Variations In Environmental Parameters Research Articles

Environmental control of interannual and seasonal variability in dinoflagellate cyst export flux over 18 years in the Cape Blanc upwelling region (Mauritania)

The increasing threat of anthropogenic environment and climate change amplifies the urgency to investigate the effect of these changes on marine ecosystems. We provide information about the export flux of organic-walled dinoflagellate cysts between 2003 and 2020 in the upwelling ecosystem off Cape Blanc (Mauritania), one of the world’s most productive regions. We compared the cyst export flux with variability in environmental parameters, such as wind speed, wind direction, dust emission, sea surface temperature (SST), SST difference between trap location and open ocean (SSTa), and chlorophyll-a concentration. This information is valuable to determine the ecological signal of dinoflagellate cysts that could be applied in recent and paleo records. The total export production of dinoflagellate cysts fluctuated between 0 - 1.18 x 105 cysts m-2 d-1 for the heterotrophs and 0 - 1.06 x 104 cysts m-2 d-1 for the photo-/mixotrophs. The export productions of both groups were in line with changes in upwelling intensity, which in most years, intensified in spring - summer. Dinoflagellate cyst association was dominated by heterotrophic taxa that formed an average of 94% of the association throughout the sediment trap record. A strong interannual variation in the cyst export fluxes, as well as the association composition was observed in the record. We identified five groups that showed comparable variability in export production with changes in environmental conditions: (1) maximal upwelling; Echinidinium delicatum/granulatum, E. transparantum/zonneveldiae, Echinidinium spp., Trinovantedinium spp., and Protoperidinium latidorsale, (2) combined maximal upwelling and dust input; Archaeperidinium spp., P. americanum, P. stellatum, and P. subinerme, (3) upwelling relaxation; Gymnodinium spp. and L. polyedra, (4) warm surface waters; Bitectatodinium spongium and Protoceratium reticulatum, (5) species with no specific relationship to the studied environmental variables; Brigantedinium spp., E. aculeatum, Impagidinium aculeatum, P. conicum, P. monospinum, Pentapharsodinium dalei, and Spiniferites spp. The sediment trap record documented a gradual shift in the cyst taxa association that co-occurred with the gradual increase of Saharan dust input to the region, notably after 2008. The cyst association contained five photo-/mixotrophic taxa that were formed by potentially toxic dinoflagellates. The latter could cause threats to the socio-economy of coastal communities.

Smart Hydroponic Systems: Optimizing Nutrient Levels with IoT Connectivity

Maintaining precise nutrient levels is essential for the thriving success of hydroponic systems. This comprehensive study delves into the intricate interplay of climatic conditions and nutrients, meticulously analysing various parameters like Total Dissolved Solids (TDS), pH, and electrical conductivity (EC) within a sophisticated smart hydroponic vertical Nutrient Film Technique (NFT) setup designed for leafy greens. The innovative system integrates a wireless sensor network and Internet of Things (IoT) connectivity, employing ESP32 microcontrollers as the primary unit alongside complementary hardware components for continuous and real-time monitoring of critical nutrient parameters. The investigation delves into the dynamic relationship between environmental factors and the growth patterns of spinach plants. Through a thorough examination of the extensive dataset gathered via deployed sensors, the study unveils variations in environmental parameters throughout various stages of plant development, including germination and root establishment. The study aims to elucidate the significance of each parameter in optimizing plant growth in hydroponic environments by analysing data associations. Results show higher Total Dissolved Solids (TDS) values correlate with better plant growth, while reduced pH levels harm plants. These findings are crucial for interpreting disease symptoms, aiding farmers in identifying issues early and optimizing yields. Understanding how nutrient values affect plant health enables proactive problem-solving. This research provides valuable insights into smart hydroponic systems, informing precision agriculture decisions.

Smart Hydroponic Systems: Optimizing Nutrient Levels with IoT Connectivity

Maintaining precise nutrient levels is essential for the thriving success of hydroponic systems. This comprehensive study delves into the intricate interplay of climatic conditions and nutrients, meticulously analysing various parameters like Total Dissolved Solids (TDS), pH, and electrical conductivity (EC) within a sophisticated smart hydroponic vertical Nutrient Film Technique (NFT) setup designed for leafy greens. The innovative system integrates a wireless sensor network and Internet of Things (IoT) connectivity, employing ESP32 microcontrollers as the primary unit alongside complementary hardware components for continuous and real-time monitoring of critical nutrient parameters. The investigation delves into the dynamic relationship between environmental factors and the growth patterns of spinach plants. Through a thorough examination of the extensive dataset gathered via deployed sensors, the study unveils variations in environmental parameters throughout various stages of plant development, including germination and root establishment. The study aims to elucidate the significance of each parameter in optimizing plant growth in hydroponic environments by analysing data associations. Results show higher Total Dissolved Solids (TDS) values correlate with better plant growth, while reduced pH levels harm plants. These findings are crucial for interpreting disease symptoms, aiding farmers in identifying issues early and optimizing yields. Understanding how nutrient values affect plant health enables proactive problem-solving. This research provides valuable insights into smart hydroponic systems, informing precision agriculture decisions.

Spatiotemporal dynamics of bacterioplankton communities in the estuaries of two differently contaminated coastal areas: Composition, driving factors and ecological process

Seasonal variations of environmental parameters usually lead to considerable changes in microbial communities. Nevertheless, the specific response patterns of these communities in coastal areas subjected to different levels of contamination remain unclear. Our results revealed notable fluctuations in the bacterioplankton community both seasonally and spatially, with seasonal variations being particularly significant. The diversity and composition of bacterioplankton communities in the estuaries varied significantly across seasons and between seas. Some bacterial phyla that were highly abundant in the dry season (e.g., Patescibacteria and Epsilonbacteraeota) were almost absent in the wet season. Furthermore, the network analysis revealed that the bacterioplankton networks were more complex during the wet season than in the dry season. In the wet season, the estuarine bacterioplankton network in the Yellow Sea region was more complex and stable, while the opposite was true in the dry season. According to the neutral community model, stochastic processes played a more significant role in the formation of bacterioplankton communities during the wet season than during the dry season. Estuarine bacterioplankton communities in the Yellow Sea region were more affected by stochastic processes compared to those in the Bohai Sea. In summary, in the estuaries of two differently contaminated coastal areas, the seasonal increase in nutrient levels enhanced the deterministic processes and network complexity of the bacterioplankton communities.

An energy-efficient design of ternary SRAM using GNRFETs

ABSTRACT The primary requirement of internet-of-things (IoT) applications is to have an energy-efficient design that extends the battery life for long-term operation. To achieve energy efficiency, one can employ multiple-valued logic (MVL) instead of binary logic and utilise graphene nanoribbon field-effect transistors (GNRFETs) as variable-threshold voltage (V th ) capable devices. The implementation of an MVL system enhances data transferability and reduces the number of interconnections, resulting in improved energy consumption compared to a binary system. In such systems, static random access memory (SRAM), which serves as a crucial component of very large-scale integrated (VLSI) chips, dominates energy consumption. This research paper introduces an energy-efficient ternary SRAM using GNRFETs. We propose a standard ternary inverter based on GNRFET devices, which serves as the fundamental building block of a storage cell. Simulation results conducted on a 32-nm GNRFET with a 0.9 V supply voltage demonstrate that the proposed design achieves energy consumption improvements ranging from 46.39% to 98.16% compared to the most recent ternary SRAMs. Furthermore, the SRAM cell is evaluated under various processes and environmental parameter variations.

Spatial variability in herbaceous plant phenology is mostly explained by variability in temperature but also by photoperiod and functional traits.

Whereas temporal variability of plant phenology in response to climate change has already been well studied, the spatial variability of phenology is not well understood. Given that phenological shifts may affect biotic interactions, there is a need to investigate how the variability in environmental factors relates to the spatial variability in herbaceous species' phenology by at the same time considering their functional traits to predict their general and species-specific responses to future climate change. In this project, we analysed phenology records of 148 herbaceous species, which were observed for a single year by the PhenObs network in 15 botanical gardens. For each species, we characterised the spatial variability in six different phenological stages across gardens. We used boosted regression trees to link these variabilities in phenology to the variability in environmental parameters (temperature, latitude and local habitat conditions) as well as species traits (seed mass, vegetative height, specific leaf area and temporal niche) hypothesised to be related to phenology variability. We found that spatial variability in the phenology of herbaceous species was mainly driven by the variability in temperature but also photoperiod was an important driving factor for some phenological stages. In addition, we found that early-flowering and less competitive species characterised by small specific leaf area and vegetative height were more variable in their phenology. Our findings contribute to the field of phenology by showing that besides temperature, photoperiod and functional traits are important to be included when spatial variability of herbaceous species is investigated.

Silver nanoparticle doped laser-induced graphene fabrication methodology affects silver nanoparticle size, distribution, biological and electrochemical properties

Three fabrication methods for metal-doped laser-induced graphene (LIG) are compared resulting in stable nanoparticles embedded within LIG. Variable nanoparticle size, distribution, antibacterial and electrochemical properties were observed.

(Invited) Electrochemical Characterization of Catalyst/Ionomer Interfaces

Electrochemical energy conversion devices such as polymer-electrolyte fuel cells, water-splitting or carbon dioxide reduction electrolyzers, utilize ionically-conductive polymers (ionomers) in their electrode structure where an ionomer forms interfaces with the catalysts. The ionomers exist as nanometer-thick film to cover the catalyst particles and act as a binder while enabling the transport of active species necessary for the reactions. While the nature of species and operational environment differs across these devices, their overall efficiency and performance is influenced by the electrode architecture, where the interfaces and interactions between the ionomers and catalysts play an important role. In hydrogen technologies, for example, ionomer thin films bind the catalyst sites and carbon supports to facilitate transport of ionic (e.g. protons), liquid (water) and gaseous (e.g., oxygen) species under a nano-confined environment. Such confinement effects not only change the ionomer structure and properties, usually with a tendency to increase transport resistances, but also amplify the impact of the electrocatalyst-ionomer interactions in the electrodes, thereby reducing the catalyst activity. Thus, understanding the behavior of nano-confined ionomers and their interactions with the catalyst surfaces is key for mitigating the transport resistances in catalyst ionomers and improving the electrode performance and cell efficiency.This talk will provide insights into electrochemical characterization of catalyst ionomers by focusing on varying chemistries of perfluorosulfonated cation-exchange ionomers with additional examples of anion-exchange ionomers for emerging technologies. The hydration and transport properties of proton-exchange catalyst-ionomers will be examined with the effects of chemistry, processing and thickness (degree of confinement), along with their impact on the morphological changes governing the film function. Through a systematic variation of material chemistries and environmental parameters, primary factors impacting the structure-property relationship of catalyst ionomers are described along with a discussion of secondary factors altering the cation-anion interactions. Then, the interplay between the effects of chemistry and ion exchange (capacity) on modifying the transport function and the strength of ionomer-catalyst interactions will be presented. The results will be collated to elucidate the underlying origins of the transport resistances occurring in electrodes, and to develop materials and processing strategies for their mitigation for improved performance and efficiency in electrochemical energy devices.

ASSESSING THE RELATION BETWEEN LAND USE / LAND COVER CHANGES AND ENVIRONMENTAL PARAMETERS FOR CHENNAI CITY, TAMIL NADU: A REMOTE SENSING AND GIS APPROACH

Abstract. Land use land cover changes in coastal regions are prone to many factors like rapid urbanization and industrialization, tourism, and tideline changes etc. Chennai city, a coastal city of TamilNadu, India has witnessed tremendous changes in land use land cover over the past two decades due to rapid urbanization and industrialization. Remote sensing and GIS technologies can efficiently help in analyzing these changes. In this study, changes in land use land cover patterns of Chennai city from 2005 to 2016 were assessed using IRS P6 LISS III remotely sensed satellite images. Post classification comparison-based change detection method was used to identify the changes in LU/LC. The study shows an increase in compact built-up and industrial areas by 15.36 % and 7.22 % respectively and a decrease in agricultural land, wetlands, and water bodies by 3.66%, 1.73%, and 5.24% respectively over the past decade. The obtained LU/LC changes were correlated with environmental parameters like Land surface temperature (LST), annual average rainfall and average groundwater level to establish a relation. Observations have shown that the temperature in Chennai metropolitan city has increased by 6̊c from 2005 to 2016 and the rainfall has reduced by 100mm from 2005 to 2016. This study demonstrated the relation between LU/LC changes over the past decade and the variations in environmental parameters like increased LST, reduced rainfall and groundwater.

Feature-Based Place Recognition Using Forward-Looking Sonar

Some structures in the harbour environment need to be inspected regularly. However, these scenarios present a major challenge for the accurate estimation of a vehicle’s position and subsequent recognition of similar images. In these scenarios, visibility can be poor, making place recognition a difficult task as the visual appearance of a local feature can be compromised. Under these operating conditions, imaging sonars are a promising solution. The quality of the captured images is affected by some factors but they do not suffer from haze, which is an advantage. Therefore, a purely acoustic approach for unsupervised recognition of similar images based on forward-looking sonar (FLS) data is proposed to solve the perception problems in harbour facilities. To simplify the variation of environment parameters and sensor configurations, and given the need for online data for these applications, a harbour scenario was recreated using the Stonefish simulator. Therefore, experiments were conducted with preconfigured user trajectories to simulate inspections in the vicinity of structures. The place recognition approach performs better than the results obtained from optical images. The proposed method provides a good compromise in terms of distinctiveness, achieving 87.5% recall considering appropriate constraints and assumptions for this task given its impact on navigation success. That is, it is based on a similarity threshold of 0.3 and 12 consistent features to consider only effective loops. The behaviour of FLS is the same regardless of the environment conditions and thus this work opens new horizons for the use of these sensors as a great aid for underwater perception, namely, to avoid degradation of navigation performance in muddy conditions.

Effect of environmental drivers of fish assemblage and diversity patterns in temporal scale in Mongra Reservoir: A case study from one of the tributaries of Mahanadi Basin, Central India

AbstractInfluence of seasonal variations in environmental parameters on fish assemblage and species diversity patterns was studied in a tropical reservoir of Central India during March 2021 to February 2022. A total of 41 species belonging to 7 orders, 15 families and 29 genera were recorded with highest diversity during post‐monsoon season compared to the pre‐monsoon season and monsoon season. The fish abundance similarity between the monsoon and post‐monsoon reached a maximum of 89%. Seasonal variations in the mean species abundance, Simpson dominance index, Shannon diversity index, Pielou's evenness index and Margalef's richness index were determined. One‐way ANOVA revealed a significant difference (P < 0.05) at the temporal scale. There was a significant seasonal difference in species abundance (P = 0.0006) and evenness index (P = 0.02) among the diversity indices. During the study period, three ‘vulnerable’ species, three ‘near threatened’ species and two ‘endangered’ species were caught. Carnivore dominance was evident throughout the year in the trophic guild of fishes. The Pearson correlation test revealed that water pH, dissolved oxygen, sediment organic carbon and clay percentage were positively correlated to all four diversity indices. Simpson and Margalef species richness diversity indices were positively correlated to sediment pH. Fish abundance was positively associated with sediment pH, silt, phosphorus and nitrogen content. Canonical correspondence analysis was used to investigate the relationships between fish assemblages and environmental conditions. Among the 19 physicochemical parameters, nine (dissolved oxygen, total dissolved solids, conductivity, transparency, hardness, phosphate and chlorophyll‐a, sediment nitrogen and phosphorus) characteristics were shown to be statistically significant (P < 0.05) in determining fish diversity. Dissolved oxygen, total dissolved solids, conductivity, transparency, hardness, phosphate and chlorophyll‐a of water and sediment nitrogen and phosphorus qualities were the key factors for the species abundance. The reservoir boasts a diverse fish population that allows multi‐species fishing and generates revenue for numerous local fishers. Fish habitats should be protected in order to maintain diversity and long‐term ecological benefits.

A virtual sensor network for pressure distribution inside a multi-zone building based on spatial adjacency relationships and multivariate adaptive regression spline

Airflows within multi-zone buildings cause variations in environmental parameters both vertically and horizontally. Although it is difficult to monitor the airflows through existing sensors, pressure monitoring allows the identification of airflows, since airflows across zones are induced by pressure differences. This study proposes a data-driven method for establishing a virtual pressure sensor network within a multi-zone building. Three scenarios with various sample sizes are applied to evaluate their impacts on the analyzed results, and scenario 3 is identified as the most suitable database for creating a virtual sensor network. The single-sided or multi-sided spatial adjacency relationships are determined for each zone, and the MARS model is then applied to develop the relationships among the variables, with key physical sensors designated by the frequency analysis of independent variables. The final sensor network comprises four key physical sensors, thirteen direct virtual sensors, and five indirect virtual sensors. All virtual sensors can achieve excellent predicted results with high R2 values and low MAE and RMSE, with mean values of 0.997 Pa and 1.269 Pa, respectively. Notably, the difference in accuracy between direct and indirect virtual sensors is influenced by spatial adjacency relationships. This study demonstrates a reliable virtual sensor network for predicting pressure variations and provides a reference for the identification of airflows and the efficient adjustment of HVAC systems.

Ecological assessment of a subtropical floodplain wetland of the Ganga basin in the context of changing climate using GIS tools

Abstract Climate change associated with anthropogenic stressors are considered the main threat to the tropical wetlands, resulting in reduced water connection followed by a decline in ecological functions. This article presents a systemic approach to assess the present ecological status of a tropical floodplain wetland concerning the fisheries and associated ecosystem services. The analysis of historic climatic data indicated significant change (increasing average annual air temperature, R2 = 0.098; decreasing total annual rainfall, R2 = 0.042). In addition, a significant reduction in the wetland area was also observed. Altogether, 45 fish species were reported in the studied wetland, of which 2 are listed as endangered and 7 are near threatened. The present study demonstrated the variation of the important fisheries-related environment and nutrient parameters of the wetland through the geographic information system (GIS)-based spatial distribution map for the reader's digest. It has been found that the provisioning ecosystem services are higher in number (n=9) followed by supporting (n=6), regulating (n=4), and cultural (n=2) ecosystem services. Finally, we have discussed some important case-specific sustainable climate-smart adaptation and mitigation approaches to strengthen the resilience and adaptive capacity of fishers.

Impact of Variation in Environmental Parameters on Abundance of Paracalanidae (Calanoida: Copepoda) from the Tropical Coast of India, Bay of Bengal

Impact of Variation in Environmental Parameters on Abundance of Paracalanidae (Calanoida: Copepoda) from the Tropical Coast of India, Bay of Bengal

Shifts in species dominance related to spatial assemblages and variation in environmental parameters in a tropical mangrove estuary

A shift in species dominance in the mangrove microalgae community in Cross River Estuary System (CRES), Nigeria, was carried out during the wet season to highlight the microalgae structure, identify potential indicators, and evaluate the water quality variation. Plankton samples were collected at sixteen selected sampling sites along the river. Diatoms showed the highest number of species (240 species), contributing more than 70% of the total microalgae abundance. Cluster analysis of the microalgae community delimits the CRES into three sections; upper (UCRS), middle (MCRS), and lower (LCRS) communities. The spatial shift in the microalgae community showed that the green algae (Eudorina elegans and Hylotheca dissiliens) dominated the UCRS communities, while diatoms dominated the MCRS (Polymyxus coronalis and Actinocyclus normanii) and LCRS (A. normanii and A. octonarius). The principal component analysis showed that the UCRS was influenced by turbidity and nitrate, while the MCRS and LCRS were characterized by phosphate, electrical conductivity, and salinity/total dissolved solids. The similarity percentage (SIMPER) analysis showed that Surirella tenera and Hylotheca dissiliens contributed >3.5% inter site dissimilarity between the UCRS and LCRS microalgae community. The redundancy analysis revealed that some microalgae species such as Odontella mobiliensis, Coscinodiscopsis jonesiana, A. normanii, and A. octonarius responded positively to salinity change and ammonia concentration in the estuary, while S. tenera, P. coronalis, Bacillaria paxilifer, Navicula transitans, Cyclotella meneghiniana, Humidophila contenta, Melosira granulata, Aulacoseira herzogii, Eudorina elegans, H. dissiliens, Mougeotia sp., and Dinobryon sertularia responded positively to turbidity, nitrate, and phosphate concentration. This study illustrates that CRES inhabit rich biodiversity of microalgae which some taxa could be used as indicators of the environmental changes in marine waters.

Slow growing bacteria survive bacteriophage in isolation

The interactions between bacteria and bacteriophage have important roles in the global ecosystem; in turn changes in environmental parameters affect the interactions between bacteria and phage. However, there is a lack of knowledge on whether clonal bacterial populations harbour different phenotypes that respond to phage in distinct ways and whether the abundance of such phenotypes within bacterial populations is affected by variations in environmental parameters. Here we study the impact of variations in nutrient availability, bacterial growth rate and phage abundance on the interactions between the phage T4 and individual Escherichia coli cells confined in spatial refuges. Surprisingly, we found that fast growing bacteria survive together with all of their clonal kin cells, whereas slow growing bacteria survive in isolation. We also discovered that the number of bacteria that survive in isolation decreases at increasing phage doses possibly due to lysis inhibition in the presence of secondary adsorptions. We further show that these changes in the phenotypic composition of the E. coli population have important consequences on the bacterial and phage population dynamics and should therefore be considered when investigating bacteria-phage interactions in ecological, health or food production settings in structured environments.

Evaluation of Rodent Diet Stability when Stored in Conditions that Diverge from Guide Parameters.

An essential aspect of animal resource programs is the storage and provision of food for a variety of species. Environmentalparameters for feed storage conditions (temperature less than 70 °F; relative humidity less than 50%) are recommended in theGuide for the Care and Use of Laboratory Animals, along with aspects of nutrition such as palatability, vermin-control measures,diet quality, and integrity of feed bags. After receiving a suggestion for improvement for environmental conditions in2 feed storage locations during an AAALAC accreditation visit, we hypothesized that the packaging of contemporary rodentfeed could sustain wider environmental variations in temperature and humidity without adverse impact on integrityand palatability. This study evaluated representative feed storage sites across campus buildings to capture the variationin environmental conditions that are inherent to large and diverse animal care programs. Each test storage location held2 identical bags of feed (same type, lot, and expiration date) that were stored from June to September of 2021; some aspectsof the project were repeated during summer 2022 with a similar rodent feed. Baseline nutrients were analyzed from feedsamples collected at time 0 (control) and again after 1 and 3 mo of storage. The overall nutritional values measured in feed atthe end of the study were not significantly different from control values, regardless of test site and variation in environmentalparameters. Retinol (as a measure of Vitamin A) was the only component that decreased significantly; however, final retinollevels were consistently above those necessary for appropriate nutrition for mice. Our animal care program stakeholderswere briefed on the outcomes of this study with the intent to verify at future AAALAC site visits that our storage conditionsare adequate for maintaining the nutritional quality of packaged rodent feed.

Influence of environmental conditions on mass rearing parameters of tsetse flies at the Bobo-Dioulasso insectary (Burkina Faso): Retrospective study

With the goal of eradicating tsetse flies and trypanosomiasis in Africa, several control methods have been developed. One of this is the  biological control through the application of the sterile insect technique (SIT) as a part of an area-wide integrated pest management. This  method required the mass production of sterile males with a high competitiveness. The success of the tsetse mass rearing is  strongly linked to the rearing conditions. The objective of this study was to do a retrospective evaluation of the impact of ambient  conditions on the production performances of Glossina palpalis gambiensis at Insectary of Bobo Dioulasso. Data of productivity,  fecundity, adult emergence and environmental conditions (temperature and relative humidity) of the rearing rooms were recorded from  March to June 2020 and were analysed. The results showed a reduction of the normal pupae produced and the increase of soft pupae  during this period. In addition, the relative humidity has shown a significant positive correlation with the production of soft pupae,  whereas it had a significant negative correlation with the number of pupae produced per female per 10 days. However, the temperature  variation during the period of the data recording didn’t have any impact on the production parameters. Rearing rooms need a better    management to avoid large variations in environmental parameters.

The Fontanamare Discovery (Sardinia Coast, Italy), a Case of Underwater Corrosion of Bronze Coins

This study reports the analytical approach towards nine coins found in wreck A of Fontanamare for understanding the complex corrosion processes that take place in underwater conditions. Optical microscopy (OM) combined with micro-Raman (µ-Raman) spectroscopy, X-ray diffractometry (XRD), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM and EDS) were used to analyze the nature and the microstructure of the corrosion patina in comparison with the non-degraded state of coins. Three main types of corrosion patina based on copper, lead chloride, and carbonate were identified: black, white, and green, and the obtained results demonstrate the complex corrosion processes that take place in underwater conditions. To better understand the role played by different chemical and physical parameters in the corrosion of bronze artefacts in an underwater environment, this study attempts to understand the nature of the patinas on the coins in relation to the specific structural and environmental parameter variation.

Field measurement of environmental parameters in solar greenhouses and analysis of the application of passive ventilation

Solar greenhouses are passive agricultural facilities that can realize off-season production. The growth of crops in greenhouses is affected by various environmental parameters. Therefore, it is necessary to understand the variations of environmental parameters in solar greenhouses through field testing to improve their internal environment. Through field tests, it was found that the temperature variation in solar greenhouses was positively correlated with the change in solar radiation. When the top vent was opened, the minimum temperature in the greenhouse remained higher than 30 °C. The temperature gradient in the tall-plant greenhouse was twice that in the short-plant greenhouse. The relative humidity at the bottom of the tall-plant greenhouse remained greater than 65%. Top-vent opening for greenhouse ventilation is not conducive to the cooling and dehumidification of these relatively large sized greenhouses tested in this study. Passive ventilation via an integrated solar chimney and earth-air heat exchanger was applied in an experimental solar greenhouse. The results showed that when the passive ventilation was turned on, the indoor air temperature in the horizontal and vertical direction could be maintained in the range of 25 ∼ 28 °C and 25 ∼ 30 °C, respectively. The air temperature in the vertical direction had been decreased by approximately 3.5 to 6.5 °C. The passive ventilation effectively prevented continuous increases in indoor temperature, improved indoor air distribution and was conducive to the normal growth of crops.