Effect of water flow rate on quantity and quality of lettuce (Lactuca sativa L.) in nutrient film technique (NFT) under hydroponics conditions

In the study of hydroponics, questions have risen concerning about ideal water flow that allow the plant to absorbing highest amount of nutrient from the nutrient solution during irrigating process. Thus, this experiment was aimed to determine the ideal water flow rate in nutrient film technique system in order to optimize the nutrients uptake with growth of lettuce. Different flow rates 10, 20 and 30 L/hour were assigned as T1, T2 and T3, respectively, with lettuce plants and the space between plants 15 cm. Generally, the growth decreased significantly with increasing in water flow rate. The analysis of lettuce hydroponics variable reveals that flow rate at 20 L/hour provides higher mean rank rather than other flow rate 10 L/hour and 30 L/hour. The findings of this research stated that if flow rate is increased to 30 L/hour plant height, number of leaves, number of outer and inner leaves, heat mass and stem mass decreases. On the whole from the analysis it is concluded that for flow rate 20 L/hour enhances the growth rate of lettuce in hydroponics hence it is stated that flow rate of 20 L/hour is good flow rate rather than 10 L/hour and 30 L/hour. Water flow in nutrient film technique is essential to be ideal through allow the plants root to absorb all elements needed form nutrient solutions in hydroponics system. And thus, water movement in the system and the rate of turnover should be designed to ensure good contact time for roots and water flow in the system

Experimental Study on Impact of Thermal-Assisted Machining on SKD11 Steel Machinability

Machining in a heated environment has been used in pressure machining and metal cutting. Thermal-assisted machining is a new machining method performed on conventional machine tools, CNC machines, in which the workpiece is heated before machining. Different heat sources do the thermal-assisted: electrical energy, laser beam, magnetic induction. However, there is very little research on thermal-assisted machining when milling SKD11 steel, a difficult-in-processing material but widely used in the industry. Material machinability refers to the ability of material machining that is difficult or easy. Material machinability is measured by tool life, material removal ability, shear force, cutting vibration, surface roughness. The material's machinability is directly influenced by its microscopic structure and is related to the cutting mode. This paper has highlighted the study of material machinability when thermal-assisted machining and compared to the conventional one. This study also highlights the crucial role in assessing the effect of heating on the SKD11 steel machinability. This study analyzed the technological parameters' role on the shear force, chip shrinkage, surface roughness, and shear vibrations during normal machining and SKD11 steel heating. The study results showed that the material's microstructure and the amplitude of vibration did not change under the heating process's effect with a temperature range of 200oC - 400oC. However, the shearing force during heat processing is drastically reduced compared to conventional machining. Chip shrinkage increased by 31.7% when heated to 400oC, while roughness decreased by 47.1%

State of the Art in Separation Processes for Alternative Working Fluids in Clean and Efficient Power Generation

Gas turbines must now comply with much stricter emission control regulations. In fact, to combat the greenhouse effect, regulatory authorities have drastically reduced allowable emission levels. For example, in less than 12 years, the United States' Clean Air Act issued the New Source Performance Standards (NSPS), which tightened the NOx emission margin of natural gas combustion (from 75 ppm to 10 ppm). On the other hand, despite those efforts, the high demand for energy produced by fossil-fueled gas turbines in power plants has resulted in dramatic increases in anthropogenic CO2 and NOx emitted by gas combustors. Most systems responsible for these undesirable emissions are directly linked to power generation, with gas turbines playing a pivotal role. Yet, gas turbines are still widely used in power plants and will continue to meet the growing demand. Therefore, sequestration and separation techniques such as Carbon Capture and Storage (CCS) and Air Separation Units (ASU) are essential to reduce CO2 and NOx emissions while allowing large amounts of power to be generated from these systems. This paper provides an in-depth exami-nation of the current state of the art in alternative working fluids utilized in the power generation industry (i.e., gas turbines, combustion). In addition, this paper highlights the recent contribution of integrating separation techniques, such as air separation, steam methane reforming, and water-gas shifting, to the power generation industry to facilitate a continuous and adequate supply of alternative working fluids.Funding: This publication was made possible by NPRP 13 grant # [NPRP13S-0203-200243] from the Qatar National Research Fund (a member of Qatar Foundation). The findings herein reflect the work and are solely the responsibility of the author.Scopu

Isoflavone and protein content in soybeans grains submitted to flooding at different stages of development Teor de isoflavonas e proteínas nos grãos de soja submetida ao alagamento em diferentes estádios de desenvolvimento

The stress imposed on plants by soil flooding constitutes a major barrier to growth and productivity. The identification of soybean varieties that produce higher levels of isoflavones, is necessary as soybeans have been used as human food to reduce risks of chronic diseases. Thus, this study was conducted with the objective of quantifying proteins and isoflavones in soybean cultivars subjected to flooding at various stages of development. The cultivars 'BRS267', 'BRS257' and 'BRS213' were subjected to 15 days of flooding, starting at the stages V6 and V8 and 11 days under stress starting at the stage R4. The proteins in the grain were extracted and quantified and analyzed by SDS-PAGE electrophoresis. Isoflavones were extracted, separated and quantified on HPLC. The electrophoretic analysis of the three cultivars under study revealed the same pattern of banding relative to the total protein regardless of the treatment. However, it was noted that flooding led to an increase in the total contents of isoflavones in the BRS 267 plants flooded in stage R4, remaining constant in other cultivars.<br>O estresse imposto às plantas pelo alagamento do solo constitui uma barreira para o crescimento e produtividade destas. A identificação de cultivares de soja que possam produzir maior teor de isoflavonas torna-se necessária à medida que a soja vem sendo utilizada na alimentação humana e para redução dos riscos de doenças crônicas. Dessa forma, o presente estudo foi realizado com o objetivo de quantificar isoflavonas e proteínas em cultivares de soja submetidas ao alagamento em diferentes estádios de desenvolvimento. As cultivares 'BRS 267', 'BRS 257' e 'BRS 213' foram submetidas a 15 dias de alagamento, nos estádios V6 e V8 e 11 dias sob estresse, no estádio R4. As proteínas no grão foram extraídas e quantificadas e analisadas as eletroforeses em SDS-PAGE. Os isoflavonóides foram extraídos, separados e quantificados por HPLC. A análise por eletroforese das três cultivares revelou o mesmo padrão de bandas relativas às proteínas totais, independente do tratamento utilizado. O alagamento promoveu aumento no teor total de isoflavonas nas plantas alagadas no estádio R4 da cultivar 'BRS 267', permanecendo constante nas demais cultivares