Medium Capacity Research Articles

A Polyphenol Decorated Triplex Hybrid Biomaterial: Structure-Function, Release Profiles, Sorption, and Antipathogenic Effects.

Herein, nonwoven alkali modified flax substrates were coated with incremental levels of chitosan, followed by immobilization of tannic acid, via a facile "dip-coating" strategy to yield a unique hierarchal "triplex" hybrid biomaterial, denoted as "THB". The characterization of the physicochemical properties of THB employed complementary spectroscopic (IR, Raman, and NMR) techniques, which support the role of hydrogen bonding and electrostatic interactions between the components: chitosan as the secondary biopolymer coating and the tertiary adsorbed polyphenols. XRD and SEM techniques provide further structural insight that confirms the unique semicrystalline nature and porous hierarchal structure of the biocomposite. The THBs present a polyphenol kinetic release profile that follows the Korsmeyer-Peppas model that concurs with Fickian diffusion for heterogeneous polymer systems. Furthermore, these systems demonstrate a tailored solvent uptake capacity (up to 4 g/g) in aqueous PBS media. Antipathogenic activity tests revealed 95% elimination of pathogens (E. coli, S. aureus, and C. albicans) at a dose of 50 mg for the THB system. The trend in the structure-property relationships for the THB systems indicates synergistic effects of electrostatic multiform interactions between protonated chitosan and the polyphenol units. Herein, we report the first example of a unique hierarchal biomaterial via a facile design strategy for diversiform roles as responsive adsorbents for environmental remediation to biomedical applications (e.g., controlled release, topical administration, or antimicrobial surface coatings).

ASSESSMENT OF THE ECONOMIC EFFICIENCY OF USING ORGANO-MINERAL FERTILIZERS AND GROWTH STIMULANTS IN POTATO FIELDS CULTIVATED IN THE CONDITIONS OF FOOTHILL ZONE

The article presents the results concerning calculations of the economic efficiency of the potato harvest, obtained under the influence of the equivalent amounts of organo-mineral fertilizers and different ways of applying growth-stimulating bio-liquid in the post-forest medium capacity brown soils of the foothill zone of the Republic of Artsakh, in the early-ripening impala variety potato sowings, cultivated under arid conditions. According to economic calculations of the average data of three-year experimental research studies, it was revealed that the highest yield and economic efficiency in potato plantings was provided by the version of fractional application of bio-liquid and organomix norms (bio-liquid 14 l/ha-1 norm to soak the planting material 3 days before sowing, 5 t/ha-1of organomix in sowing and 3 t/ha-1ha norm to be applied with nutrition), which ensured a high-quality potato harvest of 36.47 t/ha-1 and an additional benefit of 2 million 152.6 thousand AMD. At the same time, providing a high compensation for the additional costs incurred, with the results of impact and post-impact per 1 dram spent, a net profit of 3.95 AMD. The above-mentioned version of fertilization was proposed for wide implementation in the region and in agro-zones with similar soil and climatic conditions of the Republic of Armenia.

Ultrasound Activated Clay: Preliminary Study of PB And as Removal in Aqueous Media

Objective: The objective of this study was to evaluate the removal of Pb and As in aqueous media by activated clay (AC). Theoretical Framework: Heavy metals in water represent a risk to health and ecosystems, their removal through new materials is a challenge for the industry. Method: The methodology adopted for this research comprises in that natural clay (NC) was activated with sodium chloride and phosphoric acid followed by sonication. A synthetic solution of Pb and As was prepared at different pH. Results and Discussion: The zero charge point was found to be 7.10 for AC and 8.02 for NC, the ζ potential was found to be between - 41.15 and - 45.43 mV in the pH range of 4 to 12, with degree of crystallinity of 97.24% and crystal size of 2.85 nm determined by XRD. FTIR analysis allowed the identification of functional groups with chelating capacity. Was observed As removal of 75.51% (110.40 mg/g) and 23.23% (58.13 mg/g) and 97.75% (106.41 mg/g) and 100.0% (206.53 mg/g) for Pb with AC and NC respectively at pH 6 and 8. Research Implications: Los reaultadoe encontrados sugieren que la arcilla activada se convierte en un material alta capacidad de adsorción de metales pesados en sistemas multimetal. Esta cualidad se debe al incremtno de grupos funionales en su superficie y al tamaño nanométrico que incrementa el área de contacto. Originality/Value: Activation of the clay with sodium chloride and weak acid followed by sonication is an environmentally friendly process that produces a material with high heavy metal removal capacity in aqueous media.

New insights on zero-valent iron permeable reactive barrier for Cr(VI) removal: The function of FeS reaction zone downstream in-situ generated by sulfate-reducing bacteria

The biogeochemical behavior downstream of the zero-valent iron permeable reactive barrier (ZVI-PRB) plays an enormous positive role in the remediation of contaminated-groundwater, but has been completely neglected for a long time. Therefore, this study conducted a 240-day SRB-enhanced ZVI-PRB column experiment, focusing on what exactly happens downstream of ZVI-PRB. Results show that biosulfidation of SRB inside ZVI-PRB prolonged the complete Cr(VI) removal longevity of ZVI-PRB from 38 days to at least 240 days. More importantly, unlike previous studies that focused on improving the performance of ZVI-PRB itself, this study found an in-situ generated FeS reduction reaction zone downstream of the ZVI-PRB. When the ZVI-PRB fails, the downstream reaction zone can continue to play a role in Cr(VI) removal. The maximum Cr(VI) removal capacity of the aquifer media from the reaction zone reached 155.1mg/kg, which was 39.7% of commercial ZVI capacity. The reduction zone was further confirmed to be predominantly FeS rather than FeS2. Biogeochemistry occurring within and downstream of ZVI-PRB leads to the formation of FeS. Gene sequencing revealed significantly higher SRB abundance downstream of ZVI-PRB than within the ZVI-PRB. The understanding of the downstream FeS reaction zone provides new insights for more effective remediation using ZVI-PRB.

Maximizing resource efficiency with dairy and municipal wastewater as nutrient media for Chlorella vulgaris with simultaneous CO2 sequestration

Addressing critical environmental challenges such as greenhouse gas emissions, global warming, and eutrophication demands urgent and innovative solutions. In recent years, microalgae have emerged as a promising avenue for addressing these pressing issues. In this study, the combination of dairy and municipal wastewater is proposed as a culture medium for cultivating microalgae strains capable of sequestering atmospheric CO2. Specifically, the growth of Chlorella vulgaris was investigated using Bold's basal medium, along with varying concentrations of municipal and dairy wastewater, both with and without CO2 supplementation, to assess their CO2 capture potential. Concurrently, the efficiency of chemical oxygen demand (COD), total nitrogen, potassium, and phosphate removal from the wastewater was evaluated. Additionally, the combination of wastewater media with CO2 supplementation yielded the highest CO2 uptake rates, indicating the feasibility of simultaneous CO2 capture during microalgae cultivation. Media composition with 25% municipal wastewater: 75% dairy wastewater supplemented with CO2 demonstrated superior COD elimination with a higher percentage of nutrient removal from wastewater compared to other wastewater proportions. The nutrient removal capacity of aforementioned media also comes in line with high CO2 sequestration rate (13.57 mg L−1 h−1). These findings underscore the potential of utilizing wastewater from diverse sources as a viable culture medium for microalgae cultivation, facilitating concurrent CO2 capture and wastewater treatment.

Co-based metal-organic frameworks for enhanced nickel adsorption and its impact on nitrifying microbial activity.

The release of nickel "Ni(II)" into aquatic environments is of great concern because of environmental and health issues. Metal-organic frameworks (MOFs) are one of the most promising technologies for removing heavy metals from water. In this work, an octahedral Co-based MOF (Co-MOF) was synthesized with a high Ni(II) removal capacity (qmax of 1534.09 ± 45.49 mg g-1) in aqueous media. For the first time, the effect of Co-MOF alone and in co-exposure with Ni(II) on nitrifying microbial consortium was assessed using dynamic microrespirometry. A single concentration of Co-MOF had no significant effects on nitrifying microbial consortium, while the concentration of Ni(II) exerted non-competitive inhibition on the nitrifying microbial consortium with an IC50 of 1.67 ± 0.03 mg L-1. In addition, the theoretical speciation analysis showed a decrease of 40% of IC50 when the free Ni(II) concentration was considered. Co-exposure of Co-MOF and Ni(II) during the nitrifying process allowed us to conclude that Co-MOF is an effective adsorbent for Ni(II) and can be used to mitigate the inhibitory effects of nickel on nitrifying microbial consortia, which is crucial for maintaining the good operation of wastewater treatment and balance of nitrogen cycle.

Effect of different nitrogen source and Saccharomyces cerevisiae strain on volatile sulfur compounds and their sensory effects in chardonnay wine

Three commercial Saccharomyces cerevisiae strains with low, medium, and high H2S-producing capacity were chosen to investigate the effect of yeast assimilable nitrogen (YAN) levels and composition on volatile compounds in a chemically defined medium, specifically high, medium, and low initial YAN levels with varying proportions of DAP or sulfur-containing amino acids (cysteine and methionine). The results revealed that the initial YAN containing a larger proportion of diammonium phosphate resulted in a higher YAN consumption rate during the early stages of fermentation. The yeast strain had a greater effect on the volatiles than the YAN level and composition. Keeping the total YAN constant, a higher proportion of sulfur-containing amino acids resulted in a considerably higher production of 3-methylthiopropanol. The sensory impact of three key volatile sulfur compounds was investigated in a Chardonnay wine matrix, indicating that 3-methylthiopropanol at subthreshold or greater concentrations was effective in enhancing the cantaloupe aroma.

Sustainability and circularity assessment of the potential of a biofuel produced from black liquor as a substitute for conventional fuels

The European Bioeconomy Strategy aims to accelerate the deployment of a sustainable European bioeconomy to maximize its contribution to the 2030 Agenda and its Sustainable Development Goals (SDGs), as well as to the Paris Agreement on climate change. In this context, transport is considered as a key sector, with aviation and shipping playing an important role due to the need to meet its huge demand. In order to reduce potential emissions from the transport sector, the use of biofuels could be considered as a solution. However, with the aim of using biofuels to replace conventional fuels, it is important to assess their cost-effectiveness and feasibility, and in this aspect the valorization of waste streams for their production could help to meet this challenge. This is the framework of this research report, which is based on the use of black liquor (BL) from pulp and paper production to produce biofuel through a hydrothermal liquefaction (HTL) unit. Three technological designs and production capacities were considered: full extraction of the oil phase and its upgrading by catalytic hydrothermal deoxygenation (Scenario 1, S1), partial extraction of the oil phase (Scenario 2, S2) and full extraction but without upgrading (Scenario 3, S3). Low (100 t/d), medium (300 t/d) and high (600 t/d) production capacities were regarded.From the modelling data, a life cycle perspective was adopted, taking into account both the environmental analysis (LCA) and the life cycle costs (LCC), as well as the circular potential using different performance, resource-flow circularity and economic indicators. In addition, a composite indicator, CILCA-LCC-CA, has been proposed to obtain a single score taking into account the three assessments: environmental, cost and circularity. The results obtained show that S3, with a production of 300 t/d, has the lowest environmental impact and the highest profitability corresponds to a capacity of 600 t/d. In terms of circularity, S3 also shows the best performance, mainly due to its higher resource productivity and lower energy intensity. These results are in line with those obtained for the composite indicator, and also show that higher production capacities and a simple but efficient process technology, such as S3, is the alternative with the highest potential for both sustainability and circularity.

Mode-dependent observer-based secured hybrid-driven reliable control for semi-Markov jump cyber–physical systems with DoS attacks

This study focuses on the issue of secured observer based hybrid-triggered quantized reliable control design for semi-Markov jump cyber–physical systems (S-MJCPSs) with general uncertain transition rates, quantization, actuator faults, denial-of-service (DoS) attacks and disturbances. In particular, a mode-dependent observer is developed to estimate the unmeasurable states of the considered system. Further, to minimize unnecessary data transmissions within the network channel, we have implemented a hybrid-triggered mechanism in which, the swap process between the time-triggered and the event-triggered mechanisms is governed by a Bernoulli distribution. Moreover, an observer-based hybrid-triggered quantized reliable controller is devised by utilizing the state estimation information obtained from the observer, which assists the S-MJCPSs to achieve primary intent of this study. Subsequently, the control input signals are quantized before being transmitted into the actuator due to the limited capacity of the data transmission medium. Concurrently, periodic DoS jamming attacks are taken into consideration, which have a significant impact on control performances. A set of adequate criteria is established in the context of linear matrix inequalities by employing the mode-dependent time-varying piecewise Lyapunov-Krasovskii functional and the integral inequalities, guaranteeing that the undertaken system accomplishes the global exponential stability and meet a specific H∞ performance level. Following that, by means of the deduced adequate criteria, the values of the controller and observer gain are computed. At last, the efficacy and applicability of the derived theoretical findings are demonstrated through two practical examples.

DNA-DISK: Automated end-to-end data storage via enzymatic single-nucleotide DNA synthesis and sequencing on digital microfluidics

In the age of information explosion, the exponential growth of digital data far exceeds the capacity of current mainstream storage media. DNA is emerging as a promising alternative due to its higher storage density, longer retention time, and lower power consumption. To date, commercially mature DNA synthesis and sequencing technologies allow for writing and reading of information on DNA with customization and convenience at the research level. However, under the disconnected and nonspecialized mode, DNA data storage encounters practical challenges, including susceptibility to errors, long storage latency, resource-intensive requirements, and elevated information security risks. Herein, we introduce a platform named DNA-DISK that seamlessly streamlined DNA synthesis, storage, and sequencing on digital microfluidics coupled with a tabletop device for automated end-to-end information storage. The single-nucleotide enzymatic DNA synthesis with biocapping strategy is utilized, offering an ecofriendly and cost-effective approach for data writing. A DNA encapsulation using thermo-responsive agarose is developed for on-chip solidification, not only eliminating data clutter but also preventing DNA degradation. Pyrosequencing is employed for in situ and accurate data reading. As a proof of concept, DNA-DISK successfully stored and retrieved a musical sheet file (228 bits) with lower write-to-read latency (4.4 min of latency per bit) as well as superior automation compared to other platforms, demonstrating its potential to evolve into a DNA Hard Disk Drive in the future.

Study on the Function of Social Media in Rural Health Communication in the Context of Media Convergence

In today's era, the rapid development of Internet technology is driving profound changes in the media landscape. Media convergence, an irreversible development trend, is penetrating into multiple dimensions such as form, technology, platform, market, organization and users. In the all-media era, the deep integration of communities, neighborhoods, regions and cultures is having a profound impact on China's media ecosystem. With the advent of the network era, health communication is facing unprecedented new opportunities and challenges. The application of advanced technologies such as algorithms and cloud computing has provided a brand new way to popularize health knowledge. This not only makes the dissemination of health information more efficient, but also allows more people to access health-related knowledge conveniently. However, in China's rural areas, health communication still faces many problems. The China New Media Development Report reveals in detail the current situation of rural health communication in terms of creation, content, dissemination, and influence, pointing out problems such as lack of subject, insufficient traffic, and insufficient media capacity. The report emphasizes that the construction of health culture is of great significance to rural revitalization. This study aims to promote the development of rural health communication, so that the dividends of technology can truly benefit the countryside and improve the health of rural residents. To this end, we need to actively explore and practice to find effective solutions to promote the progress of rural health communication in China.

Downflow and upflow sand filtration for removing turbid particles with diverse morphological and surface-charge characteristics: Comparisons of filtered water quality and head loss distribution

Besides the physicochemical characteristics (e.g., size, structure, charge nature, etc.) of turbid particles, the filtration flow direction may affect their migration and adhesion behaviors inside the filtration unit. Unfortunately, there has been a lack of research regarding the combined effects of these above factors on filtered water quality and head loss development during filtration. In this study, different turbid particles were prepared by flocculating water samples containing kaolin and humic acid. Filtration experimental results of these flocculated waters revealed that downflow and upflow filtration modes had different durations of effective filtration under identical PAC-dosage cases, and upflow filtration led to faster increases in filtered water turbidity at the breakthrough stage compared to downflow filtration. During 180-min downflow filtration, the average size of residual turbid particles increased, but this did not occur in upflow filtration. Furthermore, differently from downflow filtration, upflow filtration had a more uniform distribution of head loss across all filter layers. The ease of backwashing differed between the two filtration modes, reflected by the different times required for reaching a relatively stable turbidity during 10-min backwashing. Lastly, based on SEM, FTIR and XPS analyses for characterizing the coagulated particle surface morphology, element composition, and functional groups, a series of conceptual models for particle removal by downflow and upflow filtrations were developed to clarify the influencing mechanisms of different turbid particles on filtration. It highlighted the advantages of upflow filtration, including improved distribution of flow resistance, better removal of larger-sized turbid particles, and enhanced pollutant-holding capacity of the filter media.

INFLUENCE OF CHANGING PORTRAYALS OF WOMEN IN HINDI CINEMA ON YOUTH’S PROGRESSIVE GENDER ATTITUDES

This research paper examines the impact of evolving portrayals of women in Hindi cinema on the progressive gender attitudes of contemporary youth. In recent decades, Hindi cinema has increasingly shifted from portraying women primarily in conventional and submissive positions to presenting them in more forward-thinking and active roles. The objective of this study is to examine the impact of these alterations in cinematic portrayals on the perceptions and attitudes of young individuals towards gender equality. Through the use of a mixed-methods methodology including quantitative surveys and qualitative interviews, this study examines the relationship between film depictions and changes in gender attitudes among young people. Empirical evidence suggests that favourable depictions of women in contemporary Hindi film are linked to more progressive gender perspectives among young people, underscoring the capacity of media to influence society standards and behaviours.

A novel high‐impedance neutral grounding method for medium‐ or large‐size hydroelectric generators

AbstractAs the capacity of medium or large hydroelectric generators increases, conventional grounding methods face challenges in effectively limiting single‐phase to earth fault current and neutral displacement voltage within acceptable range. Excessive fault current and neutral displacement voltage pose threats to the stability and safety of power generation and transmission systems. Inherent design deficiencies in conventional grounding methods lead to failures in meeting fault current and voltage requirements. To address this, this paper proposes a novel grounding method utilizing high impedance to restrict excessive fault current and neutral displacement voltage. The method minimizes both fault current and neutral displacement voltage by optimally selecting device parameters through minimal iterative trials. Additionally, a novel indicator is introduced to evaluate the effectiveness of grounding method by monitoring changes in neutral displacement voltage. The method is tested through theoretical calculation and field experiments, successfully implemented in large‐size hydroelectric generator.

A Study of the Role of Mass Media in the Development of Society in Sudan: A Case Study

Abstract: The broad communications assumes a vital part in shaping social orders around the world, impacting social standards, spreading data, and encouraging financial turn of events. In Sudan, a country with a rich social legacy and a background marked by political unrest, the job of broad communications turns out to be considerably more critical. This theoretical digs into the diverse commitments of broad communications to the advancement of Sudanese society. Broad communications fills in as an imperative stage for data scattering, offering residents admittance to news, current issues, and instructive substance (Adam, A. (2018). In a different and geologically scattered country like Sudan, where ignorance rates stay high and admittance to formal training is restricted, broad communications overcomes any barrier in information dispersal. Through papers, radio, TV, and progressively advanced stages, residents gain consciousness of public arrangements, formative drives, wellbeing efforts, and socio-widespread developments. Writers and media specialists frequently assume an essential part in uncovering debasement, unfairness, and common liberties infringement, in this way considering specialists responsible and driving cultural advancement. The job of broad communications in Sudan isn't without challenges. Restriction, government control, and administrative limitations frequently thwart media opportunity and pluralism, smothering the variety of perspectives and hindering the media's capacity to satisfy its formative job successfully (Khalil, A. M. (2017). Moreover. In any case, tending to the difficulties of media opportunity, access, and pluralism is basic to bridling the maximum capacity of broad communications in driving feasible turn of events and cultural advancement in Sudan.

An improved convolutional neural network for predicting porous media permeability from rock thin sections

Permeability prediction is a crucial aspect of investigating fluid flow capacity in porous media, and rapidly predicting the permeability of rock thin sections aids in reservoir assessment. In recent years, significant progress has been made regarding the use of deep learning for predicting porous media permeability, effectively overcoming the limitations associated with time-consuming conventional permeability determination methods. To address the issues of low prediction accuracy and insufficient generalization capability of previous permeability prediction models, this study proposes an improved convolutional neural network for porous media permeability and applies it to predict the permeability of rock thin sections. Given the difficulty of obtaining a large amount of rock thin section data, we synthetically generated 1000 binary images of porous media and calculated the corresponding permeability labels using computational fluid dynamics. These data were used as foundational data for training the model. The proposed model achieved accurate and efficient permeability prediction of porous media with a correlation of 0.9667 on testing set. Simultaneously, we employed class activation mapping technology to visualize the permeability prediction process of the neural network, thereby elucidating the working principles of the neural network during porous media permeability prediction. Subsequently, based on an optimally pretrained neural network, transfer learning was utilized to predict the permeability of rock thin sections, which achieved a correlation of 0.9032. Our study extends the rock thin section applications and provides technical support for reservoir evaluation.

Theoretical evaluation of a hybrid buoyancy-compressed air energy storage system

Energy storage plays a pivotal role in the emerging green economy. This study, for the first time, presents the theoretical evaluation of a buoyancy power generator combining with the compressed air energy storage (CAES-BPG) system. A theoretical model that satisfies conservation laws and does not involve any adjustable parameters is developed for the calculation of system efficiency and power generation capacity. To accurately predict drag acting on the buoy, the low Reynolds number κ-ω SST model with a locally refined mesh (y+~1) is applied to fully resolve the viscosity affected regions including the viscous sublayers, whilst the surrounding flow is modelled by LES. The refined mesh moves passively with the buoy and does not change, whilst mesh in other regions undergoes smoothing and remeshing to accommodate the buoy's motion. Correlations of drag coefficients are then developed as a function of buoy shape, Reynolds number, and vessel-to-buoy size ratio. The aerofoil shape yielded a substantially smaller drag coefficient compared to the square, hex, and bullet shapes. System efficiency showed independency on buoy volume and shell material but decreased as the water level in the vessel increased, reaching 64 % for a water level of 1.5 m. Similarly, as the water level increased, the system output power decreased. The output power increased as the buoy volume increased, reaching ~22 kW for a buoy volume of 2 m3 at a water level of 1.5 m. This CAES-BPG system is highly automatic and fully green, and can operate continuously once compressed air is connected, showing great potential for implementation as an energy storage / utilisation system of small to medium capacities.

Flow-Independent Thermal Conductivity and Volumetric Heat Capacity Measurement of Pure Gases and Binary Gas Mixtures Using a Single Heated Wire.

Among the different techniques for monitoring the flow rate of various fluids, thermal flow sensors stand out for their straightforward measurement technique. However, the main drawback of these types of sensors is their dependency on the thermal properties of the medium, i.e., thermal conductivity (k), and volumetric heat capacity (ρcp). They require calibration whenever the fluid in the system changes. In this paper, we present a single hot wire suspended above a V-groove cavity that is used to measure k and ρcp through DC and AC excitation for both pure gases and binary gas mixtures, respectively. The unique characteristic of the proposed sensor is its independence of the flow velocity, which makes it possible to detect the medium properties while the fluid flows over the sensor chip. The measured error due to fluctuations in flow velocity is less than ±0.5% for all test gases except for He, where it is ±6% due to the limitations of the measurement setup. The working principle and measurement results are discussed.

Experimental study on the punching failure model of soft red rock subgrade by BPT-BVM methods and it’s assessment of the load bearing capacity

The recommended bearing capacity of medium weathering mudstone foundation is less than the capacity of the rock structure to withstand loads in Southwest China. A comprehensive failure characterization of medium weathering mudstone in Chengdu has been performed including bearing plate test (BPT), binocular vision measurement (BVM) test, uniaxial compressive strength test, trial trench test of shallow rock surface and 3D imaging in this paper. Failure behavior of rock has been modeled with 3D imaging algorithm that utilizes Zhang’s calibration method in BVM system combination with trial trench test of shallow rock surface. The bearing capacity of medium weathering mudstone foundation were extracted from uniaxial experiments and BPT-BVM test by fitting relevant material properties to the data. The results revealed that: Bearing capacity of medium weathering mudstone of layered isotropic in Chengdu is undervalued. Specifically, the characteristic load carrying value is in the range 1500–2500 kP, that is 50% higher than in the local standard system. Failure process is different from Hoek–Brown Failure Criterion, presenting a wave peak transfer phenomenon of the increment displacement into the distance. Thus, it can be reduced to that of punching failures for thin bedded structures of Moudstone foundations. Compressive strength of soft rock proves to be main factor limiting the bearing capacity, a clear correlation between the uniaxial compressive strength reduction coefficient and the bearing capacity has been used to establish, leading to the proposal of a load bearing capacity prediction model.

Experimental study on a compact solar driven two-stage humidification-dehumidification desalination system with shared dehumidifier

The low-cost and low-grade solar driven humidification-dehumidification desalination is considered a promising process for small and medium capacity freshwater production. Nevertheless, the enhancement of the unit volume water production rate is hindered by the disparity in mass transfer coefficient and the incongruity between heat and mass flow rate in the humidification and dehumidification process. This paper proposes a compact solar driven two-stage humidification-dehumidification desalination system with shared dehumidifier. It contains two humidifiers and a dehumidifier, wherein the dehumidifier is stacked between the vertically placed humidifiers. The circulating air is humidified by hot seawater in the top and bottom humidifiers respectively, and then goes to the middle dehumidifier to condense via a freshwater absorption process. Its design scheme and operating principle are introduced and a mathematical model describing its internal energy and mass flow process is established. An experimental setup with compound parabolic concentrator areas of 6 m2 is developed, and a sequence of experiments is carried out. The results indicate that its freshwater productivity can reach 29.6 kg/h with a gained output ratio of 0.84 when the feed seawater temperature is 80 ℃. Due to its compact structure, the freshwater production per volume unit per day reaches up to 224.1 kg/(day⋅m3). This work may promote the development of solar humidification and dehumidification systems towards low cost and high efficiency.