Zero location study of the beam response of the maximum output SINR beamformer

Author(s):  
Lei Zhang ◽  
Wei Liu ◽  
Bo Peng
Author(s):  
X. Zhang ◽  
Y. Pan ◽  
T.T. Meek

Industrial microwave heating technology has emerged as a new ceramic processing technique. The unique advantages of fast sintering, high density, and improved materials properties makes it superior in certain respects to other processing methods. This work presents the structure characterization of a microwave sintered ceramic matrix composite.Commercial α-alumina powder A-16 (Alcoa) is chosen as the matrix material, β-silicon carbide whiskers (Third Millennium Technologies, Inc.) are used as the reinforcing element. The green samples consisted of 90 vol% Al2O3 powder and 10 vol% ultrasonically-dispersed SiC whiskers. The powder mixture is blended together, and then uniaxially pressed into a cylindrical pellet under a pressure of 230 MPa, which yields a 52% green density. The sintering experiments are carried out using an industry microwave system (Gober, Model S6F) which generates microwave radiation at 2.45 GHz with a maximum output power of 6 kW. The composites are sintered at two different temperatures (1550°C and 1650°C) with various isothermal processing time intervals ranging from 10 to 20 min.


1996 ◽  
Vol 5 (2) ◽  
pp. 68-72 ◽  
Author(s):  
Christine M. Rankovic ◽  
William M. Rabinowitz ◽  
Gregory L. Lof

The Audiokinetron is a device that processes music for earphone presentation to patients undergoing auditory integration training, a treatment for individuals with autism and other developmental disabilities. Intensity levels produced by the Audiokinetron were measured under realistic listening conditions with a KEMAR manikin substituted for a patient. Average levels at the eardrum were 110 dB SPL when the device was adjusted to the highest setting employed by a local, trained AIT practitioner and 118 dB SPL at the maximum setting of the device. These levels are potentially harmful to hearing and warrant further safety studies of AIT instruments and protocols.


Author(s):  
N. Golub ◽  
M. Potapova ◽  
M. Shinkarchuk ◽  
O. Kozlovets

The paper deals with the waste disposal problem of the alcohol industry caused by the widespread use of alcohol as biofuels. In the technology for the production of alcohol from cereal crops, a distillery spent wash (DSW) is formed (per 1 dm3 of alcohol – 10–20 dm3 DSW), which refers to highly concentrated wastewater, the COD value reaches 40 g O2/dm3. Since the existing physical and chemical methods of its processing are not cost-effective, the researchers develop the processing technologies for its utilization, for example, an anaerobic digestion. Apart from the purification of highly concentrated wastewater, the advantage of this method is the production of biogas and highquality fertilizer. The problems of biotechnology for biogas production from the distillery spent wash are its high acidity–pH 3.7–5.0 (the optimum pH value for the methanogenesis process is 6.8–7.4) and low nitrogen content, the lack of which inhibits the development of the association of microorganisms. In order to solve these problems, additional raw materials of various origins (chemical compounds, spent anaerobic sludge, waste from livestock farms, etc.) are used. The purpose of this work is to determine the appropriate ratio of the fermentable mixture components: cosubstrate, distillery spent wash and wastewater of the plant for co-fermentation to produce an energy carrier (biogas) and effective wastewater treatment of the distillery. In order to ensure the optimal pH for methanogenesis, poultry manure has been used as a co-substrate. The co-fermentation process of DSW with manure has been carried out at dry matter ratios of 1:1, 1:3, 1:5, 1:7 respectively. It is found that when the concentration of manure in the mixture is insufficient (DSW/manure – 1:1, 1:3), the pH value decreases during fermentation which negatively affects methane formation; when the concentration of manure in the mixture is increased (DSW/manure – 1:5, 1:7), the process is characterized by a high yield of biogas and methane content. The maximum output of biogas with a methane concentration of 70 ± 2% is observed at the ratio of components on a dry matter “wastewater: DSW: manure” – 0,2:1:7 respectively. The COD reduction reaches a 70% when using co-fermentation with the combination of components “wastewater: DSW: manure” (0,3:1:5) respectively.


2020 ◽  
Vol 21 (1) ◽  
pp. 81-90
Author(s):  
Marthen Robinson Pellokila

ABTRACT Efficiency is one of the important indicators to assess the performance of a company or farm. Efficiency guarantees the use of certain inputs to achieve maximum output levels (technical efficiency) and also efficiency ensures the use of certain inputs that maximize profits (price efficiency or allocative efficiency). This article discusses the application of the estimation of price efficiency / allocative efficiency of the use of production inputs in bean farming using the linearized Cobb-Douglas Production function. The results of the analysis shows that the application of price efficiency estimation for production inputs using the Cobb-Douglas production function is satisfactory as long as the classical assumptions required by the multiple regression are fulfilled. Of the five production inputs included in the model, only one production input provides a significant value to production, namely the production input for the land area use. Thus, only the production input for land area use is estimated at the value of its price efficiency. Based on the results of the analysis, it is found that the use of production inputs for land area use has not yet reached its price efficiency.


2017 ◽  
Vol 18 (2) ◽  
pp. 68
Author(s):  
Made Padmika ◽  
I Made Satriya Wibawa ◽  
Ni Luh Putu Trisnawati

A prototype of a wind power plant had been created using a ventilator  as a generator spiner. This power plant utilizes wind speed as its propulsion. Electricity generated in the DC voltage form between 0 volts up to 7.46 volts. The MT3608 module is used to stabilize and raise the voltage installed in the input and output of the charging circuit. For instrument testing, the wind speed on 0 m/s up to 6 m/s interval used. Maximum output of this tool with a wind speed of 6 m/s is 7.46 volts.


2021 ◽  
Vol 19 (4) ◽  
pp. 383-391
Author(s):  
Chenxi Zhao ◽  
Yupeng Xing ◽  
Wei Lv ◽  
Juhui Chen ◽  
Xiaogang Liu ◽  
...  

Abstract It is being considered to pyrolyze lignin-rich biomass samples (hazelnut shells, HSs) into bio-fuels and chemicals to solve energy shortages and environmental concerns, volatile products (including liquid products and gas products) were produced and characterized from HSs pyrolysis at 400–1000 °C. With the temperature increases, the maximum output of liquid products was up to 35.79% produced at 700 °C, gas products yields increased from 21.82 to 55.46%. Gas chromatography and mass spectrometry (GC–MS) study indicated that liquid products from HSs riched in phenolic compounds, exceed 42% of liquid products and increased as the temperature rises. The application experiment showed that HSs liquid products had a significant role in antioxidant activity, and revealed that not limited to phenols, all compounds containing phenolic hydroxyl structure act as antioxidant. Composition analysis of gas products showed that more combustible gases were produced at the higher temperature, resulted in the significant increase in gas products higher heating value (HHV) from 6.21 to 24.36 MJ/kg.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pashupati R. Adhikari ◽  
Nishat T. Tasneem ◽  
Russell C. Reid ◽  
Ifana Mahbub

AbstractIncreasing demand for self-powered wearable sensors has spurred an urgent need to develop energy harvesting systems that can reliably and sufficiently power these devices. Within the last decade, reverse electrowetting-on-dielectric (REWOD)-based mechanical motion energy harvesting has been developed, where an electrolyte is modulated (repeatedly squeezed) between two dissimilar electrodes under an externally applied mechanical force to generate an AC current. In this work, we explored various combinations of electrolyte concentrations, dielectrics, and dielectric thicknesses to generate maximum output power employing REWOD energy harvester. With the objective of implementing a fully self-powered wearable sensor, a “zero applied-bias-voltage” approach was adopted. Three different concentrations of sodium chloride aqueous solutions (NaCl-0.1 M, NaCl-0.5 M, and NaCl-1.0 M) were used as electrolytes. Likewise, electrodes were fabricated with three different dielectric thicknesses (100 nm, 150 nm, and 200 nm) of Al2O3 and SiO2 with an additional layer of CYTOP for surface hydrophobicity. The REWOD energy harvester and its electrode–electrolyte layers were modeled using lumped components that include a resistor, a capacitor, and a current source representing the harvester. Without using any external bias voltage, AC current generation with a power density of 53.3 nW/cm2 was demonstrated at an external excitation frequency of 3 Hz with an optimal external load. The experimental results were analytically verified using the derived theoretical model. Superior performance of the harvester in terms of the figure-of-merit comparing previously reported works is demonstrated. The novelty of this work lies in the combination of an analytical modeling method and experimental validation that together can be used to increase the REWOD harvested power extensively without requiring any external bias voltage.


2021 ◽  
Vol 6 (3) ◽  
pp. 111
Author(s):  
Sherry Zhang ◽  
Isabella Lopez ◽  
Bernard Washington ◽  
Brittney Gaudet ◽  
Carina A. Rodriguez ◽  
...  

In adults, data support the utility and acceptance of home HIV testing; however, in youth, particularly in the US, this has not been well studied. In this exploratory study, we surveyed Tampa Bay youth aged 16−27 and attending sexual health clinics between 1 June and 31 June 2018 (n = 133) regarding attitudes and perceptions towards HIV self-testing. While most indicated the clinic over home when asked for preferred testing location, study population and subgroup analysis demonstrated a positive response (agree) to Likert-scale questions regarding the use of home HIV self-testing kits and negative responses (strongly disagree) to “would not use self-testing kit”. There was a significant difference between genders in testing location preference (p = 0.031) for those respondents that specified gender (n = 123), with males more likely to prefer home testing than females. This study suggests an openness of youth towards HIV home testing that could help to expand the number of youth aware of their HIV status.


Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3861
Author(s):  
Jie Mei ◽  
Qiong Fan ◽  
Lijie Li ◽  
Dingfang Chen ◽  
Lin Xu ◽  
...  

With the rapid development of wearable electronics, novel power solutions are required to adapt to flexible surfaces for widespread applications, thus flexible energy harvesters have been extensively studied for their flexibility and stretchability. However, poor power output and insufficient sensitivity to environmental changes limit its widespread application in engineering practice. A doubly clamped flexible piezoelectric energy harvester (FPEH) with axial excitation is therefore proposed for higher power output in a low-frequency vibration environment. Combining the Euler–Bernoulli beam theory and the D’Alembert principle, the differential dynamic equation of the doubly clamped energy harvester is derived, in which the excitation mode of axial load with pre-deformation is considered. A numerical solution of voltage amplitude and average power is obtained using the Rayleigh–Ritz method. Output power of 22.5 μW at 27.1 Hz, with the optimal load resistance being 1 MΩ, is determined by the frequency sweeping analysis. In order to power electronic devices, the converted alternating electric energy should be rectified into direct current energy. By connecting to the MDA2500 standard rectified electric bridge, a rectified DC output voltage across the 1 MΩ load resistor is characterized to be 2.39 V. For further validation of the mechanical-electrical dynamical model of the doubly clamped flexible piezoelectric energy harvester, its output performances, including both its frequency response and resistance load matching performances, are experimentally characterized. From the experimental results, the maximum output power is 1.38 μW, with a load resistance of 5.7 MΩ at 27 Hz, and the rectified DC output voltage reaches 1.84 V, which shows coincidence with simulation results and is proved to be sufficient for powering LED electronics.


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