Effects of Receiver Parameters on Solar Flux Distribution for Triangle Cavity Receiver in the Fixed Linear-Focus Fresnel Lens Solar Concentrator

The objective of the study is to investigate and optimize the solar flux uniformity of a fixed linear-focus Fresnel lens solar concentrator using a triangle cavity receiver. The effects of receiver parameters including the vertical distance from the cavity opening plane to the Fresnel lens f, receiver internal surface absorptivity αab, end reflection plane reflectivity ρr, solar declination angle δ and solar angle ω on the uniformity factor (UF) of a triangle cavity receiver were carried out. The effects of receiver parameters are evaluated with a significance test of critical factors. The results showed that the increase in f and δ would result in an increase in the UF. The average UF with f = 600, 625, 650, 675 and 700 mm, respectively, are 0.5030, 0.5858, 0.6337, 0.6576 and 0.6784 for ω in range of 0–60°. Moreover, the UF increases as αab decreases when other receiver parameters are constant for the δ of 0–8°. The ρr has a limited effect on the UF until δ becomes relatively larger and ω becomes relatively smaller. Furthermore, ω effects are most significant on the UF, followed by δ, f and αab. Setting a suitable f is the most economical and effective way to improve the UF.

Determination of Potassium Levels in Bananas Using an Optical Sensor with a Flat and Concave Mirror Plane

Potassium is a nutrient that plays a role in maintaining the function of the muscles and nerves that control the heart and is needed for body stability. The potassium content in the body can be obtained from foods such as bananas. The development of instruments and methods that are developed to obtain a more accurate measurement of potassium concentration requires an instrument that has high linearity and sensitivity. The instrument is in the form of an optical sensor system equipped with the use of optical fibers to guide the waveform to maintain its intensity stability. In this study, an experimental method was conducted with a sample of a standard solution with potassium as the solute and pure water as the solvent. Then continue to measurements on samples of banana milk and green banana fruit extracts. The results of the analysis of the measurement data using an optical sensor with a concave mirror reflection plane obtained a sensitivity of 0.36 mV/ppm and a linearity of 82.56%. In the plane of the flat mirror reflection, obtained an optical sensor with a plane mirror reflection plane shows a sensitivity of 0.12 mV/ppm and a linearity of 97.6%. The highest and most accurate linearity value is found in the plane mirror plane results. The next stage is the result of the maximum output voltage read on the optical detector through an optical sensor with a sample of extracts of milk banana and green banana. The results of data analysis on the linear equation with the highest linearity obtained the potassium content in milk bananas of 391.54 ppm and the green banana extract solution obtained 307.91 ppm, so it can be concluded that the potassium content in milk bananas is higher than green bananas with a linearity of more than 97%.

Change in matrix saturation with alloying elements at primary thermocyclic processing of 44NKhTYu alloy

The total solubility of alloying elements (chromium, titanium, aluminum) in the iron-nickel matrix (Fe – Ni) of 44NKhTYu alloy, depending on the number of cycles, does not occur during primary thermocycling processing (TCP). This is evidenced by the main replicas of the matrix with (111) reflection plane indexes of the samples X-ray images under the studied modes of thermocyclic processing. The maximum solubility of alloying elements is achieved only at total quenching. Special attention should be paid to the third and fourth cycles in the further study of TCP changing the cooling rate in these cycles due to the cooling medium, since with an increase in the number of cycles in the primary TCP, significant changes do not occur.

Низкоэнергетическое состояние электронного пучка в коаксиальном диоде с однородным анодом и неоднородным профилем магнитного поля

The possible formation of an extended low-energy state of electron beam in a coaxial diode with homogeneous cylindrical anode and moderate magnetic field with inhomogeneous profile is demonstrated for the first time. It is established that, depending on the magnetic field configuration, virtual cathodes (VCs) of two types can be formed: (i) a stationary VC with a localized reflection plane and (ii) a moving VC with a two-stream low-energy state of the electron beam.

A wearable microwave absorption cloth

A wearable microwave absorption cloth was assembled from a novel multi-scale graphene-supported carbon/nonwoven composite absorber coupled with a reflection plane. The as-fabricated cloth that fulfills the representative wearable characteristics presents qualified microwave absorption performance, promising outstanding platform for the development of advanced wearable materials in numerous industries.

Reflection Plane Precision Measuring Methods Research of Shipborne Measurement and Control Antenna

In this paper, measuring principle of shipborne measurement and control antenna was introduced, error index analysis was carried out. Main reflection plane replacement of a certain shipborne measurement and control antenna was taken as an example, installation methods of the antenna and measuring methods of main reflection plane precision were described, and solutions to the difficulties in measuring were put forward. Plane precision measuring and data processing were carried out finally. The results showed that, the operability of these methods were high, and the measuring results of reflection plane precision met the necessity of the index.