خيارات البحث
النتائج 1 - 10 من 15
A review of physical, chemical, and biological green tide prevention methods in the Southern Yellow Sea
2022
Xia, Zhangyi | Yuan, Huanqing | Liu, Jinlin | Sun, Yuqing | Tong, Yichao | Zhao, Shuang | Xia, Jing | Li, Shuang | Hu, Meijuan | Cao, Jiaxing | Zhang, Jianheng | He, Peimin
Green tides dominated by Ulva prolifera have be present in the Southern Yellow Sea for 15 consecutive years. They not only damage the marine environment, but also cause economic losses to coastal cities. However, there is still no fully effective approach for preventing green tides. In this article, approaches for the prevention of U. prolifera taken over recent years are reviewed. They can be generally divided into physical, chemical, and biological approaches. Physical approaches have been used to control the overwhelming green macroalgae bloom and inhibit the germination of U. prolifera, including physical salvage approach, refrigeration net technology, improved farming methods and raft technology, and modified clay method. These approaches require significant labor and material resources. Many chemical reagents have been used to eliminate U. prolifera early germination and growth, such as oxidative algaecide, acid treatment, heavy metal compounds, antifouling coating, and alkaloids. Chemical approaches have high efficiency, high economic benefit, and simple operation. Presently, biological control approaches remain in the exploratory stage. The verification of pilot and large-scale experiment results in sea areas is lacking, including the application of large organisms and microorganisms to control U. prolifera, and some of the mechanisms have not been thoroughly studied. This article introduces the three types of approaches, and evaluates the advantages and disadvantages of different methods to facilitate the reduction of the green tide bloom scale in the Southern Yellow Sea.
اظهر المزيد [+] اقل [-]A novel intelligent strategy–based thermodynamic modeling and analysis of solar-assisted vapor absorption refrigeration system
2022
Kadyan, Harsh | Berwal, Anil Kumar | Mishra, Radhey Shyam
In recent times, solar energy has been utilized for refrigeration systems due to its efficiency and clean form of energy. Moreover, the evacuated tube collector (ETC)–assisted vapor absorption refrigeration system plays a significant role in the modern industrial world compared to the traditional electrical system. However, the conventional vapor absorption refrigeration system design is complex in nature and causes corrosion in the system. Therefore, in this research, novel Generalized Approximate Reasoning–Based Intelligent Control (GARIC) and Hybrid Ant Colony African Buffalo Optimization (HACABO) methods based on an ETC-linked 5-kW vapor absorption refrigeration system are proposed depending on lithium bromide-water (LiBr-H₂O). Primarily, the Haryana region’s solar radiation and weather parameters were taken over a year to simulate the ETC system. ETC collects the solar energy for the refrigeration cycle, and the efficiency of the ETC is estimated using the GARIC method as per the input of solar radiation, collector area, and used solar energy. Moreover, the efficiency of the ETC is optimized using the proposed HACABO method. The modified polynomial fits curved equation is utilized for performance analysis. The simulation model of the solar cooling absorption system is carried out in the MATLAB platform. The coefficient of performance (COP) rate of the absorption cycle has gained 0.82% with the help of HACABO. Compared to other recent associated models, the proposed model has maximized the COP in the finest range.
اظهر المزيد [+] اقل [-]Multi-objective cold chain logistic distribution center location based on carbon emission
2021
Li, Xinguang | Zhou, Kang
The issues of food safety and environmental protection are attracting more and more attention. Everyday, a large number of cold chain products are delivered from suppliers to customers. The cold chain products require refrigeration equipment in delivery and should be delivered to customers as soon as possible. Therefore, the challenge of reducing carbon emission and improving the customer satisfaction should be solved. This study presents the impact of carbon emission, customer satisfaction, construction cost, and operation cost on the location of cold chain logistics distribution center. A multi-objective location model for cold chain logistics distribution center considering carbon emission is established. The carbon emission equivalent cost model considers the dynamic carbon emission during transportation and the static carbon emission of the distribution center. The penalty cost under the time window is introduced into the penalty cost model of customer satisfaction, which represents a multi-objective mixed-integer linear programming problem. A non-dominated sorting genetic algorithm II (NSGA-II) is used to design the program through double-layer composite coding. NSGA-II uses a fast non-dominated sorting approach to reduce the computational complexity of non-dominated sorting. This algorithm uses the elitist control strategy, which does not need to share parameters and is more efficient in the multi-objective optimization process. The numerical results show that the proposed algorithm can generate appropriate Pareto solutions for all objectives.
اظهر المزيد [+] اقل [-]Comparison of different adsorption pairs based on zeotropic and azeotropic mixture refrigerants for solar adsorption ice maker
2021
Mostafa, Massaud | Ezzeldien, M. | Attalla, M. | Ghazaly, Nouby M. | Alrowaili, Z. A. | Hasaneen, M. F. | Shmroukh, Ahmed N.
One of the important ways to the efficiently use of low-grade thermal energy is the adsorption refrigeration technology. However, it has some drawbacks such as low specific cooling power and coefficient of performance, especially under using the conventional adsorption pairs. Therefore, new adsorption pairs are tested in solar adsorption ice-maker and compared with other conventional pairs data from open literature to find the tendency of improving the solar adsorption ice-maker performance. The experimental test rig has been built in Upper Egypt in Qena City. Four different new adsorption pairs of granular activated carbon/R-410A, granular activated carbon/R-511A, Maxsorb III/R-410A, and Maxsorb III/R-511A are used. It is demonstrated that Maxsorb III/R-511A pair based solar adsorption ice-maker produced the highest values for specific cooling power, coefficient of performance, and ice production per 1 kg of adsorbent of approximately 226.7 W/kgₐdₛ, 0.197, and 1.96 kg/kgₐdₛ, respectively. While granular activated carbon/R-410A based solar adsorption ice-maker produced the lowest values of ice production per 1 kg of adsorbent and coefficient of performance of 1.38 kg/kgₐdₛ and 0.104, respectively. Moreover, it can be concluded that the tested pairs are feasible to be used in solar adsorption ice-maker systems, especially in such hot climate of Upper Egypt for food and vaccine preservation and storage.
اظهر المزيد [+] اقل [-]Experimental investigation on solar-powered ejector refrigeration system integrated with different concentrators
2021
The objective of the work is to analyse and to improve the efficiency of solar-powered ejector refrigeration system integrated with flat-plate collector and Scheffler concentrator. The Scheffler concentrator of 2.7 m² and flat-plate collector of 5 m² collecting area are coupled with the storage tank of 15 l capacity. The developed system was designed for a potential replacement of conventional 1-ton room air conditioner with much reduced electrical energy consumption. The system was built based on two key subsystems namely ‘Scheffler concentrator-based vapour system’ and ‘ejector-based cooling system’. The pilot effort showed promising results with the probability of energy-saving potential as near 70 to 80% over conventional air conditioners.
اظهر المزيد [+] اقل [-]Magnetic properties of biogenic selenium nanomaterials
2021
Dixit, Rewati | Gupta, Anirudh | Jordan, Norbert | Zhou, Shengqiang | Schild, Dieter | Weiss, Stephan | Guillon, Emmanuel | Jain, Rohan | Lens, P. N. L. (Piet N. L.)
Bioreduction of selenium oxyanions to elemental selenium is ubiquitous; elucidating the properties of this biogenic elemental selenium (BioSe) is thus important to understand its environmental fate. In this study, the magnetic properties of biogenic elemental selenium nanospheres (BioSe-Nanospheres) and nanorods (BioSe-Nanorods) obtained via the reduction of selenium(IV) using anaerobic granular sludge taken from an upflow anaerobic sludge blanket (UASB) reactor treating paper and pulp wastewater were investigated. The study indicated that the BioSe nanomaterials have a strong paramagnetic contribution with some ferromagnetic component due to the incorporation of Fe(III) (high-spin and low-spin species) as indicated by electron paramagnetic resonance (EPR). The paramagnetism did not saturate up to 50,000 Oe at 5 K, and the hysteresis curve showed the coercivity of 100 Oe and magnetic moment saturation around 10 emu. X-ray photoelectron spectroscopy (XPS) and EPR evidenced the presence of Fe(III) in the nanomaterial. Signals for Fe(II) were observed neither in EPR nor in XPS ruling out its presence in the BioSe nanoparticles. Fe(III) being abundantly present in the sludge likely got entrapped in the extracellular polymeric substances (EPS) coating the biogenic nanomaterials. The presence of Fe(III) in BioSe nanomaterial increases the mobility of Fe(III) and may have an effect on phytoplankton growth in the environment. Furthermore, as supported by the literature, there is a potential to exploit the magnetic properties of BioSe nanomaterials in drug delivery systems as well as in space refrigeration.
اظهر المزيد [+] اقل [-]Vapour absorption refrigeration system for rural cold storage: a comparative study
2021
Value addition of agro products improves the livelihood opportunities for rural farmers. Cold Storage is one of the techniques to improve the shelf life of agro product. With the increase in the utilization of refrigeration and air cooling using vapour compression refrigeration technology, global warming and ozone depletion due to the refrigerants have also been increased. So, to overcome this problem, several restrictions were placed on the refrigerant by the United Nations Framework Convention on Climate Change (UNFCCC). There is no way to slow down the growth of this technology, so the focus should be shown on finding an alternative. Various studies have been carried out on an alternate refrigeration system. This paper attempts to study the power quality challenges in the conventional vapour compression system. A comparative analysis of vapour compression refrigeration (VCR) and vapour absorption refrigeration (VAR), power factor analysis and temperature measurement on both technologies has also been carried out and reported.
اظهر المزيد [+] اقل [-]Environmental friendly micro cold storage for last-mile Covid-19 vaccine logistics
2022
Nadimuthu, Lalith Pankaj Raj | Victor, Kirubakaran
Globally, vaccination plays a vital role in controlling the Covid-19 pandemic. However, the cold supply chain is essential for vaccine storage and logistics services. In a country like India, the last-mile logistics of vaccines is a challenging task. The cold chain is indispensable for the Covid-19 vaccine drive to the rural areas. The demand for cold storage increases rapidly due to the rapid Covid-19 vaccine drive. The conventional cold storage facility has a more significant threat to the grid power quality and environmental impacts. The energy demand and greenhouse gas emission of traditional cold storage lead to global warming. The micro cold storage facility has to be developed rapidly to accelerate the vaccine drive to the last mile of the county with reliable and affordable energy sources. In addition, climate change mitigation is ensured by the renewable energy utilization in the Covid-19 vaccine drive. The proposed novel micro cold storage aims to be silent, clean, mobile, without moving parts, and reliable for the last-mile vaccine logistics as a vaccine carrier to the remote rural areas. This paper deals with the novel design, development, and experimental investigation of solar photovoltaic powered thermoelectric-based micro cold storage as a Covid-19 vaccine carrier for rural areas. The design consideration of Covid-19 vaccine storage has been reported. The experimental results ensure the World Health Organization recommended vaccine storage (i.e., vaccine carrier) temperature range of +2 to +8 °C. Therefore, green energy and refrigeration system provide environmental sustainability by mitigating 700kg of annual carbon emission.
اظهر المزيد [+] اقل [-]A novel solar-powered milk cooling refrigeration unit with cold thermal energy storage for rural application
2022
Sidney, Shaji | Prabakaran, Rajendran | Kim, Sung Chul | Dhasan, Mohan Lal
This experimental study analyzed the use of solar photovoltaic energy for operating a novel twin-circuit DC milk chiller without batteries using water-based cold thermal energy storage for different seasons in Chennai, India. HFC-134a and HC-600a were used as refrigerants in the two individual circuits. For each season, the test was conducted continuously for 18 days to analyze the quantity of generated ice that could be utilized to chill 10 L of milk in the morning and in the evening. The average quantity of ice formed per day in the ice bank during monsoon, winter, and summer seasons was found to be 3.61, 19.75, and 27.97 kg, respectively. Thus, it is evident that the use of solar energy with thermal energy storage is effective for operating the milk chilling unit for two seasons, namely winter and summer. However, the system requires an additional power source for continuous operation during the monsoon season. It is noteworthy to mention that the use of a solar milk chiller instead of a conventional milk chiller resulted in 91.15% lesser CO₂ emission with 27.6% less LCC. In this study, solar photovoltaic power was observed to be a good choice for chilling milk in the context of global warming and energy consumption. The use of thermal energy storage also allows the initial cost to be reduced.
اظهر المزيد [+] اقل [-]Diazinon reduction in apple juice using probiotic bacteria during fermentation and storage under refrigeration
2021
Rezaei, Farahnaz | Nejati, Roghayeh | Sayadi, Mehran | Nematollahi, Amene
The main objective of this work was to study the effects of probiotic strains, probiotic primary inoculated population, concentrations of spiked diazinon, physiology of probiotic bacteria, fermentation times, and cold storage period in six consecutive stages on diazinon reduction in apple juice. Chemical properties (pH, total acidity, and sugar content), probiotic viability, and diazinon reduction percent were monitored during fermentation and cold storage. Dispersive solid phase extraction (dSPE) followed by gas chromatography-mass spectrometry was used to extract and measure diazinon concentration. Results showed that Lactobacillus acidophilus revealed the highest ability to reduce diazinon in apple juice after fermentation. Inoculation of L. acidophilus at 9 log CFU/mL showed significantly higher diazinon reducing ability than 7 log CFU/mL. L. acidophilus reduced diazinon in apple juice samples containing 1000 μg/L of spiked diazinon significantly higher than those containing 5000 μg/L. Heat-killed (dead) L. acidophilus bacteria reduced less diazinon content at the end of fermentation than viable bacteria. Furthermore, 72 h of fermentation was more effective in diazinon reduction. Spiked diazinon is completely disappeared at the end of cold storage (28 days) in treatments containing L. acidophilus, while the viability of probiotic bacteria required for causing health-promoting properties was maintained in apple juice.
اظهر المزيد [+] اقل [-]