Sonar Transducer Pulse Calibration System

: A portable measurement system for determination of the hydrogen concentration in steels has been developed under contract with the Naval Air Development Center (NADC). This system which is based on the electrochemical permeation technique consists of the barnacle cell, so called because of its magnetic attachment to steel surfaces, and the electronic measurement system. Three prototypes of the combined system have been delivered to NADC. This report contains a description of the barnacle cell and the measurement system including all drawings for the cell components and for the electronic circuits. Complete descriptions of the operating procedures are included. Experimental results obtained with the combined system on 4130 steel and cadmium plated 4340 steel obtained from NADC are presented. (Author)

General Construction Supplies & Services (MIC: SIC: 7359 NAIC: 532490)McGrath RentCorp is a rental company with two rental products; relocatable modular buildings and electronic test equipment. Co. operates through three business segments: Mobile Modular Management Corporation (MMMC), its modular building rental division; TRS‐RenTelco, its electronic test equipment division; and Enviroplex, Inc., its subsidiary classroom manufacturing business selling modular buildings used primarily as classrooms in California. MMMC rents and sells modular buildings and accessories to customers in California, Texas, Florida, North Carolina and Georgia, while TRS‐RenTelco rents and sells electronic test equipment nationally and internationally.

This paper is a survey of methods of high-impulse current and voltage measurement. Typically, such measurement techniques must now include capabilities for measuring high-energy impulses having peak powers as high as many megawatts, currents as high as many mega-amperes, or voltages as high as several megavolts, with rise times as short as a fraction of a microsecond (even as short as the subnanosecond range for moderately high-energy impulses). These capabilities had to be attained in recent years to meet the needs of various areas of scientific research employing such high-energy impulses. This represents a significant extension in the state of the art of such measurement techniques beyond their more traditional role in development and testing of high-voltage bulk power system equipment. The three most commonly used methods of high-impulse current measurement are the magnetic probe, current transformer, and "pure" resistive shunt methods. These methods are treated in considerable detail. High-voltage capacitive dividers, resistive dividers, and reflection-type attenuators are covered as the principal methods of high-impulse voltage measurement, with some added discussion of the means of insulating such devices. A brief description is given of schemes involving use of laser light sources to measure high-impulse currents and voltages by means of magnetooptic and electrooptic effects. Diagnosis of the complete properties of high-power pulses is also discussed. The emphasis throughout the paper is on a review directed toward practical measurement considerations and techniques.

General Construction Supplies & Services (MIC: 3.3 SIC: 7359 NAIC:532490)McGrath RentCorp is comprised of three business segments: Mobile Modular Management Corporation (MMMC), its modular building rental division; RenTelco, its electronic test equipment rental division; and Enviroplex, its 81.0%‐owned portable classroom manufacturing business. MMMC rents and sells modular buildings and accessories to fulfill customers' temporary and permanent space needs in California and Texas. RenTelco rents and sells electronic test equipment nationally from its two locations in Plano, TX and Livermore, CA. Enviroplex sells its portable classrooms directly to the California public school districts.

General Construction Supplies & Services (MIC: 3.3 SIC: 7359 NAIC: 532490)McGrath RentCorp is comprised of three business segments: Mobile Modular Management Corporation (MMMC), its modular building rental division; RenTelco, its electronic test equipment rental division; and Enviroplex, its 81.0%‐owned portable classroom manufacturing business. MMMC rents and sells modular buildings and accessories to fulfill customers' temporary and permanent space needs in California, Texas and Florida. RenTelco rents and sells electronic test and measurement equipment nationally and internationally from its Dallas, TX and Montreal, Canada facilities. Enviroplex sells its portable classrooms directly to the California public school districts.

Efficient collection of acid and chemical mists at high gas velocities has been obtained by the development of equipment that will function mechanically at gas flow rates to 850 feet per minute. The collector, designed for multi-stage operation uses a concurrent liquid wetting system with counter-current stage operation. Numerous conditions affecting performance were explored such as selection of suitable gas sampling equipment and controlled chemical feeding procedures. The investigation included studies with the following acids: Sulfuric, hydrochloric, perchloric, acetic, phosphoric and chromic—as well as ammonia, chlorine gas, ethyl enediamine and nitrogen dioxide.

12 - Measurands and measurement equipment

The results of the development of an automated diagnostic setup for measuring the non-uniformity of the photoresponse of solar cells using the Standard Commands for Programmable Instruments (SCPI) language are presented. SCPI is a standard syntax and commands for use in controlling programmable testing and measuring devices, such as automatic test equipment and electronic test equipment.

Research in the field of high-power, low-frequency underwater transducers has been sustained by advances in submarine noise reduction and the promise of long-range detection at low frequencies. The earliest idea came up to use the already available passive towed array sonars as receive arrays in conjunction with additionally towed sound sources. The frequency of the active adjunct idea was of course given by the existing passive arrays. Very promising trials at sea, even in the shallow water environment, soon led to the consideration of full low-frequency active sonar systems (LFASS). Those have now been investigated for nearly two decades. With the emergence of new high-power transduction materials and the rapid evolution of fast computers and powerful modeling techniques, this research field has been fertile ground for transduction innovation. Specifically, high-power transducer developments include performance improvements to conventional piezoelectric ceramic projectors, progress in the exploitation of new active driver materials, and advances in transduction design techniques. While high power, low frequency, wide bandwidth, and high efficiency remain the primary performance objectives behind these developments; low weight, small size as well as medium to deep submergence are desirable physical attributes that require equal attention by the designer. This paper emphasizes the key characteristics of two sea-proven concepts for LFASS: Janus Helmholtz transducers and multihead arrays (international patents). The attention will be particularly focused on measured values of the sound sources. Finally, this paper addresses future trends in terms of sonar array designs for LFASS.

As a possible alternative to spectral analysis of biological processes the method of thresholding the recorded function is reconsidered. The frequencies of the section length for a finite set of levels form the frequency surface which is the starting point for inference and reasoning. The paper presents ideas and examples to stimulate the development and use of a suitable electronic equipment.

Abstract. Sub-10 nm aerosol particles play a critical role in the atmosphere through their involvement in new particle formation, a key process influencing the availability of cloud condensation nuclei. In recognition of their significance, international observation frameworks such as the Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS) engage in the process of integrating their observations into standardized protocols. ACTRIS aims to enhance the understanding of atmospheric processes, including those related to particle dynamics and their interactions with clouds and climate through harmonized long-term observations. To evaluate the performance of current instrumentation for sub-10 nm particle measurements, as well as the procedures for doing so, in November 2023, the ACTRIS Cluster Calibration Center in Helsinki, Finland, held its first workshop on the intercomparison of instrumentation for sub-10 nm aerosol particle number size distribution measurements. In this workshop, three mobility-based systems (GRIMM PSMPS, TSI 1 nm SMPS and TSI 3938N56) and five activation-based systems (three Airmodus A11s and two Airmodus A12s) were evaluated. The focus lay on assessing their number concentration response and size-dependent detection efficiency – including the determination of the diameter with 50 % detection efficiency – and sizing accuracy. In addition to these parameters, the instruments were compared with each other while measuring aerosol particle number size distributions side by side from an aerosol chamber. Beyond the evaluation of instrument performance, the workshop aimed to test and assess calibration and comparison methods to identify aspects of ACTRIS compliance requiring further refinement. Although this work highlights the key strengths of the different measurement techniques and instruments, several challenges remain. Mobility-based systems showed high sizing accuracy, especially for particles larger than 2 nm, while encountering challenges in measuring particles in the lower atmospheric concentration range. Activation-based systems proved more sensitive at lower particle number concentrations and particle sizes, with the drawback of slight unit-to-unit variability. Additionally, a systematic size shift was identified in aerosols generated by 4-way-cross glowing wire generator setups, indicating a need for further investigation on this effect and the development of calibration equipment in the sub-10 nm size range.

Do you feel it now? Route of administration and Δ9-tetrahydrocannabinol-like discriminative stimulus effects of synthetic cannabinoids in mice

: The design and development of a low-pressure storage system for the storage of liquid oxygen, the conversion of the liquid to usable, gaseous state, and the controlled delivery of the gaseous oxygen under omnigravic conditions, are studied. The program was an extension of the feasibility study of a system employing an internal relief valve, and provided for, in particular, the minimization of evaporation loss of stored liquid oxygen through standby venting caused by heat leakage to the stored liquid, and the development of suitable fluid capacity gauging equipment. An account is presented of the design and development of a subcritical liquid oxygen storage and conversion system and outlines the final engineering conclusions and recommendations.

This paper studies the layout and material development of sports facilities in the plateau environment of Gansu Tibetan Plateau by means of literature data, GIS spatial analysis and mathematical statistics. Based on the correlation analysis between population size and community area, it is concluded that the population size and community area of Gansu Tibetan areas are unreasonable; the number of public sports facilities in urban communities is not coupled with the community area; the layout of sports facilities is unreasonable and the number is biased. Strategies based on GIS system: strengthen the rational layout of sports facilities; focus on equipment research and development, combine regional characteristics, and manufacture suitable sports equipment; use composite reinforcement materials to improve the controllability of local mass fitness.

Details are given of an underwater transducer which is tunable over the frequency range 250 kHz to 700 kHz. The structure comprises a pair of 50 mm-diameter lead zirconate titanate ceramic plates suitably mounted. The resonant frequency of the structure is electronically controlled by varying in a predetermined manner the amplitude and phase of the voltage applied to one of the ceramics.