Cycle Analysis Research Articles

Application of Student Team Achievement Division (STAD) in Improving Students Activities and Learning Achievements

This experiment aims to describe the results of the application of the STAD learning model in increasing physics learning activities and achievements. The subjects studied were students of class VII-1 of Kediri State Islamic Junior High School 2. This study uses a qualitative method with the type of CAR (Classroom Action Research). The research subjects in this study were students of class VII-1 even semester 2018/2019 academic year total 31 students. The results of data analysis in cycle 1 showed that student achievement had not reached the passing standard and student activity was still in the low category. While the results of data analysis in cycle 2 showed that student achievement had reached the passing standard and student activities had increased in all aspects except for the aspects of oral activities, drawing activities, and mental activities which had not yet reached the standard passing indicators. Thus, it can be concluded that the application of the STAD model can increase student activity and achievement.

Theoretical Analysis of a self-condensing CO2 Transcritical Power Cycle with regeneration involving DPS in a Solar Thermal Power Plant

Abstract The choice of heat transfer fluids(HTF) significantly dictates the thermal efficiency of the solar power plant. Presently, molten salt is widely used choice owing to its phase, low cost and non-toxic nature. Along with other alternatives like liquid metals, multiphase fluids, these HTFs are limited to peak operating temperatures ranging from 300-550°C. With the introduction of Dense Particle Suspensions (DPS) as an HTF, the highest operating temperatures in a Solar thermal power plant can reach up to 700°C, offering considerable scope for improving thermal efficiency. Due to the higher average specific heat as compared to the alternatives, CO2 is a promising working fluid in the considered range of moderately high operating temperatures. The cost of the components and size of the power block makes the transcritical CO2 cycle an attractive alternative. The present work analyses the theoretical efficiency of the proposed cycle, with the peak operating temperature ranging from 550°C to 700°C. The effects of the variation in the lower operating pressure and the condensation temperature have also been analysed. It is observed that thermodynamic efficiencies as high as 40% can be reached at the maximum operating temperature. The optimum combination of the lower operating pressure and the condensation temperature is also noted.

Controversial Analyzing of a Vapor-Compression Cycle in Various Climatic Conditions Using Various Refrigerants

Abstract This research is about “controversial analysis of a refrigeration vapor-compression cycle,” using R22, and environmentally friendly hydrofluorocarbon (HFC) refrigerants such as R134a, R407c, and R410a in various climatic conditions. For initiation, a complete database was provided for thermophysical properties of the refrigerants’ performances. Then, P–h, s–T, s–h equations are derived in matlab and Excel with the maximum R2. Meanwhile, five climatic conditions (from hot to cold state) are assumed. Consequently, temperature, pressure, enthalpy, and entropy of the cycle states are illustrated for aforesaid conditions as per working fluids properties in the form of quadripartite diagrams. Subsequently, the cycle was analyzed thermodynamically. The coeffcient of performance (COP) was performed for refrigeration (cooling procedure), heat pump (heating procedure), and both heating and cooling for both standard and actual conditions. Afterward, the calculation was performed for parameters like energy efficiency ratio (EER), heat rejected ratio (HRR), capacity, energy, exergy, irreversibility, and exergy destruction ratio (EDR) of each system component according to the first and second laws of thermodynamics, individually. Derived and calculated values in each session illustrated in 3D diagrams on which TEvap s, TCond s and working fluids for each assumed climatic condition can be distinguished easily. A concise analytic study was performed for the increasing and decreasing in values. Forecast for two steps upper and lower than all values derived for trending. Making a trend for indicating either positive or negative inclines of the values and proposing a development for all similar cycles can be considered as the novelty of this research.

MiR-93-5p suppresses ovarian cancer malignancy and negatively regulate CCND2 by binding to its 3\u2032UTR region

Ovarian cancer is the most fatal gynecological cancer worldwide, yet the fundamental mechanism of malignancy acquisition in ovarian cancer remains unknown. miRNA has been implicated to a variety of diseases, including cancer initiation and progression. Cyclin-D2 (CCND2) is ubiquitously implicated in cancer uncontrol cell proliferation. Bioinformatic research revealed that CCND2 is a candidate gene for miR-93-5p with a binding site in its 3′UTR region in the current study. Using our ovarian cancer sample, we verified that miR-93-5p is negatively correlated with CCND2 mRNA and protein levels. Luciferase report assay revealed miR-93-5p inhibits CCND2 production through binding to the 3′UTR region. The expression of miR-93-5p in ovarian cancer patient samples was then determined, and a survival analysis was performed. Our findings showed that miR-93-5p is downregulated in ovarian cancer and is a favorable predictive factor in ovarian cancer patient. CCK8 assay, wound healing assay and flow cytometry-based cell cycle and apoptotic cell analyses were employed here. We found that miR-93-5p suppresses ovarian cancer cell proliferation and migration while enhances cell death. Our research certified that miR-93-5p reduces ovarian cancer malignancy by targeting CCND2.

Circ_FURIN knockdown assuages Testosterone-induced human ovarian granulosa-like tumor cell disorders by sponging miR-423-5p to reduce MTM1 expression in polycystic ovary syndrome

BackgroundPolycystic ovary syndrome (PCOS) is a common endocrine disorder among reproductive-age women. The mechanism by which circular RNA (circRNA) drives PCOS development remains unclear. Thus, the study is designed to explore the role of a novel circRNA, circ_FURIN, in the PCOS cell model and the underlying mechanism.MethodsPCOS cell model was established by treating human ovarian granulosa-like tumor cells (KGN) with Testosterone (TTR). RNA expressions of circ_FURIN, microRNA-423-5p (miR-423-5p) and myotubularin 1 (MTM1) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Protein expression was checked by Western blot. Cell proliferation was investigated by a 5-Ethynyl-29-deoxyuridine assay, 3-(4,5-Dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry analysis for cell cycle. Apoptotic cells were quantified by flow cytometry analysis for cell apoptosis. The interplay between miR-423-5p and circ_FURIN or MTM1 was identified by dual-luciferase reporter and RNA pull-down assays.ResultsCirc_FURIN and MTM1 expressions were significantly upregulated, whereas miR-423-5p was downregulated in the ovarian cortex tissues of PCOS patients and TTR-treated KGN cells compared with controls. Circ_FURIN depletion relieved TTR-induced proliferation inhibition and apoptosis promotion. Besides, knockdown of miR-423-5p, a target miRNA of circ_FURIN, rescued circ_FURIN knockdown-mediated effects under TTR treatment. MiR-423-5p remitted TTR-induced cell disorders by binding to MTM1. Moreover, circ_FURIN modulated MTM1 expression through miR-423-5p.ConclusionCirc_FURIN silencing protected against TTR-induced dysfunction by the miR-423-5p/MTM1 pathway in human ovarian granulosa-like tumor cells.

Multi-objective optimization and off-design performance based on thermodynamic -economic-environmental analysis of organic Rankine & Kalina cycles for roller kiln waste heat recovery

ABSTRACT Heat recovery from roller kiln’s flue gas and cooling gas is interest topic to make ceramic tile production cleaner and more sustainable. Comparatively, the parallel double-evaporator regenerative organic Rankine cycle (PD-RORC) & Kalina cycle (PD-KC34 (Kalina cycle 34)) provide a good solution for a roller kiln’s low-temperature double heat sources utilization. In this research, the off-design performance of the multiobjective optimized PD-RORC & PD-KC34 based on thermodynamic-economic-environmental model is investigated to provide dependable assessment for the roller kiln’s waste heat recovery. Firstly, the multiobjective optimization of PD-RORC & PD-KC34 is carried out considering thermodynamic, economic and environmental factors, and TOPSIS method is used to select the optimal Pareto solution. Then, the influences of the roller kiln’s operating conditions and heat sink on the off-design performances of PD-RORC & PD-KC34 are further explored. The results show that, under the optimal condition, PD-RORC has superior exergy efficiency () and environmental performance with of 49.76% and environment impact load () of 0.096 mPEChina,90/kWh while PD-KC34 has better net power output () and economic behavior with of 250.72 kW and electricity production cost () of 0.090 $/kWh. In addition, excess air coefficient has the greatest impact on , , and for PD-RORC and PD-KC34. On the whole, PD-KC34 has higher sensitivity on and while PD-RORC shows greater sensitivity on and .

Solar Radiation Components on a Horizontal Surface in a Tropical Coastal City of Salvador

Renewable energy must be prioritized by humankind, mainly if there is an expected increase of 50% in energy consumption by 2030 and climate change scenarios are also confirmed. Urban areas consume 70% of the available energy on the planet. Brazil, the largest country in South America, concentrates more than 85% of its population in urban areas, facing a challenge to increase the renewable power plants in its energy matrix. This work presents the solar radiation components behavior for the city of Salvador to contribute with initiatives for the use of solar energy resource. Firstly, a radiometric platform was implemented to obtain direct measurements of global (EG) and diffuse (EDF) components of incoming solar radiation at the surface. The knowledge of EDF is an important requirement to support photovoltaic system projects, and there is no information on direct measurements of this component in the State of Bahia. The diffuse radiation measurement device (DRMD) was designed and built for this purpose. The measurements of solar radiation components performed in this research were submitted to a specific quality control, statistically analyzed and used to evaluate the performance of different empirical models to represent the behavior of EDF in the tropical coastal city. The results demonstrate the potential to explore solar energy in the city of Salvador, with annual values of sunshine higher than 2200 h year−1 and average daily intensities of EG and EDF equal to 18.7 MJm−2day−1 and 7.35 MJm−2day−1, respectively. The analysis of the diurnal cycle shows that EG in summer reaches a maximum of 4.2 MJm−2h−1 and in the rainy season it reaches a minimum of 3.7 MJm−2h−1, both at noon, and in summer the EDFh is 35% of the EGh and it is 46% in the rainy season.

Automatic Identification and Forecasting of Structural Unobserved Components Models with UComp

UComp is a powerful library for building unobserved components models, useful for forecasting and other important operations, such us de-trending, cycle analysis, seasonal adjustment, signal extraction, etc. One of the most outstanding features that makes UComp unique among its class of related software implementations is that models may be built automatically by identification algorithms (three versions are available). These algorithms select the best model among many possible combinations. Another relevant feature is that it is coded in C++, opening the door to link it to different popular and widely used environments, like R, MATLAB, Octave, Python, etc. The implemented models for the components are more general than the usual ones in the field of unobserved components modeling, including different types of trend, cycle, seasonal and irregular components, input variables and outlier detection. The automatic character of the algorithms required the development of many complementary algorithms to control performance and make it applicable to as many different time series as possible. The library is open source and available in different formats in public repositories. The performance of the library is illustrated working on real data in several varied examples.

Study on optimal combination of stratified water injection in extra high water cut period

After several decades of mining, the block has entered the development stage of ultra-high water cut. Although the encryption adjustment and subdivision adjustment for different mining objects have been completed, the interlayer interference is still serious and invalid cycle still exists, making it difficult to develop and adjust. The subdivision adjustment of water injection well can further improve the production degree of various oil layers, effectively improve the utilization rate of water injection, and realize the adjustment of water injection well profile and water injection structure, which is one of the measures with low investment that can effectively improve the development effect of water flooding. To satisfy the needs of the reservoir, fine reservoir, operation based on the production dynamic data and based on the analysis of monitoring data, the application of multidisciplinary reservoir description technology, quantitative analysis of thin layered segment permeability variation coefficient, monolayer onrush of small layer in the paragraph number, interval number, sandstone thickness influence on subdivision adjustment effect, analysis of well test cycle and operation costs influence on economic benefits, A series of combination parameters of subdivision water injection interval are obtained, which can guide the subdivision water injection program, effectively alleviate the range of production decline and water cut rise, and provide technical support for fine tapping potential of water flooding in ultra-high water cut period.

Energy and exergy analyses of a cryogenic reverse Brayton cycle with waste heat recovery

Energy and exergy analyses of a cryogenic reverse Brayton cycle with waste heat recovery

Exergy and exergoeconomic analyses of an ORC-assisted vapor compression refrigeration cycle

Exergy and exergoeconomic analyses of an ORC-assisted vapor compression refrigeration cycle

Exergy analysis of a HDH-VCR cycle for water and air conditioning

Exergy analysis of a HDH-VCR cycle for water and air conditioning

Performance Analysis of Waste Heat Organic Rankine Cycle in Coal-Fired Power Plants

Performance Analysis of Waste Heat Organic Rankine Cycle in Coal-Fired Power Plants

Intelligent Prediction Method of Building Energy Consumption Based on Deep Learning

Building energy consumption prediction plays an important role in realizing building energy conservation control. Limited by some external factors such as temperature, there are some problems in practical applications, such as complex operation and low prediction accuracy. Aiming at the problem of low prediction accuracy caused by poor timing of existing building energy consumption prediction methods, a building energy consumption prediction and analysis method based on the deep learning network is proposed in this paper. Before establishing the energy consumption prediction model, the building energy consumption data source is preprocessed and analyzed. Then, based on the Keras deep learning framework, an improved long short-term memory (ILSTM) prediction model is built to support the accurate analysis of the whole cycle of the prediction network. At the same time, the adaptive moment (Adam) estimation algorithm is used to update and optimize the weight parameters of the model to realize the adaptive and rapid update and matching of network parameters. The simulation experiment is based on the actual dataset collected by a university in Southwest China. The experimental results show that the evaluation indexes MAE and RMSE of the proposed method are 0.015 and 0.109, respectively, which are better than the comparison method. The simulation experiment proves that the proposed method is feasible.

New approaches to the organization of district heating

District heating systems in Ukraine's cities are in deep crisis and need decisive action to overcome it. The crisis began long ago, in the 1990s, and is gradually deepening. Several attempts to stop this process and level the playing field at the state level have failed. At the same time, the process of intensive development of such systems has begun in the countries of Northern Europe. Moreover, both at the theoretical level and in the practical implementation of theoretical developments. According to the theoretical analysis of the life cycle of district heating systems, they are now in the fourth stage of their development in the countries of Northern Europe. This stage has the main features - low temperatures in the network (temperature graph), the combination of district heating systems with district heating systems and their deep integration into the overall energy system of cities, as well as the gradual replacement of fossil fuels with renewable energy sources. District heating systems in the cities of Ukraine are only in the second stage of development. In order to remain competitive against decentralized systems, a sharp transition to the third and at least partially the fourth stage of development of such systems is required. district heating systems are in the active phase of their expansion in European countries and have great prospects for further development, including in Ukraine. District heating systems together with cold supply systems in the process of development are integrated into the energy supply systems of cities and in general in the urban economy. Renewable heat sources will increasingly displace the equipment for combustion of excavated fuel with the prospect of complete abandonment of the latter. In order to preserve the remnants of district heating systems in Ukrainian cities, it is necessary to study and use the experience of the Nordic countries and organize this work at the state level. Unfortunately, neither the governing bodies nor the general public have this understanding. The extraordinary task is to improve the skills of managers and the operational status of city district heating systems and officials of city administrations.

Исследование тепловложения при сварке труб различными методами и способами

The article presents the results of the experimental investigations on studying the effect of heat input on the metal-physical properties of the welded joints of pipes with the diameters of 114–406 mm and the wall thicknesses of 9–21 mm from steels X42–X46 according to API 5L standard with various welding technologies. The analysis is given concerning the thermal welding cycles using technologies of manual arc welding with electrodes with a basic and cellulose type of coating, as well as automatic welding technology under a flux layer. The parameters of thermal welding cycles were measured using 12-channel recorder, which received a signal from chromel-alumel thermocouples stamped near the weld. The data obtained was processed in accordance with the program, which included an assessment of the maximum temperatures and temperature gradients, a study of the kinetics of the accumulation of thermal effects in the near-seam zone, and the zone of thermal influence, as well as an assessment of the residence time of the welded joint metal at a temperature above 600 °C. The analysis of thermal cycles using various welding techniques and methods showed that the parameters of thermal welding cycles largely determine the metal-physical properties of the weld metal and the zones of thermal influence, the possibility of trouble-free and long-lasting operation of the structure at various ambient temperatures. It is shown that the choice of the optimal thermal welding cycle allows to obtain high mechanical properties of metal in all the areas of the welded joint, and, also, ensures the production of weld metal with high metallurgical quality, which increases the working condition of the pipeline and the safety of maintenance personnel during its operation. The presented results of the study can serve as a basis for the development of additional requirements for welding technology of steels of various strengths considering the maintenance of the working condition of the structure as a whole.

C1QTNF6 promotes oral squamous cell carcinoma by enhancing proliferation and inhibiting apoptosis

BackgroundC1QTNF6 (CTRP6), a member of the CTRP family, has recently been implied to play a role in the tumorigenesis of for a variety of cancer types. However, the role of C1QTNF6 in oral squamous cell carcinoma (OSCC) and its potential molecular remains unclear.MethodsC1QTNF6 expression was detected by qRT-PCR and western blot analysis. Lentiviral vectors were constructed to knockdown C1QTNF6 in CaL27 and SCC-9 human OSCC cell lines. Cell viability, cell cycle and cell apoptosis analyses were performed by MTT assay, PI/Annexin V staining, and flow cytometry. The effect of C1QTNF6 knockdown on in vivo tumorigenicity of OSCC cells in vivo was evaluated using nude mouse xenograft tumor model. Downstream signaling mechanisms were identified by microarray and Ingenuity Pathway Analysis.ResultsImmunohistochemistry of OSCC tissue and data from TCGA demonstrate that C1QTNF6 was overexpressed in OSCC tissues, and that cellular proliferation was significantly decreased after C1QTNF6 was knockdown in CaL27 and SCC-9 cell lines. Knockdown of C1QTNF6 also resulted in cell cycle arrest at the G2/M phase and enhanced cell apoptosis in in CaL27 and SCC-9 cell lines. Furthermore, knockdown of C1QTNF6 in Cal-27 cells inhibited tumor growth of OSCC in vivo. Microarray analysis revealed that C1QTNF6 silencing resulted in significant alterations of gene expression, with the Acute Phase Response signaling pathway significantly activated following C1QTNF6 silencing.ConclusionsThese results suggest that C1QTNF6 plays an important role in promoting OSCC tumorigenesis, which indicates that C1QTNF6 may comprise a promising therapeutic target for OSCC treatment.

The Passion Cycle in the Sanctuaries of the Saxon Fortified Churches in Southern Transylvania

"This paper aims to reconstitute the pictorial program of some medieval Saxon churches’ sanctuaries, which are Mălâncrav, Curciu, Râşnov and Sibiu, with particular interest on the images regarding the Passion Cycle. The article will try to bring a stylistic and iconographic analysis of the Passion Cycle in the sanctuary, episodes that usually appear on the northern choir wall. Therefore, we aim to highlight the reasons why this Passion narrative was chosen to decorate this part of the sanctuary and what was its role both regarding the place that it occupies, that is near the most sacred place of the church, and also the role it had in the religious services. Given the complexity of the narrative programs and the strong link with the biblical texts, the paintings have a double role, both educational and devotional. Keywords: Passion Cycles, mural painting, fortified churches, iconography "

Chromatin accessibility analysis identifies GSTM1 as a prognostic marker in human glioblastoma patients

BackgroundGlioblastoma (GBM) is a malignant human brain tumor that has an extremely poor prognosis. Classic mutations such as IDH (isocitrate dehydrogenase) mutations, EGFR (epidermal growth factor receptor) alternations, and MGMT (O6-methylguanine-methyltransferase) promoter hypermethylation have been used to stratify patients and provide prognostic significance. Epigenetic perturbations have been demonstrated in glioblastoma tumorigenesis. Despite the genetic markers used in the management of glioblastoma patients, new biomarkers that could predict patient survival independent of known biomarkers remain to be identified.MethodsATAC-seq (assay for transposase accessible chromatin followed by sequencing) and RNA-seq have been used to profile chromatin accessible regions using glioblastoma patient samples with short-survival versus long-survival. Cell viability, cell cycle, and Western blot analysis were used to characterize the cellular phenotypes and identify signaling pathways.ResultsAnalysis of chromatin accessibility by ATAC-seq coupled with RNA-seq methods identified the GSTM1 (glutathione S-transferase mu-1) gene, which featured higher chromatin accessibility in GBM tumors with short survival. GSTM1 was confirmed to be a significant prognostic marker to predict survival using a different GBM patient cohort. Knockdown of GSTM1 decreased cell viability, caused cell cycle arrest, and decreased the phosphorylation levels of the NF-kB (nuclear factor kappa B) p65 subunit and STAT3 (signal transducer and activator of transcription 3) (pSer727).ConclusionsThis report demonstrates the use of ATAC-seq coupled with RNA-seq to identify GSTM1 as a prognostic marker of GBM patient survival. Activation of phosphorylation levels of NF-kB p65 and STAT3 (pSer727) by GSTM1 is shown. Analysis of chromatin accessibility in patient samples could generate an independent biomarker that can be used to predict patient survival.

Network analysis of nanoscale energy conversion processes

Energy conversion in nanosized devices is studied in the framework of state-space models. We use a network representation of the underlying master equation to describe the dynamics by a graph. Particular segments of this network represent input and output processes that provide a way to introduce a coupling to several heat reservoirs and particle reservoirs. In addition, the network representation scheme allows one to decompose the stationary dynamics as cycles. The cycle analysis is a convenient tool for analyse models of machine operations, which are characterized by different nanoscale energy conversion processes. By introducing the cycle affinity, we are able to calculate the zero-current limit. The zero-current limit can be mapped to the zero-affinity limit in a network representation scheme. For example, for systems with competing external driving forces the open-circuit voltage can be determined by setting the cycle affinity zero. This framework is used to derive open-circuit voltage with respect to microscopic material energetics and different coupling to particle and temperature reservoirs.