The New Wuqing 70 m Radio Telescope and Measurements of Main Electronic Properties in X-band

The new Wuqing 70 m radio telescope is firstly used for the downlink data reception in the first Mars exploration mission of China, and will be used for the other deep space communications and radio astronomical observations in the future. The main specifications and measurement results of some properties in X-band are introduced in this paper, such as pointing calibration, gain and efficiency, system noise temperature, system equivalent flux density, and variations with elevation. The 23 parameters pointing calibration model considering the atmospheric refraction correction in real time is presented in the telescope, and the pointing accuracy is reached 5.70″ in azimuth direction and 6.07″ in elevation direction respectively for different weather condi-tions. More than 62% efficiencies are achieved at full elevation range, and more than 70% in the mid-elevation. The system equivalent flux density of X-band in the mid-elevation is reached 26 Jy.

CASSEGRAIN TYPE DUAL-REFLECTOR ANTENNA CALCULATION METHOD

Предложен способ расчета двухзеркальной антенны Кассегрена, отличающийся введением виртуального дополнительного облучателя для повышения точности расчетов направленных свойств и шумовой температуры. Приведен пример расчета антенны. A method for calculating a two-reflector Cassegrain antenna is proposed, characterized by the introduction of a virtual additional irradiator to increase the accuracy of calculations of directional properties and noise temperature. An example of the antenna calculation is given.

DESCRIPTION OF WORKING ENVIRONMENT SANITATION IN THE OFFICE BUILDING OF THE WARSHIP DIVISION PT PAL INDONESIA (PERSERO)

ABSTRACTSanitation is a public health effort that emphasizes mastery of various environmental factors that affect the degree of human health. Agencies that have a good and comfortable work environment will support improved performance for their employees. This study aimed to identify the description of working environment sanitation in the warship division office building at PT PAL INDONESIA (PERSERO). This research was observational. From the entire office space in the Warship Division, the five rooms with the most employees were selected for this research. The research instrument was an observation sheet with variables of building facilities, water supply, toilet, disease vector, lighting, noise, temperature, and humidity. Data analysis was performed descriptively with scoring. The results showed that four out of the five rooms (80%) that were observed had poor sanitation because they had a score of less than 75%. The results showed that the variables that were included in the criteria of lack of sanitation were toilets, lighting, temperature, and humidity. Suggestions given for the company are for building facilities, water supply, noise, and disease vector to be maintained because they are included in good sanitation criteria. Toilets, lighting, temperature, and humidity need to be fixed immediately, and reported to the officer responsible if things that can reduce the quality of office sanitation are observed. Keywords: sanitation, indoor air quality, work environment

METHOD FOR CALCULATING A TWO-MIRROR ANTENNA OF THE GREGORY TYPE

Предложен способ расчета двухзеркальной антенны Грегори, отличающийся введением виртуального дополнительного облучателя для повышения точности расчетов шумовой температуры. Приведен пример расчета антенны. A method for calculating a two-mirror Gregory antenna is proposed. The method is characterized by the introduction of a virtual additional irradiator to increase the accuracy of noise temperature calculations. An example of the antenna calculation is given.

Evaluation of PM2.5 Particulate Matter and Noise Pollution in Tikrit University Based on GIS and Statistical Modeling

In this paper, we assess the extent of environmental pollution in terms of PM2.5 particulate matter and noise in Tikrit University, located in Tikrit City of Iraq. The geographic information systems (GIS) technology was used for data analysis. Moreover, we built two multiple linear regression models (based on two different data inputs) for the prediction of PM2.5 particulate matter, which were based on the explanatory variables of maximum and minimum noise, temperature, and humidity. Furthermore, the maximum prediction coefficient R2 of the best models was 0.82, with a validated (via testing data) coefficient R2 of 0.94. From the actual total distribution of PM2.5 particulate values ranging from 35–58 μg/m3, our best model managed to predict values between 34.9–60.6 μg/m3. At the end of the study, the overall air quality was determined between moderate and harmful. In addition, the overall detected noise ranged from 49.30–85.79 dB, which inevitably designated the study area to be categorized as a noisy zone, despite being an educational institution.

A Millimeter-Wave 4th-Harmonic Schottky Diode Mixer with Integrated Local Oscillator

In this paper the design and experimental validation of a fourth-harmonic mixer based on Schottky diodes working around 300 GHz is presented. The main novelty of this work consists in the integration of an MMIC-based local oscillator, working around 75 GHz, and a mixer in the same metallic block housing. A prototype has been characterized using the Y-Factor method and yields a best measured conversion loss and an equivalent noise temperature of 14 dB and 9600 K, respectively. This performance is comparable to the state-of-the-art for this type of mixer.

Electrical Signal Modeling in Cochlear Implants. Study of Temperature and Humidity Effects

The present paper discusses the climatic effects of humidity and temperature on cochlear implant functioning and the quality of the electrical sound signal. MATLAB Simulink simulations were prepared, offering insights into signal behavior under such climatic parameter changes. A simulation setup of the cochlear implant was developed, where a source type selection was used to change between a voice recording and a “chirp” sound. In addition, a DC blocking filter was applied to the input signal. A simulation code, with the application of the climatic influence via the air attenuation function, was developed. Thereby, the attenuation of temperature and humidity in the sound atmospheric circulation of the input signal, at T = 0 °C and RH = 0% and at T = 36 °C and RH = 40% was graphically represented. The results of the electrical pulse generator for each of the eight channels, with the IIR filter, Gaussian noise, temperature variation, humidity influence, and control of denoise block activity, were thus obtained.

Analysis and Performance Assessment of a Real-Time Correction Pseudo-Correlation Microwave Radiometer for Medical Applications

A new configuration of a pseudo-correlation type radiometer is proposed for a microwave biomedical application, such as diabetic foot neuropathy. The new approach as well as its simulated performance are thoroughly assessed using commercial off-the-shelf components and custom designed subsystems. We configured a pseudo-correlation receiver, centred at 3.5 GHz, to validate the proposal, comparing its simulated response with a measured alternative based on a 90∘ hybrid coupler pseudo-correlation prototype. We custom designed a balanced Wilkinson power divider and a 180∘ hybrid coupler to fulfil the receiver’s requirements. The proposed configuration demonstrated an improved noise temperature response. The main advantage is to enable the recalibration of the receiver through simultaneous measurable output signals, proportional to each input signal, as well as the correlated response between them.