•Mathematical model of cooling tower based on analogy to distillation column.•Aspen Plus model was developed for cooling tower.•Both models were validated with real plant operating data.•Controller ...was designed to control performance of cooling tower with climate.•Resulted in 30% reduction in overall power consumption of cooling tower.
Cooling towers are unit operations that are used in almost every industry to cool down process water either by natural draft or forced draft. The energy intensive components of cooling towers are draft fans and circulating pumps which in traditional practise run at full rated capacities throughout the year ignoring the underlying opportunities for energy savings. The efficiency of a cooling tower is a function of ambient air temperature, relative humidity and wet bulb temperature. This work brings out a novel model of cooling tower along with an energy harnessing control system based on prevailing climatic conditions thus improving the overall efficiency of the system. Based on analogy to a distillation column with hypothetical stages a model for cooling tower is developed. Then a model predictive control is designed to control the draft fan speed and pump flow rate of cooling tower based on climatic conditions. Both the model and control strategy was developed using Aspen Plus (V12.1), MATLAB (R2018b) and Simulink softwares and has been validated and trained based on plant operating data. The developed model was then tested at a pilot cooling tower facility of capacity 1 Ton of Refrigeration and was observed to attain approximately 30% reduction in energy consumption compared to the traditional operation.
There is increasing evidence of adverse health impact of solid biomass fuel, and its use may hinder thermal comfort, which may lead to lower quality of life. Hence, current study aims to assess the ...thermal comfort at a rural location of Punjab, India. The indoor air temperature and relative humidity in rural households during winter varied from 11.9–25.2 °C and 63.4–90.5% respectively, during pre-summer it ranged between 21.3 and 27.4 °C and 48.4–78.4% while during summer it ranged between 28.4 and 37.8 °C and 13.7–63.8% respectively. The PMV of the households ranged between −0.85 to 0.69 (winter), −0.32 to 0.4 (pre-summer) and 0.53 to 1.25 (summer) for American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 55-2017 and −0.56 to 1.11 (winter), 0.04 to 0.99 (pre-summer) and 1.21–2.36 (summer) for European Committee for Standardization (CEN) European standard EN15251 while the Predicted Percentage of Dissatisfied ranged between 5 and 20% (winter), 5–8% (pre-summer) and 11–38% (summer) for ASHRAE 55-2017 and 5–31% (winter), 5–26% (pre-summer) and 36–90% (summer) for EN15251 guidelines. On the other hand, Adaptive thermal comfort (ATC) during winter and pre-summer was comfortable for 80 and 90% acceptable limits (ASHRAE-2017) and ranged between too cool to comfortable for EN15251 (Class I, II and III) while during summer thermal comfort for occupants was comfortable for ASHRAE 2017 and EN15251 (Class I, II, III) but did not comply with EN guidelines in some households using either clean fuel or chullah. Thermal comfort sensation was observed to be slightly cool to neutral during winter, neutral during pre-summer and slightly warm during summer according to Predicted Mean Vote method. The results were also compared using a thermal comfort and household survey and found to be similar with the model results. Climate change is leading to changes in temperature which may have an impact on the built environment. Hence, the current study suggests formulating policies on the uses of household fuel and design of kitchen with proper ventilation to increase thermal comfort which in turn will also reduce air pollutants.
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•First study reporting the thermal comfort in rural households of India.•PMV of rural households ranged between -0.32 to 1.25 as per ASHRAE 55-2017 standards•Thermal comfort was observed slightly warm during summer months.•SBF not only causes household air pollution but also affects the thermal comfort.•Need to formulate policies to ensure adequate thermal comfort in households' microenvironments
Enhancement of transcription by a splicing-competent intron is an evolutionarily conserved feature among eukaryotes. The molecular mechanism underlying the phenomenon, however, is not entirely clear. ...Here we show that the intron is an important regulator of promoter directionality. Employing strand-specific transcription run-on (TRO) analysis, we show that the transcription of mRNA is favored over the upstream anti-sense transcripts (uaRNA) initiating from the promoter in the presence of an intron. Mutation of either the 5' or 3' splice site resulted in the reversal of promoter directionality, thereby suggesting that it is not merely the 5' splice site but the entire splicing-competent intron that regulates transcription directionality. ChIP analysis revealed the recruitment of termination factors near the promoter region in the presence of an intron. Removal of intron or the mutation of splice sites adversely affected the promoter localization of termination factors. We have earlier demonstrated that the intron-mediated enhancement of transcription is dependent on gene looping. Here we show that gene looping is crucial for the recruitment of termination factors in the promoter-proximal region of an intron-containing gene. In a looping-defective mutant, despite normal splicing, the promoter occupancy of factors required for poly(A)-dependent termination of transcription was compromised. This was accompanied by a concomitant loss of transcription directionality. On the basis of these results, we propose that the intron-dependent gene looping places the terminator-bound factors in the vicinity of the promoter region for termination of the promoter-initiated upstream antisense transcription, thereby conferring promoter directionality.
5% Ru-doped MgO and PANI/MgO–Ru nanocomposite were successfully synthesized using sol–gel and in situ polymerization methods, respectively. Several characterization techniques were employed to ...analyze the structural, spectroscopic, topographical, elemental, and chemical properties of the synthesized materials using different characterization techniques. With the help of XRD patterns, the estimated crystallite sizes for 5% Ru-doped MgO nanoparticles and PANI/MgO–Ru nanocomposite were calculated to be 20 and 11 nm, respectively. By examining the SEM results, it was observed that all the materials possess a nearly spherical surface morphology. The availability of pores was also found at the surface of the materials which evinces that the synthesized materials can perform well in the context of gas sensing. The synthesized materials were also examined for LPG sensing investigations. Some noteworthy parameters of LPG sensing such as response time, recovery time, reproducibility, and sensitivity were estimated for all the materials. LPG sensing investigations reveal that the PANI/MgO–Ru might be a promising and excellent sensing material for the fabrication of an efficient LPG sensor.
The dehydration of isopropanol (IPA) is a crucial process in numerous industries, and the optimization of its efficiency and economic viability is essential. This review provides a comprehensive ...analysis and comparison of various distillation processes, heat integration (HI) strategies, and process intensification (PI) techniques employed for IPA dehydration. The advantages, limitations, and applicability of distillation processes, such as extractive distillation, heterogeneous azeotropic distillation, and pressure swing distillation, are discussed. In addition, this review explores the potential of HI techniques to optimize energy consumption and reduce operating costs of IPA dehydration processes. PI techniques, including thermally coupled arrangements and dividing wall columns, are examined for their ability to improve the process efficiency and sustainability. It is crucial to conduct thorough evaluations, as well as energy and economic analyses, when choosing the appropriate distillation process, HI approach, and PI technique for specific IPA dehydration applications. This review emphasizes the potential for improving the energy efficiency, product purity, and cost-effectiveness of IPA dehydration through the integration of advanced distillation processes and PI techniques.
In this paper, the problem of global asymptotic stability of two-dimensional fixed-point state-space digital filters described by the Fornasini–Marchesini second local state-space model with ...saturation nonlinearities has been investigated. By making use of a precise upper bound of the system state vector and a novel passivity property associated with the saturation nonlinearities, a new sufficient global asymptotic stability criterion has been proposed. Presented criterion has been compared with several existing criteria. An illustrative example is given to demonstrate the efficacy of the proposed method.
•New saturation overflow stability criterion for 2-D digital filters is proposed.•Criterion is based on a novel characterization of saturation nonlinearities.•Criterion is less stringent than several existing criteria.
Abstract
We investigated time course of photoperiodically driven transcriptional responses in physiologically contrasting seasonal life-history states in migratory blackheaded buntings. Birds ...exhibiting unstimulated winter phenotype (photosensitive state; responsive to photostimulation) under 6-h short days, and regressed summer phenotype (photorefractory state; unresponsiveness to photostimulation) under 16-h long days, were released into an extended light period up to 22 h of the day. Increased
tshβ
and
dio2
, and decreased
dio3
mRNA levels in hypothalamus, and low
prdx4
and high
il1β
mRNA levels in blood confirmed photoperiodic induction by hour 18 in photosensitive birds. Further, at hours 10, 14, 18 and 22 of light exposure, the comparison of hypothalamus RNA-Seq results revealed transcriptional differences within and between states. Particularly, we found reduced expression at hour 14 of
transthyretin
and
proopiomelanocortin receptor
, and increased expression at hour 18 of
apolipoprotein A1
and carbon metabolism related genes in the photosensitive state. Similarly, valine, leucine and isoleucine degradation pathway genes and
superoxide dismutase 1
were upregulated, and
cocaine- and amphetamine-regulated transcript
and
gastrin-releasing peptide
were downregulated in the photosensitive state. These results show life-history-dependent activation of hypothalamic molecular pathways involved in initiation and maintenance of key biological processes as early as on the first long day.
Buccal cavernous hemangiomas are uncommon vascular lesions, particularly in adult patients. We present a case of a 23-year-old male with a progressive left cheek swelling over three years. Clinical ...examination and radiographic imaging revealed a solid, multilobulated mass in the left buccal and masticator spaces. Surgical excision was performed, and histopathological analysis confirmed the diagnosis of a cavernous hemangioma. This case underscores the importance of recognizing and appropriately managing rare vascular lesions in adult patients.
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