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This paper deals with various energy converters, in particular thermal or chemical engines and fuel cells. Applying a general thermodynamic framework we derive formulae for converters' efficiencies and apply them to estimate power limits in these power systems. We consider power limits for thermal systems propelled by differences of temperatures and chemical or electrochemical systems driven by differences of chemical potentials. We focus on fuel cells which are the electrochemical energy generators. We show that fuel cells satisfy the same modeling principles as thermal machines and apply similar computational schemes.

In this paper, the effect of the process parameters such as laser power, shielding gas flow and scanning velocity on the actual laser power reaching the surface and thermal efficiency is investigated. For this purpose, the response surface methodology was used to investigate the effect of the process parameters at three levels. In order to measure the data from a 316L stainless steel, four k-type thermocouples are installed in different positions relative to the motion of the laser beam. The actual power was calculated by reverse analysis using the simulated annealing technique and the temperature history was measured by the thermocouples. The thermal model used is an optimized Rosenthal model, which is considered variable with temperature. The results show that for all thermocouples, the highest values of actual power that reached the surface were obtained at laser power of 200W, scanning velocity of 2mm/s and shielding gas flow of 30Lit/min. In addition, by increasing the laser power from 100 to 200W, the thermal efficiency decreases by about 4% to 12%. The thermal efficiency also decreases by about 8%, when the scanning velocity increased from 1 to 3mm/s. Moreover, the increase of the shielding gas flow from 25 to 35Lit/min initially improved the thermal efficiency and then decreased it. The models obtained from the analysis of variance in the heating cycle are in good agreement with the experimental results, but in the cooling cycle, the accuracy of this model decreases.

A Journey Inside the Human Body

Seward Stomacher Enables Clean and Odour Free Sample Preparation for Faecal Transplants.

SCIEX and QPS Holdings Enter Collaboration to Establish the BioBA Solution for Bioanalysis of Biologics.

Singapore Ranks 4th in How Its National Policies Impact Global Biopharma Innovation, ITIF Finds in New Analysis Marking World Health Day.

Bosch Introduces New Generation of Pure Steam Generators and Distillation Units to the Market.

Clearbridge BioMedics Partners with the ICR and The Royal Marsden to Demonstrate Label-free Approach in Isolating Heterogeneous Circulating Tumour Cells (CTCs) and PD-L1 Positive CTCs.

Treatment Brings New Hope for Patients Suffering From Fatal Lung Disease.

(Infographic): About Idiopathic Pulmonary Fibrosis (IPF).

Solar energy is the abundantly available source of renewable energy with least impact on environment. Direct absorption solar collector (DASC) is the commonly used device to absorb heat directly from sun and make use of it for different heating applications. In the past, many experiments have been done to increase the efficiency of DASC using nanofluids. In this paper, an examination of solar collector efficiency for hybrid CeO₂/CuO–water (0.1% by volume) nanofluid under various flow rates and proportions of CeO₂/CuO nanoparticles is investigated. The experiments were conducted at flow rates spanning from 20cc/min to 100cc/min and with CeO₂/CuO nanoparticles proportions of 1:0, 1:0.5, 1:1, 0.5:1 and 0:1. The efficiency increases from 16.5% to 51.6% when the flow rate is increased from 20cc/min to 100cc/min for hybrid CeO₂/CuO (1:1)–water nanofluid. The results also showed an increase in efficiency of 13.8%, 18.1%, 24.3%, 24.9% and 26.1% with hybrid combination of CeO₂/CuO at ratios 1:0, 1:0.5, 1:1, 0.5:1 and 0:1, respectively, in comparison with water at a flow rate of 100cc/min.

With the development of nanotechnology, building a new technology area in a variety of fields and achieving the best performance has become possible. Several studies on the performance of a solar heating system have been conducted using various nanofluids because the efficiency of heat transfer of nanofluids is high. Various previous studies, including theoretical, numerical, and experimental methods, were conducted using nanofluids for flat-plate, evacuated tube, direct solar absorption, parabolic trough, and heat pipe solar collectors. The present work provides an overview of the recent research on the performance of evacuated tube solar collectors using various nanofluids. The experimental and numerical results reported by several researchers, such as the thermal conductivity, heat capacity, and heat transfer coefficient of nanofluids, are first reported. The studies on the evacuated tube solar collectors with nanofluids were then investigated and summarized.

Natural gas consists mainly of methane (CH₄) and ethane (CH₃CH₃) and other hydrocarbons in small quantities. Depending on the source it may also contain CO₂, nitrogen (N₂), hydrogen sulfide (H₂S) and helium (He). It is very abundant and its combustion contributes to the increase of the CO₂ content in the biosphere. Natural gas is a non-renewable fuel (Section 5.1). It is widely used to produce electricity, heat, chemicals including hydrogen, and hydrocarbons (liquid fuels) and as a fuel for motor vehicles…