Abstract
Nowadays, different methods are used in the renewable energy sector for the fabrication of prime movers. A broad classification of the latest additive manufacturing technologies is discussed ...with ten different parameters like material used, speed, part size, accuracy, application, surface finish, complexity, costing, strength and weakness. Additive manufacturing or 3D printing is also referred to as digital manufacturing technology. 3D printing technology creates physical objects from a geometrical representation by successive addition of materials. Polylactic acid material will be cost-effective to develop the laboratory scale prototype Pelton turbine model. The fused deposition method gives durable products with plastic filament material. FDM provides an optimum condition for the manufacturing of curved surfaces. A step by step process is emphasis for the digital printing of 3D Pelton buckets, runner and shaft. Difficulties associated with the orientation of the Pelton bucket is overcome by using mechanical support structures.
Hydro-power energy is the most efficient renewable energy sources in the world. India stands in the top ten hydropower generation countries list. Pelton turbine is a well-known hydropower extraction ...machine. The Pelton turbine buckets play an important role in the efficiency of the hydro turbine which is in continuous interaction with high velocity jet and there are possibilities of damages to the bucket in the form of erosion as water contains small debris as sediments. Eroded buckets greatly reduce the efficiency of the turbine. Attempt is made by researchers to developed co-relations to evaluate wear rate and efficiency reduction based on the practical data. The majority of erosion takes place at splitter areas. An erosion cannot be eliminated, but it can be reduced by some amount. The results of the mathematical model indicate that the effect of silt size to the wear rate is 0.0001 gram per gram of bucket weight for a particular silt concentration and the result of silt concentration to wear rate is 0.0007 gram per gram of bucket weight for a particular silt size. The normalised efficiency loss is increased to 0.13% for a specific silt size with the variation of silt contraction. The average wear rate is nearly 3.1 mm per year for laboratory-scale Pelton turbine bucket; which is manufactured from brass and bronze materials. The coating of various materials over the buckets are used by researchers to reduce erosion. Among all coating materials, WC-Co-Cr gives better results against erosion.
The diesel engine is a well-known source to supply energy for vehicles such as marine transportation, industrial sectors, road vehicles. However, the large quantity of diesel engine usages in current ...scenario tends to environmental hazards and that affects the living organisms in a universe. Nowadays, numerous researches have been performed for diminishing the emission of hazardous gases from a diesel engine. For that, the desired amount of water is blended with the engine oil to minimize the particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx) emission, and so on. Moreover, thermal effectiveness of the diesel engine was enhanced with the help of emulsion fuel technique. Henceforth, the current investigation presents a review of water emulsified diesel (WED) fuel performance in the traditional diesel engine. Moreover, this paper is mainly focused on the assessment of emission analysis, combustion of fuel, and physical properties of water–diesel emulsion for the diesel engine. The usage of emulsified fuel has enhanced diesel engine operation. Furthermore, the optimal blend ratio improves the fuel-efficient and reduces fuel emission. The entire research papers of all parameters are compared to validate the effectiveness and improvement of engine performance.
A major cause for the production of higher harmonic forces on the rotating system is the Misalignment between the shafts. This in-turn produces vibrations during the function of any turbine unit that ...can bring about untimely wear of bearings, loosening of disparate fasteners, and crash of the entire installation. Good efficiency can well be ensured by means of the proper alignment with the rotating elements’ motor axis. And it also makes sure that the motion and power transmission happens devoid of significant loss. The misalignment can well be found if there is a variation on the torque at the motor end. Along with it, the misalignment can well be detected by the torque variation. Here, utilizing the theoretical relationship betwixt the deflection factor and harmonic bending force generated on a formed test rig, the torque and power surge are simulated. Aimed at the data analysis, a statistical design centered upon the Responses Surface Methodology (RSM) is employed. The outcomes are plotted utilizing the Box-Behnken (BB) model to perform a simplified economical study that exhibits when a preventive in addition to predictive methodology can well be applied in the instance of misalignment.
ABSTRACT
Blazar S5 0716+714 is well-known for its short-term variability, down to intraday time-scales. We here present the 2-min cadence optical light curve obtained by the TESS space telescope in ...2019 December–2020 January and analyse the object fast variability with unprecedented sampling. Supporting observations by the Whole Earth Blazar Telescope Collaboration in B, V, R, and I bands allow us to investigate the spectral variability during the TESS pointing. The spectral analysis is further extended in frequency to the UV and X-ray bands with data from the Neil Gehrels Swift Observatory. We develop a new method to unveil the shortest optical variability time-scales. This is based on progressive de-trending of the TESS light curve by means of cubic spline interpolations through the binned fluxes, with decreasing time bins. The de-trended light curves are then analysed with classical tools for time-series analysis (periodogram, autocorrelation, and structure functions). The results show that below 3 d there are significant characteristic variability time-scales of about 1.7, 0.5, and 0.2 d. Variability on time-scales $\lesssim 0.2$ d is strongly chromatic and must be ascribed to intrinsic energetic processes involving emitting regions, likely jet substructures, with dimension less than about 10−3 pc. In contrast, flux changes on time-scales $\gtrsim 0.5$ d are quasi-achromatic and are probably due to Doppler factor changes of geometric origin.
Abstract
Impulse turbine is one of the oldest methods of water power extraction. Pelton turbine is one amongst them. There is notable increase in utilization of renewable energy sources and ...hydropower in developed countries. The potential energy of water in hilly areas can fulfill the demands of the rural areas and can also contribute to grids. The power output of a turbine can be increased from the same input by improvising its efficiency. This paper aims to design the Pelton turbine wheel to improve its hydraulic efficiency. Parametric optimization of a Pelton turbine wheel is achieved by two methods: direct search method and efficiency optimization method. The effect of bucket exit angle, specific speed, speed ratio and nozzle opening on hydraulic efficiency is described here. The hydraulic efficiency of the turbine will be higher at the complete nozzle opening and at a higher specific speed. The maximum hydraulic efficiency is achieved for the specific speed 20.77. The theoretical hydraulic efficiency 93.9 percentage is achieved for 15 degrees of exit angle at 0.49-speed ratio.
The current study investigated transcriptional distortion in prostate cancer cells using the vitamin D receptor (VDR) as a tool to examine how epigenetic events driven by corepressor binding and CpG ...methylation lead to aberrant gene expression. These relationships were investigated in the non-malignant RWPE-1 cells that were 1α,25(OH)(2)D(3) responsive (RWPE-1) and malignant cell lines that were 1α,25(OH)(2)D(3) partially responsive (RWPE-2) and resistant (PC-3). These studies revealed that selective attenuation and repression of VDR transcriptional responses in the cancer cell lines reflected their loss of antiproliferative sensitivity. This was evident in VDR target genes including VDR, CDKN1A (encodes p21( (waf1/cip1) )) and GADD45A; NCOR1 knockdown alleviated this malignant transrepression. ChIP assays in RWPE-1 and PC-3 cells revealed that transrepression of CDKN1A was associated with increased NCOR1 enrichment in response to 1α,25(OH)(2)D(3) treatment. These findings supported the concept that retained and increased NCOR1 binding, associated with loss of H3K9ac and increased H3K9me2, may act as a beacon for the initiation and recruitment of DNA methylation. Overexpressed histone methyltransferases (KMTs) were detectable in a wide panel of prostate cancer cell lines compared with RWPE-1 and suggested that generation of H3K9me2 states would be favored. Cotreatment of cells with the KMT inhibitor, chaetocin, increased 1α,25(OH)(2)D(3)-mediated induction of CDKN1A expression supporting a role for this event to disrupt CDKN1A regulation. Parallel surveys in PC-3 cells of CpG methylation around the VDR binding regions on CDKN1A revealed altered basal and VDR-regulated DNA methylation patterns that overlapped with VDR-induced recruitment of NCOR1 and gene transrepression. Taken together, these findings suggest that sustained corepressor interactions with nuclear-resident transcription factors may inappropriately transform transient-repressive histone states into more stable and repressive DNA methylation events.
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