoretical calculations. The properties of the foam slag were investigated, revealing improved effective viscosity. The optimised foaming index ranged from 2.27 to 2.65 s, compared with 1.63 to 2.45 s before optimisation. The optimisation was achieved by controlling the amount of waste steel slag and other additives, as well as the usage of oxygen and carbon powder. The average consumption reduction of oxygen, carbon powder, and electricity was 2.68 Nm3/t steel, 1.12 kg/t steel and 10.12 kWh/t steel in the industrial trials, respectively. The degree of metallisation has increased due to the reduction in oxygen consumption and slag production. It was observed that waste steel slag can be recycled successfully as an additive on an industrial scale.

Phase Equilibrium of CO2 Hydrate with Rubidium Chloride Aqueous Solution

Salt lakes are a rich source of metals used in various fields. Rubidium is found in small amounts in salt lakes, but extraction technology on an industrial scale has not been developed completely. Clathrate hydrates are crystalline compounds formed by the encapsulation of guest molecules in cage-like structures made of water molecules. One of the most important properties for engineering practices of hydrate-based technologies is the comprehension of the phase equilibrium conditions. Phase equilibrium conditions of CO2 hydrate in rubidium chloride aqueous solution with mass fractions of 0.05, 0.10, 0.15 and 0.20 were experimentally investigated in the pressure range from 1.27 MPa to 3.53 MPa, and the temperature was from 268.7 K to 280.6 K. The measured equilibrium temperature in this study decreased roughly in proportion to the concentration of the RbCl solution from the pure water system. This depression is due to the lowering of the chemical potential of water in the liquid phase by the dissolution of RbCl. Experimental results compared with other salt solution + CO2 hydrate systems showed that the equilibrium temperatures decreased to a similar degree for similar mole fractions.

Pressure and temperature response and phase transition path during small hole leakage in a near-industrial scale CO2 pipe

ABSTRACT As a large-scale CO2 migration method, pipelines play a crucial role in the CCUS industry chain. Small hole leakage caused by self defects, fatigue and corrosion, and natural disasters is a common accident in CO2 pipelines. When leaked CO2 is sprayed out through a small hole, the temperature inside the pipeline drops sharply under the Joule Thomson effect. This sudden temperature drop significantly reduces the toughness of the material, increases the risk of brittle fracture. In order to improve the CO2 pipeline release database, a new industrial scale CO2 pipeline has been built. The CO2 release experiments were carried out by using this experimental device. The experimental results showed that the pressure drop rate was fast under high pressure and then slowed down when the pressure dropped below the critical pressure, with the coexistence of gas and liquid. Rapid pressure drop and slight rebound occur during the leakage process, and low initial pressure leads to a more pronounced pressure plateau effect. Dense-phase CO2 leakage produced more dry ice than supercritical state, and the far field sublimation effect was more significant. In practice, particular attention should be paid to safety far from the leakage end.

Effects of Superphosphate on Greenhouse Gas Emissions and Compost Quality During Industrial Scale In-Vessel Swine Manure Composting

Composting is an environmentally friendly method for transforming the nutrients present in livestock manure into organic fertilizer. In this study, the compost quality-enhancing and N2O and CH4 emissions-reducing effects of superphosphate were investigated during industrial-scale in-vessel composting of swine manure. Alongside a control group, three different doses of superphosphate were tested: 5% (SSP5), 10% (SSP10), and 15% (SSP15). The results revealed that the superphosphate reduced the N2O and CH4 emissions by 18.5–26.3% and 15.8–25.1%, respectively. In addition, the superphosphate enhanced both the N and P contents of the compost. However, it had an adverse impact on compost maturity, with the SSP15 dose showing the lowest germination index (GI) at 70.4% and the highest electrical conductivity (EC) at 9.04 mS·cm−1. These findings suggest that superphosphate has potential for greenhouse gas mitigation and nutrient augmentation in industrial composting. Although the economic benefits of superphosphate addition for GHG reduction are limited, the technology holds considerable economic potential for nitrogen conservation. Further investigations should focus on combining superphosphate addition with other improvements, considering both compost quality and economic viability.

Analysis of Carbon Emission Reduction Potential in the Pilot of a "Zero-free City" in Chongqing

The construction of "zero-free cities" is an effective plan to achieve the carbon peak plan, reduce pollution and carbon emissions, and promote a circular economy. Based on the WARM model and Emission factor method, the total carbon emission reduction of solid waste sources and disposal in each field during the implementation of the zero-free city policy in Chongqing （2017-2021） was calculated, and the total carbon emission reduction of solid waste in each field in 2025 was predicted by scenario. The results showed that： ① After the implementation of cleaner production and green manufacturing policies in Chongqing, the generation intensity of general industrial solid waste decreased to 0.20 t·（104 yuan）-1 in 2021, and the carbon emission reduction in the industrial sector had been increasing since 2020. Due to the growth of the economy and living level, the per capita production of food waste, domestic waste, and e-waste increased, failing to reduce emissions at the source in these areas. In addition, the promotion of green food and organic agricultural products and the restriction of the use of chemical fertilizers and pesticides could be strengthened to further reduce source emissions in the agricultural field. ② General industrial solid waste, construction waste, and straw were the key areas to achieve carbon emission reduction, and their carbon emission reductions were predicted to increase to 2 796.64×104, 538.54×104, and 99.07×104 t in 2021. Respectively, reducing the landfill volume in the above fields is the key to emission reduction. In the field of daily life, the collection and transportation of solid waste should be improved, the sorting process and disposal facilities should be refined, and the resource recycling rate should be improved to reduce its carbon emissions. Due to the improvement of the collection level and the application of straw feed and fertilizer, the carbon emission reduction of straw and agricultural film is generally rising, and the proportion of straw and livestock manure directly returned to the field should be reduced in the agricultural field, and the allocation of biomass disposal facilities to promote the co-disposal of the two may be the best means of carbon emission reduction. ③ In 2025, the predicted carbon emission reductions in Chongqing under the BAU scenario and the PLAN scenario were 2 289.78×104 and 2 750.31×104 t, respectively, indicating that the upgrading and transformation of local industries and the large-scale scale of the renewable resources industry have achieved good carbon reduction benefits. With the construction and improvement of various waste disposal facilities in 2025, the carbon emission reduction of the solid waste disposal process in various fields will continue to increase, but the carbon emissions of hazardous waste, municipal sludge, and livestock and poultry manure will still be in a state of growth due to the possible increase in total output in the future.

Room-Temperature Vortex Fluidic Flow Chemistry Synthesis of Full Color Carbon Dots.

Carbon dots (CDs) as a new class of photoluminescent zero-dimension carbon nanoparticles have attracted significant research interests owing to their extraordinary opto-electro-properties and biocompatibility. So far, almost all syntheses of CDs require either heat treatment or exertion of high energy fields. Herein, a scalable room-temperature vortex fluidic method is introduced to the CDs synthesis using the angled vortex fluidic device (VFD). By judicious selection of the solvent, typical CDs precursor of phenylenediamine has been converted into high crystalline CDs through VFD processing. The VFD-synthesized CDs cover the full color spectrum from blue to red with the highest quantum yield of 45.6%. The synthesis shows that the dynamic thin liquid film generated by VFD spun at high rotational speed (7 - 9 k RPM) is able to induce cycloaddition reactions. The new method for CD synthesis is facile, occurring under ambient conditions in the VFD, potentially offering industrial scaling up of production of full color carbon dots.

Recovery of N-Methylmorpholine N-Oxide (NMMO) in Lyocell Fibre Manufacturing Process

The lyocell process offers an environmentally friendly strategy to produce regenerated cellulose fibre from biomass. However, it is critical to recover and reuse the N-methyl-morpholine-N-oxide (NMMO) solvent to maximize the environmental benefits and lower the cost. This article reviews NMMO recovery and characterization techniques at the lab and industrial scales, and methods to limit the NMMO degradation during the process. The article also presents the results of a pilot study investigating the recovery of NMMO from lyocell manmade cellulosic fibre (L-MMCF) manufacturing wastewater. The work described includes the development of a calibration curve for the determination of NMMO content in aqueous solutions using Fourier Transform Infrared Spectroscopy (FTIR). Successful NMMO recovery from the wastewater was achieved using a rotary evaporator: the final NMMO concentration was 50, i.e., ready for use in the lyocell process, and no NMMO degradation was observed. The knowledge in this paper will support advances in L-MMCF manufacturing and the reduction in textile environmental footprint.

Design Optimization of Pressurized Gyration Technology: Orifice Height Level Effects on Production Rate and Fiber Morphology

AbstractElectrospinning and pressurized gyration are two widely adopted methods for polymeric fiber production, valued for their simplicity, versatility, and relatively low environmental impact. Despite its advantages, electrospinning has notable limitations, including low production efficiency and significant safety concerns. Pressurized gyration, however, offers greater productivity and a safer, more sustainable process, making it an excellent candidate for industrial scaling. To fully realize this potential, optimizing the pressurized gyration process is essential for enhancing efficiency and achieving sustainable large‐scale fiber production. In this study, the effects of vessel orifice height on the production rate and fiber morphology in pressurized gyration are explored. A series of experiments is conducted using a 15 wt.% polycaprolactone (PCL) solution, with vessels of identical diameter but differing orifice heights 7.5, 15, and 22.5 mm tested under pressures of 0, 0.1, 0.2, and 0.3 MPa, all at a constant rotational speed of 13 000 rpm. The 7.5 mm orifice height demonstrates the highest production rate under pressure while increasing orifice height led to finer fiber diameters, better alignment, and smaller beads. These findings underscore the importance of optimizing vessel design, along with process and solution parameters, for scaling up pressurized gyration fiber manufacturing to meet industrial demands.

Recent developments in moving bed biofilm reactor (MBBR) for the treatment of phenolic wastewater -A review

BackgroundPhenol, a toxic and carcinogenic compound found in industrial effluent, poses a severe threat to the environment and aquatic life. Conventional methods such as physio-chemical techniques have limitations in efficiency, cost, and sustainability, leading to the development of advanced hybrid approaches like the Moving Bed Biofilm Reactor (MBBR) to treat phenols. Review methodIn this study, we aimed at an in-depth review of MBBR for the remediation of phenolic wastewater at an industrial scale. The review uses a methodology that involves a comparative analysis of various conventional methods, including activated sludge process (ASP), sequencing batch biofilm reactor (SBBR), Fluidized Bed Biofilm Rector (FBBR), and trickling filter (TF) with MBBR, to determine their efficacy in phenol degradation. In this context, a thorough bibliometric assay of MBBR is carried out to understand the recent publication trends. The study also examines the impact of different types and shapes of bio-carriers and their filling ratios on phenol biodegradation. Significant findingThe present work demonstrates the feasibility of using an aerobic MBBR along with a Fenton-like system (advanced oxidation processes) to treat phenolic effluent LCCA is discussed for selected treatment methods for assessing the sustainability aspects. In light of recent advancements, future research endeavors should prioritize the refinement and optimization of MBBR systems to strengthen their efficiency and sustainability, thus paving the way for a greener and cleaner future.

The interplay of irradiated- and shaded zones in photoreactor scale-up

Photochemical processes enable highly-selective synthesis routes under mild reaction conditions. Yet, photoreactions are seldom implemented on industrial scale. One of the main challenges is the exponential light attenuation with increasing optical depth. As a result, few photons are available at positions far from the light source, leading to shaded zones of low reactivity. To study the effect of shaded zones, a compartment photoreactor model is presented and used for optimization of the reaction conditions, in particular during scale-up. Using photooxidation in a Taylor-flow capillary reactor as a benchmark case, the photosensitizer concentration, the light intensity and liquid mixing are identified as the key parameters for the formation and impact of shaded zones on reactor performance. It is shown that shading reduces the conversion already on lab-scale by up to 13% for operating conditions with high photosensitizer concentration and light intensity. In an upscaled reactor, intensified liquid mixing leads to an up to 4.3-fold increase in conversion

The microalgal sector in Europe: towards a sustainable bioeconomy.

Microalgae are a diverse group of photosynthetic microorganisms that can be exploited to produce sustainable food and feed products, alleviate environmental pollution, or sequester CO2 to mitigate climate change, among other uses. To optimize resource use and integrate industrial waste streams, it is essential to consider factors such as the biology and cultivation parameters of the microalgal species and strains, as well as the cultivation system and processing technologies employed. This paper reviews the main commercial applications of microalgae (including cyanobacteria) and examines the biological and biotechnological aspects critical to the sustainable processing of microalgal biomass and its derived compounds. We also provide an up-to-date overview of the microalgal sector in Europe considering the strain, cultivation system and commercial application. We have identified 146 different microalgal-derived products from 66 European microalgae producers, and 49 additional companies that provide services and technologies, such as optimization and scalability of the microalgal production. The most widely cultivated microalgae was 'spirulina' (Limnospira spp.), followed by Chlorella spp. and Nannochloropsis spp., mainly for human consumption and cosmetics. The preferred cultivation system in Europe was the photobioreactor. Finally, we discuss the logistic and regulatory challenges of producing microalgae at industrial scale, particularly in the European Union, and discuss the potential of new genomic techniques and bioprocessing to foster a sustainable bioeconomy in the microalgal sector.

Quantum internal models for Solvency II and quantitative risk management

Abstract This paper extends previous research on using quantum computers for risk management to a substantial, real-world challenge: constructing a quantum internal model for a medium-sized insurance company. Leveraging the author’s extensive experience as the former Head of Internal Model at a prominent UK insurer, we closely examine the practical bottlenecks in developing and maintaining quantum internal models. Our work seeks to determine whether a quadratic speedup, through quantum amplitude estimation can be realised for problems at an industrial scale. It also builds on previous work that explores the application of quantum computing to the problem of asset liability management in an actuarial context. Finally, we identify both the obstacles and the potential opportunities that emerge from applying quantum computing to the field of insurance risk management.

Comportamento reprodutivo e requerimento térmico de pitaias no extremo norte da amazônia

ABSTRACT The objective of this work was to assess the reproductive phenology and thermal requirements of two dragon fruit species grown under the climate conditions of northern Amazon. The experiment was carried out in the municipality of Boa Vista, Roraima, Brazil, during two production cycles (2020-2021 and 20212022). Two dragon fruit species were used: Hylocereus costaricensis, which produces cylindrical fruits with a red skin and purple pulp; and Hylocereus polyrhizus, which produces elongated fruits with red skin and pulp. Ten plants of each species were selected and divided into four quadrants; ten cladodes were selected per quadrant and two flower buds were selected per cladode, totaling 800 flowers for each species. The plants were monitored from the beginning of flower bud intumescence until fruit harvest. Phenological periods were evaluated from production pruning to fruit harvest, based on the phenological stage descriptions of the Biologische Bundesanstalt Bundessortenamt and Chemical Industry (BBCH) scale. Climate conditions affected the species over the years, mainly due to variations in air temperature preceding phenophases. Variations between years increased the production cycle in 20 days for H. costaricensis and 34 days for H. polyrhizus from the first (2020-2021) to the second (2021-2022) production year. Organoleptic properties of species showed excellent results, including soluble solids (SS), titratable acidity (TA), and SS to TA ratio. Complete physiological maturity of H. costaricensis and H. polyrhizus fruits occurred at 31 and 38 days after anthesis, respectively, when the fruits presented an intense red skin and pulp.

The impact of fermentation length and dough composition on the stability of liquid sourdough starters

Sourdough breadmaking on an industrial scale requires robust, well-performing starters that bring attractive characteristics to the product. The active nature of liquid starters provides a faster fermentation process compared to their dehydrated counterparts. However, liquid sourdough starters require meticulous management in order to maintain stability and functionality during cold storage at 4 °C.This study investigated the stability of three liquid sourdough starters during storage and also the impact of prolonged fermentation, the addition of diastatic malted wheat flour, and a neutralising agent (CaCO3).The sourdough starters were evaluated for their microbial viability and metabolic activity at three individual time points during 16 weeks of cold storage. The microbial composition was analysed using culture-dependent and culture-independent methods, and metabolic changes were investigated using chromatographic methods.Two types of sourdough starter showed satisfying viability of lactic acid bacteria (> 7 log CFU/g) and metabolic stability throughout 16 weeks of cold storage. The introduction of malted wheat flour and CaCO3 caused a decline in viability to <7 log CFU/g within 8 weeks in the third sourdough starter type and additionally revealed an ongoing metabolic activity of this sourdough starter during cold storage.Prolonged fermentation influenced the free amino acid profile, whereas adjusting the sourdough starter formula resulted in a different fungal microbiota and increased levels of fermentable substrates (maltose), organic acids (lactic acid), and aromatic compounds (alcohol and aldehydes).These findings provide stakeholders and researchers in sourdough fermentation technology with new insights concerning the stability of cold-stored liquid sourdough starters.

Suspensions of antibiotics in self-emulsifying oils as a novel approach to formulate eye drops with substances which undergo hydrolysis in aqueous environment

The aim of this study was to develop eye-drops with cefuroxime (CEF) sodium or vancomycin (VAN) hydrochloride, antibiotics that are instable in water. Anhydrous self-emulsifying oils (SEO) are proposed as a carrier and antibiotics are suspended. In the contact with tear fluid, the formulation should transform into emulsion, with fast dissolution of an antibiotic. CEF or VAN (5% w/w) was suspended in SEO carriers prepared by dissolving surfactants (Tween 20 or Span 80 5% w/w) in Miglyol, castor oil, or olive oil. Formulations with or without sodium citrate (2% w/w) were compared. Six-months or 1-year stability tests were carried out at 40 °C. The content of CEF and VAN was evaluated using HPLC and the potency of the antibiotic was assessed with agar diffusion method. In contact with water, drug particles suspended in SEO dissolved rapidly and o/w emulsion was formed. After 1-year at 40 °C, the content of degradation products was at most 0.5% in CEF and 4.0% in VAN formulations. The agar diffusion assay has shown that CEF and VAN loaded into SEO retained its potency against the sensitive microorganisms comparable to an aqueous solution. Therefore, SEO can be used as a novel carrier for the active substances which may not require improved solubility or absorption but need to be protected from moisture. This is a formulation that can be produced on industrial scale, with no limitation of stability or drug concentration.

Development Of Sustainable Denim Products with Foam Application Technique in Denim Washing Processes

In denim washing processes, there is an increasing trend towards methods with less water, less chemical and less energy consumption in line with the goals of reducing environmental impacts and sustainability. Foam application technique significantly reduces water and energy consumption and minimizes the use of chemicals compared to conventional washing methods. Foam-based applications preserve the aesthetic and textural properties of the denim fabric and greatly limit wastewater generation. In particular, methods using low-density foams allow the desired effects to be achieved without damaging the appearance and durability of the fabric. These innovative techniques are seen as an important tool for the textile industry to achieve its sustainability goals [1-2]. In this study, the possibilities of using foam application technique to reduce the environmental impacts of high water and chemical consumption in conventional denim washing processes were investigated. The possibility of this technique, which makes it possible to obtain similar or superior results with less resource utilization compared to conventional methods in denim washing processes, has been evaluated as an alternative that can be broadened in the sector. Within the scope of the study, the physical performance characteristics of the products before and after washing such as tear strength, tensile strength, elasticity, residual extension, colour fastness to water, colour fastness to perspiration and colour fastness to rubbing were analyzed. In addition, based on the sustainability perspective, a pathway will be created for the use of this process in industrial scale applications with creative approaches in the development of environmentally friendly denim products.