NOPR Community:

Estimation of state of charge of lead-acid battery used in solar photovoltaic system

2020-01-29T06:01:12Z

Title: Estimation of state of charge of lead-acid battery used in solar photovoltaic system Authors: Kumar, Sonu; Sethuraman, C Abstract: An accurate estimation of State of charge (SOC) of the lead-acid battery is of paramount importance for the efficient and reliable operation of solar photovoltaic (SPV) sytem. There are mainly four methods used for estimating SOC of the battery, viz. chemical, voltage, current integration and kalman filtering. In this present study, the SOC as indicated by the solar power conditioning unit (SPCU) was taken as reference and at every 5% SOC reduction, the other parameters such as- i) specific gravity of electrolyte, ii) battery terminal voltage, iii) (Ampere Hour) Ah and iv) energy deliverd to the resistive load were recorded. Based on this recorded values the SOC was predicted. The standard deviation (S.D.) of the difference of predicted SOC to the reference SOC was calculated based on specific gravity, Voltage, Ah and energy. The SD obtained was 6.17, 5.67, 0.33, 0.75 respectively. The specific gravity value for the battery electrolyte decreases with the decrease in the battery SOC%, the maximum value of SG at 100% SOC was 1.23 and the minimum at 20% SOC was 1.14. The terminal voltage was also got reduced with the reduction in SOC, from 24.85V at 100% SOC to 22.4V at 20% SOC. The energy stored by the battery during charging was 3.65 units and the energy delivered from the battery to the load was 3.245 units. The efficiency of solar panel, lead-acid battery and the combined SPV system was 12.79%, 88.9% and 9.68% respectively. It was found that the SOC of the lead-acid battery would be more accurate when it is estimated based on current integration i.e., Ah, the SOC estimation based on energy is also acceptable since the SD for both is less than 1. Hence, through this investigation we can say that SOC prediction based on Ah or kWh measurement is more appropriate than specific gravity and voltage methods. Page(s): 7-19

An eco-friendly approach towards leather dyeing using fungal pigments

2020-01-29T05:58:48Z

Title: An eco-friendly approach towards leather dyeing using fungal pigments Authors: Sivaranjani, V; Khambhaty, Yasmin; Saravanan, P Abstract: There is a growing demand for eco-friendly and non-toxic dyes that can be used to impart colour to a wide variety of materials. Many synthetic dyes are known to cause health hazards due to possible carcinogenic effects associated with high heavy metal concentration and the possible use of other restricted substances. The present study aims at the extraction of pigments from fungi, which can be used as an alternative to synthetic dyes used for leather dyeing. The use of agricultural wastes for enhanced fungal growth and pigment production was also envisaged. The pigment thus obtained was subjected to characterization using analytical techniques like CHNS, FTIR, DSC and TGA. These pigments were further used for leather dyeing and effect of process parameters like colour fastness, rub fastness and heat resistant properties were analyzed and conditions optimized. Page(s): 20-25

Studies on sodium aerosol characteristics for safety studies of sodium cooled fast reactor

2020-01-29T05:57:27Z

Title: Studies on sodium aerosol characteristics for safety studies of sodium cooled fast reactor Authors: Kumar, Amit; Sujatha, P N; Usha, P; Subramanian, V; Srinivas, C V; Baskaran, R; Venkatraman, B Abstract: The liquid sodium is used as coolant in Sodium cooled Fast Reactors (SFR's). When liquid sodium reacts with air it produced sodium combustion aerosols. These aerosol are very hazardous to the human and corrosive for instruments. In this context, the studies on the physical and chemical characteristics of sodium aerosol are very important for safety of SFR. In this article, the sodium aerosol characteristics and properties produced under normal operation as well as reactor accident are presented. The sodium aerosol in the cover gas region is produced by evaporation and condensation of sodium while in SGB and RCB sodium aerosol are produced by sodium combustion process. The size distribution (Mass Median Diameter-MMD) and concentration of sodium aerosol in cover gas varies from 1.0 to 12 µm and 0.02 to 31.5 g/m³ when temperature of the sodium pool increased from 250-550°C on other hand the MMD of sodium combustion aerosol is varies from 1.0 to 4.0 µm when relative humidity increased from 20 to 95%. The concentration of sodium combustion aerosol in RCB and SGB is 3-4 g/m³. The chemical nature of sodium aerosol in cover gas is pure sodioum (Na) while in SGB and RCB are compounds of sodium (NaOH, Na₂CO₃ and NaHCO₃). Page(s): 26-33

Nanotechnology and nanomaterial toxicity

2020-01-29T05:51:02Z

Title: Nanotechnology and nanomaterial toxicity Authors: Pandey, Alok Kumar; Dubey, Kavita; Tewari, Chandra Mohan Abstract: Nanotechnology, a field of research and innovation concerned with building 'things' - generally, materials and devices - on the scale of atoms and molecules. Nanotechnology is hailed as having the potential to increase the efficiency of energy consumption, help clean the environment, and solve major health problems. It is said to be able to massively increase manufacturing production at significantly reduced cost. The new and unique applications offered by nanotechnology in diverse areas have made it so popular that it is being applied today in almost all aspects of daily life. Although the small size and subsequent larger surface area of nanoparticles endow them with some highly useful and specific properties, it also renders them more active leading to unexpected and unanticipated consequences on interaction with biological systems. The biokinetics of nanoparticles are different from larger particles. When inhaled, they are efficiently deposited in all regions of the respiratory tract; they evade specific defence mechanisms; and they can translocate out of the respiratory tract via different pathways and mechanisms (endocytosis and transcytosis). Some of these nanoparticles not only possess inflammatory and pro-oxidant potential for biological systems, but also have antioxidant activity, which can explain early findings showing mixed results in terms of toxicity of nanoparticles to environmentally relevant species. Manufactured nanomaterials are likely to enter the environment for several reasons. Some are and others will be produced in tons, and any material produced in such mass quantities is likely to reach the environment from manufacturing effluent or from spillage during shipping and handling. They are being used in personal-care products such as cosmetics and sunscreens and can therefore enter the environment on a continual basis from washing off of consumer products. They are being used in electronics, tires, fuel cells, and many other products and it is still unknown whether some of these materials may leak out or be worn off over the period of use. They are also being used in disposable materials such as filters and electronics and may therefore reach the environment through landfills and other methods of disposal. The fate of nanomaterials in aqueous environment is controlled by many biotic/abiotic processes such as solubility, interactions between the nanomaterials and natural/anthropogenic chemicals in the ecosystem. Although humans have been exposed to airborne nanosized particles throughout their evolutionary stages but such exposure has increased dramatically over the last century due to anthropogenic sources. The rapidly developing field of nanotechnology is likely to become yet another source of toxicity through inhalation, ingestion, skin uptake, and injection of engineered nano-materials. Information about ecological risk, safety and potential hazards is urgently needed. Additional considerations for assessing safety of engineered nanoparticles include careful selections of appropriate and relevant doses/concentrations, the likelihood of increased effects in a compromised organism, and also the benefits of possible desirable effects. Before unknowingly dumping a huge amount of dangerous nanomaterials into the environment, we need to investigate the solubility and degradability of engineered NPs in soils and waters, to establish baseline information on their safety. Page(s): 34-42