First Mode Of Operation Research Articles

Phenomenological‐based model of direct blue 2 adsorption on corncob in a fixed‐bed

AbstractThis work presents a phenomenologically based semi‐physical model (PBSM) for the liquid–solid adsorption process, which has been experimentally validated. Two modes of operation of adsorption of direct blue 2 dye (DB2) on corn cobs in a fixed bed are discussed by applying the PBSM. The first mode of operation is the typical continuous liquid flow, whereas the second is a semicontinuous mode with the recirculation of liquid leaving the column. These modes of operation were used to illustrate different ways in which the system reaches equilibrium conditions. The equilibrium distribution curve (EDC) for low DB2 concentration was reached with the best fit using the Langmuir–Freundlich model (). The local mass transfer coefficient for the solid phase was evaluated by the PBSM deduction, and subsequently, the diffusivity of the surface solid was experimentally evaluated through comparison in terms of the PBSM. Regardless of the mode of operation, surface diffusion is associated with only the nature of the adsorbent material rather than the concentration of the liquid phase. In addition, the PBSM exhibited liquid and solid concentration changes at different points in the column. Moreover, different operating curves of the process were constructed and validated, exhibiting similar results when comparing the predictions of the model and the experimental data. These findings support the strength of the constructed model, enabling its extension to other adsorbent–dye systems.

Dynamic of Mining Systems: Impact of Cl− Ion Concentration on Heap Copper Leaching Process at Industrial Scale

Analytical models are of vital importance to study the dynamics of complex systems, including the heap leaching process. In this work, a methodology to study the dynamics of copper recovery in the heap leaching by means of fit of analytical models that capture the leaching dynamics product of variations of leaching agents as a function of the feeding is proposed, establishing a first mode of operation keeping the leaching agent fixed (H2SO4) and a second operation mode, where Cl− is added to accelerate the reaction kinetics of sulfide minerals (secondary sulfides). Mineral recovery was modeled for the different modes of operation, dependent on the independent variables/control parameters time, heap height, leach flow rate, and feed granulometry. The results indicate that the recovery of ore from sulfide minerals is proportional to the addition of Cl−, reaching recovery levels of approximately 60%, very close to 65% recovery in conventional oxide leaching, using only H2SO4 as leaching agent. Additionally, high copper recoveries from sulfide ores are achieved at medium Cl− concentrations, but the increase in recovery at high Cl− concentrations is marginal.

A mobile-organic biofilm process for wastewater treatment.

The mobile-organic biofilm (MOB) process includes mobile biofilms and their retention screens with a bioreactor and liquid and solid separation. The MOB process is inexpensive and easy to integrate with wastewater treatment (WWT) processes, and it provides for high-rate WWT in biofilm or hybrid bioreactors. This paper describes three modes of MOB process operation. The first mode of operation, Mode I, has a mobile-biofilm reactor and a mobile-biofilm retention screen that is downstream of and external to a bioreactor and upstream of liquid and solid separation. Modes II and III have a hybrid (i.e., mobile biofilms and accumulated suspended biomass) bioreactor and liquid and solid separation. Mode II includes a mobile-biofilm retention screen that is downstream of and external to a hybrid bioreactor and upstream of liquid and solid separation. Mode III includes mobile-biofilm retention screening that is external to a hybrid bioreactor and liquid and solid separation, receives waste solids, and relies on environmental conditions and wastewater characteristics that are favorable for aerobic-granular sludge formation. This paper presents a mechanistic approach to design and evaluate MOB processes and describes MOB process: (1) modes of operation, (2) design and analysis methodology, (3) process and mechanical design criteria, (4) mathematical modeling, (5) design equations, and (6) mobile-biofilm settling characteristics and return. A mathematical model was applied to describe a fixed bioreactor volume and secondary-clarifier area with Modes I, II, and III. The mathematical modeling identified key differences between MOB process modes of operation, which are described in this paper. PRACTITIONER POINTS: MOB is a municipal and industrial wastewater treatment (WWT) process that reduces bioreactor and liquid and solids separation process volumes. It may operate with a mobile-biofilm reactor or a hybrid (mobile biofilms and suspended biomass) bioreactor. This paper provides a mechanistic basis for the selection and design of a MOB process mode of operation, and it describes MOB process modes of operation, design criteria, design equations, mathematical modeling, and mobile-biofilm settling characteristics. MOB integrated WWT plants exist at full scale and reliably meet their treatment objectives. The MOB process is an emerging environmental biotechnology for cost-effective WWT.

A reconfigurable narrow and wide band multi bias graphene based THz absorber

A three layers graphene-based THz absorber composed of multi-bias graphene ribbons is presented. The structure is described using equivalent circuit model and design methodology is developed via impedance matching concept. Also, relatively heavy optimization is utilized to obtain two sets of chemical potential values. Two operational behaviors are expressed corresponding to each bias set. Leveraging both equivalent circuit representation and impedance matching concept, the proposed structure is able to show both narrow multi band and wide band absorption over 0.1 THz to 5 THz frequency range. The first mode of operation can perfectly absorb THz incident waves in 0.5 THz, 1.4 THz, 2.35 THz, 3.23 THz and 4.11 THz while the second mode of operation absorbs THz incident waves between 0.5 THz to 2.5 THz as wide band response. Additionally, to investigate device dependency against geometrical parameters, electron relaxation time, chemical potentials and incident angle, ample simulations are reported for both modes of operations. Achieving both multi band and wide band absorption via a unique structure, makes the proposed device an ideal candidate to be used in optical systems and sensors for medical imaging, indoor communications and security.

Time-Varying Magnetic Field to Enhance the Navigation of Magnetic Microparticles in a Bifurcated Channel

This letter investigates the navigation of magnetic microparticles (MMPs) in a Y-shaped microfluidic channel under the influence of an external magnetic field. The external magnetic field exerts a magnetic force on the magnetizable MMPs to steer them from the bifurcation point to the desired channel. During this process, some MMPs aggregate and stick to the channel walls, thus reducing the efficacy of the navigation process. To mitigate this problem, a time-varying magnetic field (TVMF) is applied for efficient navigation of the MMPs in the channel. The TVMF alternately switches between two modes of operation described as follows. In the first mode of operation, the TVMF is applied for a certain time duration to generate the magnetic force required for steering the MMPs to the desired outlet. The second mode of operation facilitates mitigation of the stiction and aggregation of MMPs by modulating the TVMF and time duration of operation, so as to yield a lower magnetic force in the reverse direction to that in the first mode. Extensive simulations are performed to analyze the switching time for effective steering of the MMPs using COMSOL Multiphysics. Results illustrate that the time duration between the two modes of operation should be set using a ratio of 3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$:$</tex-math></inline-formula> 1 for effective guidance of the MMPs to the correct outlet.

ФУНКЦІОНАЛЬНЕ УРАЖЕННЯ РАДІОЕЛЕКТРОННИХ СИСТЕМ

Purpose: The most important problem of any state is protection of the control and management systems used for the country, national armed forces, high-risk facilities (nuclear power plants, large chemical plants, airports, etc.). Here, the fact that the means of attack can be deployed on ballistic and cruise missiles, aircraft, and drones should be accounted for. The flight altitude of these vehicles varies from ≈300 km to ≈ 10 m. Any attack vehicle is equipped with complex avionics consisting of circuit elements sensitive to electromagnetic fields. Since the 1980s, a new scientific and engineering direction has been developing, being termed as a “functional damage to avionics”. It is based on the creation of powerful means of electromagnetic radiation possessing the energetic capabilities of incapacitating avionics at significant distances (from ~ 100 m to ~ 1000 km). The purpose of this work is to analyze the possible functional damage to avionics with account for the tendencies in avionics technologies. Design/methodology/approach: The analysis is made on the capability of inflicting functional damage to avionics accounting for the modern trends in developing the powerful means of electromagnetic energy generation in the microwave and shorter wavelength ranges, miniaturization and integration of avionics circuit elements. The regression is constructed for the critical energy time dependence. It has been determined that for decades the critical energy required to damage the circuit elements shows a tendency to decrease. This is due to the further miniaturization and integration of microcircuits according to the Moore’s law, which is still valid for now. For a number of circuit elements, the critical energy is found to be in the range of 10-11–10-10 J. At the same time, a reverse tendency arises to protect avionics from being functionally damaged. In this case, the critical energy makes 10-7–10-6 J and greater. From the derived version of the basic equation of functional damage to avionics, the maximum distance at which the damage is possible with the energetics of the existing radio systems is estimated. For the ground-based facilities, this distance can attain hundreds of kilometers. For mobile vehicles, it can reach 10–100 km. Combining target detection, identification and avionics damage capabilities in one radio system has been validated and advised. The transition from the first mode of operation to the second one occurs at shorter distances with an increase of 2–3 orders of magnitude in the pulse energy. Findings: The regression equation has been obtained for the time dependence of the critical energy required for inflicting functional damage to avionics. Its constant decrease has been confirmed. Such a behavior is closely related to the Moore’s law, which characterizes the degree of miniaturization and integration of avionics circuit elements. It has been predicted that for a number of instruments the critical energy can be smaller than 10-11–10-10 J. A version of the basic equation of functional damage to avionics has been obtained. The maximum distance for a modern radio system to damage the avionics has been shown to attain many hundreds of kilometers. For the radio systems installed on mobile vehicles, this distance makes 10–100 km. Target detection, tracking and identification, as well as avionics damage capabilities, have been proved to be rationally combined in one radio system. To cause damage at a corresponding range, the pulse energy needs to be increased by a factor of 102–103. Conclusions: There are all science and technology prerequisites for developing effective radio systems inflicting functional damage to avionics and for the state defense and protection, armed forces, and high-risk facility controlling systems. Key words: functional damage; avionics; critical energy; Moore’s law; functional damage equation; radiolocation equation; detection and destruction range

Microfluidic Platform to Transduce Cell Viability to Distinct Flow Pathways for High-Accuracy Sensing.

Mechanical properties of cells such as stiffness can act as biomarkers to sort or detect cell functional properties such as viability. In this study, we report the use of a microfluidic device as a high-sensitivity sensor that transduces cell biomechanics to cell separation to accurately detect viability. Cell populations are flowed and deflected at a number of skew ridges such that deflection per ridge, cell-ridge interaction time, and cell size can all be used as sensor inputs to accurately determine the cell state. The angle of the ridges was evaluated to optimize the differences in cell translation between viable and nonviable cells while allowing continuous flow. In the first mode of operation, we flowed viable and nonviable cells through the device and conducted a sensitivity analysis by recording the cell's total deflection as a binary classifier that differentiates viable from nonviable cells. The performance of the sensor was assessed using an area under the curve (AUC) analysis to be 0.97. By including additional sensor inputs in the second mode of operation, we conducted a principal component analysis (PCA) to further improve the identification of the cell state by clustering populations with little overlap between viable and nonviable cells. We therefore found that microfluidic separation devices can be used to efficiently sort cells and accurately sense viability in a label-free manner.

Technical and economic evaluation of different operating modes for mechanized fertilizer application in coffee plantations

The present study aimed to investigate the performance parameters and related costs of a machinery set composed of a tractor and a machine for fertilizers and soil correctives application, working in a coffee yard. It was evaluated two different modes of operation. For the first mode of operation (MO1), the machinery applied the total recommended dose to only one side of the plants and traveled in only half of the plot interrows. For the second mode of operation (MO2), the machinery applied half the recommended dose to each side of the plants and traveled in all of the plot interrows. The study was performed at Bom Jardim Farm, located in the municipality of Bom Sucesso, state of Minas Gerais, Brazil. The performance parameters included effective field capacity and effective time. The hourly cost of the fertilizers and soil correctives application operation was determined based on the farm’s management data and the effective cost was obtained by relating the hourly cost and the effective time. The results showed that MO1 implies higher effective field capacity and lower effective cost, with the cost of only 50.1% of that found for MO2. Key words: Agricultural machinery management; costs; Coffea arabica L.

Research of a diametrical fan with suction channel

Various grain cleaning machines equipped with pneumatic systems are widely used for cleaning grain from impurities, in which as an air-flow generator, diametric fans are increasingly used to create a uniform airflow over the width of pneumatic systems for high-quality grain cleaning. Installation of fans of this type in the pneumatic system of grain cleaning machines in some cases entails the creation of guiding elements in front of its intake part. A diametric fan with a suction channel located in the initial part of the spiral body and allowing it to be assembled into pneumatic systems of grain cleaning machines without additional or special taps has been developed. Theoretical and practical studies have been carried out to determine the depth Δh of the suction channel. It is established that the most rational value of the depth Δh of the suction channel is 0.05 m for a fan with an outer diameter D2 of the impeller 0.30 m. The fan has three operating modes. With the suction canal open, suction of dusty air from the sludge chambers, dust catchers or unloading devices of the air systems (the first mode of operation of the fan) or the air flow into the dust-collecting channel can occur along it to avoid precipitation of impurities in it or to a certain working area where it is necessary to separate the forage grain from light impurities (second mode of operation of the fan). The third operating mode of the fan with the suction channel closed ensures that the air flow is only supplied to the delivery pipe.

SAEB: A Lightweight Blockcipher-Based AEAD Mode of Operation

Lightweight cryptography in computationally constrained devices is actively studied. In contrast to advances of lightweight blockcipher in the last decade, lightweight mode of operation is seemingly not so mature, yet it has large impact in performance. Therefore, there is a great demand for lightweight mode of operation, especially that for authenticated encryption with associated data (AEAD). Among many known properties of conventional modes of operation, the following four properties are essential for constrained devices:&#x0D; &#x0D; Minimum State Size: the state size equals to a block size of a blockcipher.&#x0D; Inverse Free: no need for a blockcipher decryption.&#x0D; XOR Only: only XOR is needed in addition to a blockcipher encryption.&#x0D; Online: a data block is processed only once.&#x0D; &#x0D; The properties 1 and 4 contribute to small memory usage, and the properties 2 and 3 contribute to small program/circuit footprint. On top of the above properties, the fifth property regarding associated data (AD) is also important for performance:&#x0D; &#x0D; Efficient Handling of Static AD: static AD can be precomputed.&#x0D; &#x0D; We design a lightweight blockcipher-based AEAD mode of operation called SAEB: the first mode of operation that satisfies all the five properties to the best of our knowledge. Performance of SAEB is evaluated in various software and hardware platforms. The evaluation results show that SAEB outperforms conventional blockcipher-based AEAD modes of operation in various performance metrics for lightweight cryptography.

Performance analysis of an integrated solar-based power generation plant using nanofluids

In this present paper, a thermo-economic analysis is carried to study the performance and feasibility of using nanofluids as heating fluids in an integrated solar power generation plant (ISPGP). The integrated power generation plant consists of the solar field that is represented by parabolic trough solar collectors (PTSCs), a thermal energy storage system, and a power block. The effect of dispersing copper (Cu) and silver (Ag) nanoparticles into Therminol VP-1 and Syltherm 800 fluids is investigated. The effect of the nanofluids on the power output, energetic and exergetic efficiencies, and entropy generation of the PTSC is studied, in addition to their effect on the output performances and cost parameters of the ISPGP for 2 modes of operation. The first mode of operation assumes no storage, while the second mode of operation assumes a storage period of 7 hours. The most efficient nanofluids are selected to replace Therminol and Syltherm. Yearly, monthly, and daily analyses are carried to study the magnitude of improvement that is caused by the nanofluids on the performance of the PTSC and ISPGP. The simulation results show that the presence of the nanofluids decreased the pressure drop inside the PTSC and lowered the required pumping power. Moreover, it is established that 5% Cu/Therminol and 4% Ag/Therminol are the best replacements for Therminol for the first and second modes of operation, respectively; 5% Ag/Syltherm is the best replacement for Syltherm for both modes of operation. The monthly power output of the PTSC is increased by 11.1% and 11.7% when 5% Cu/Therminol and 4% Ag/Therminol are used, whereas an increase of 18.2% occurs when 5% Ag/Syltherm is used. The nanofluids increased the total power output of the ISPGP while decreasing the levelized cost of electricity (LEC). For instance, when comparing 5 % Ag/Syltherm with Syltherm, the annual energy output increased from 121 to 125 GWh, while the LEC decreased from 5.86 to 5.70 c/kWh. In addition, it is proven that the ISPGP performs better when the thermal energy storage system is used. For example, when Therminol is used, the annual energy output of the ISPGP increased from 123 to 208 GWh and the LEC was lowered from 5.75 to 4.11 c/kWh.

A numerically robust blind equalization scheme applied to MIMO communication systems

In this paper, we propose a numerically robust blind equalization scheme to mitigate cochannel and intersymbol interferences and separate signals from a convolutive mixture in multiple-input multiple-output (MIMO) communication systems. The robustness of the proposed scheme is achieved through a particular dual-mode operation applied to a constant-modulus-based space-time algorithm that corrects phase rotations. In the first mode of operation, the consistency in the nonlinear estimates of the transmitted signals is ensured. In the second mode, the Euclidean norms of the equalizer coefficient vectors decrease along the iterations, which allows the algorithm to return to the first mode of operation, where the estimation of the transmitted signals really occurs. In particular, we apply this scheme to a multimodulus version of the multiuser Shalvi-Weinstein algorithm (MU-SWA). By means of a deterministic stability analysis assuming the persistence of excitation condition, we show that the dual-mode MU-SWA does not diverge.

Compact Rear-Radiating Circularly Polarized Feeds for Front-Fed Reflector Antennas

Unique backward radiation properties of compact four-arm Archimedean spiral antennas are explored and investigated. Conventionally, an active zone in the order of one wavelength is required to have the spiral antenna work in its first mode of operation, producing broadside radiation patterns. In this letter, it is shown that a reflector-backed four-arm spiral antenna with a diameter of much less than the conventional active zone is capable of effectively directing the same broadside radiation into the backward region with an opposite sense of polarization. The antenna such developed is well suited as a primary feed in small front-fed parabolic reflector antennas. The circular polarization performance of the proposed antenna is investigated including the circularly polarized gain, axial ratios, beamwidths, and cross polarization. Furthermore, the performance of the compact rear-radiating antenna as a primary feed in parabolic reflector antennas is investigated, proving the promising applications of the proposed compact feeds with backward radiation patterns.

Optimal operation of battery-less solar powered reverse osmosis plant for desalination

Small RO based desalination plants driven by solar power are attractive options, especially in areas with unreliable grid power supply. Batteries or other energy storage devices can be used to buffer against the inherent variability in solar power. However, the capital and maintenance cost of batteries and problems associated with their safe disposal renders this option unattractive. The focus of this work is optimal operation of an RO plant driven by solar power without batteries under continuously varying solar radiation intensity. A model of an RO plant driven by solar power without batteries is developed and demonstrated to have adequate predictive capability. The model is used to determine optimal operation policies under two different methods of operation, namely, (i) without storage of permeate and (ii) with permeate storage. Examination of the optimal solution in the first mode of operation reveals that a simple, robust, and model free implementation strategy using active constraint control is possible. Comparison of results show that accounting for the permeate storage results in a higher permeate production, and the buffer tank can be viewed as a surrogate energy storage device.

Design and optimization of cantilever based piezoelectric micro power generator for cardiac pacemaker

Piezoelectric micro-power generator (PMPG) converts mechanical vibration energy into electric energy via piezoelectric effects. In cardiac pace makers, the use of PMPG eliminates the need for a traditional lithium iodide battery replacement. In this paper we design and optimize PMPG that is able to harvest the mechanical movement of the heart beat to be converted into usable electrical power in frequency range 1---1.7 Hz. Eight control parameters are selected: which are proof mass material, piezoelectric material, proof mass length, proof mass thickness, piezoelectric layer width, piezoelectric layer thickness, silicon nitride layer width, silicon nitride layer thickness. Orthogonal arrays of Taguchi method for these eight parameters mentioned with three levels and signal-to-noise (S/N) ratio, and ANOVA analysis is studied to determine the optimum design. COMSOL Multiphysics ver. 4.2 is used in 18 different simulations. The maximum output power and highest efficiency designed at 1.2 Hz is equivalent to 72 beat per min. Both Taguchi and ANOVA confirms the same results of determining the parameter of having the most influence on the generated output power at 1.2 Hz in descending order: which are piezoelectric material of PZT-5A, proof mass length of 5 mm, piezoelectric layer thickness of 30 µm, proof mass thickness of 4 mm, piezoelectric layer width of 0.12 mm, silicon nitride layer width of 0.16 mm, silicon nitride layer thickness of 30 µm, and proof mass material of aluminum. Eigen frequency analysis for the first six modes of operation for PMPG frequencies are: 1.2 HZ, 5.4 Hz, 6.9 Hz, 29,7 Hz, 694.8 Hz, 708.3 Hz. The first mode of operation is selected as operation mode and shows that 93 % of PMPG's total displacement and output power was produced in the range of 1---1.4 Hz, therefore PMPG can work when the heart rate between 60 and 84 bpm. Transient analysis performed at 1.2 Hz reaches the steady state before the first 10 cycles with output power density of 23.13 µW/cm3, which is suitable for powering cardiac pace maker.

Hearing Aid With Automatic Switching Between Modes Of Operation

The present invention relates to a hearing aid, especially a hearing aid with multiple modes of operation and efficient switching between these modes of operation. The hearing aid comprises means for performing a first mode of operation, means for performing a second mode of operation, first and second quality measuring means for providing first and second quality measures corresponding to the first and second modes of operation, respectively, and selecting means for automatically selecting one of said first and second modes of operation by applying a predetermined selection criterion to the first and second quality measures, and wherein the selecting means is programmed to select the mode of operation for which the estimated quality measure is largest when the difference between the first and second quality measured exceeds a predetermined threshold value.

Intermittent Energy Harvesting Improves the Performance of Microbial Fuel Cells

In this study, we compare the efficiencies of harvesting energy from microbial fuel cells (MFC) using two modes of operation: (1) continuous-passing the current through an electrical load-and (2) intermittent-first accumulating the energy in a capacitor and then discharging it through the load. Each of these two modes of operation has advantages and disadvantages: the first mode of operation allows the continuous powering of low-power-consuming devices, and the second mode of operation allows the intermittent powering of high-power-consuming devices. We used a two-compartment MFC: in the anodic compartment, Shewanella oneidensis MR-1 was grown using lactate as an electron donor, whereas in the cathodic compartment we used an electrode made of manganese-based catalyzed carbon bonded to a current-collecting screen made of platinum mesh and oxygen as the electron acceptor. The maximum power generated by harvesting energy intermittently was 152 microW, which is 111% higher than the 72 microW generated by harvesting the energy continuously. We conclude that in the operation of MFCs it is beneficial to harvest the energy intermittently. This not only allows the powering of external devices of high power consumption but also allows generating power with greater energy efficiency than does harvesting the energy continuously.

Avoiding Divergence in the Shalvi–Weinstein Algorithm

The most popular algorithms for blind equalization are the constant-modulus algorithm (CMA) and the Shalvi-Weinstein algorithm (SWA). It is well-known that SWA presents a higher convergence rate than CMA, at the expense of higher computational complexity. If the forgetting factor is not sufficiently close to one, if the initialization is distant from the optimal solution, or if the signal-to-noise ratio is low, SWA can converge to undesirable local minima or even diverge. In this paper, we show that divergence can be caused by an inconsistency in the nonlinear estimate of the transmitted signal, or (when the algorithm is implemented in finite precision) by the loss of positiveness of the estimate of the autocorrelation matrix, or by a combination of both. In order to avoid the first cause of divergence, we propose a dual-mode SWA. In the first mode of operation, the new algorithm works as SWA; in the second mode, it rejects inconsistent estimates of the transmitted signal. Assuming the persistence of excitation condition, we present a deterministic stability analysis of the new algorithm. To avoid the second cause of divergence, we propose a dual-mode lattice SWA, which is stable even in finite-precision arithmetic, and has a computational complexity that increases linearly with the number of adjustable equalizer coefficients. The good performance of the proposed algorithms is confirmed through numerical simulations.

Microoptical Characterization of Piezoelectric Vibratory Microinjections in Drosophila Embryos for Genome-Wide RNAi Screen

In this paper, we study the effect of acoustic agitation on the penetration force for microinjections in Drosophila embryos for genome-wide RNA interference (RNAi) screens, using an integrated optical MEMS force encoder for in vivo characterization of the dynamic penetration forces. Two modes of operation are investigated. In the first mode of operation, the injector is brought into contact and acts on the embryo with a fixed force, and the vibration amplitude of the microinjector is increased till penetration occur. We observed a linear decrease in the penetration force of 1.6 /spl mu/N with every 0.1 m/s tip velocity increase. In the second mode of operation, the vibration amplitude is kept constant and the injector is pushed into the embryo until penetration. We simulate the optical force encoder eigenmodes and measure the injection force over the frequency range from 0 to 16 kHz with actuation voltages up to 150V. Among the eight encoder eigenmodes with resonant frequency up to 16 kHz, the longitudinal vibration along the injector is shown to dominate the force reduction at 14 kHz. Two other modes, both involving significant out-of-plane injector motion, reduce the penetration force by 52% around 3.1 kHz. The average penetration force is calculated based on injections into multiple embryos for each experimental condition. For each microinjection, the peak (or average) penetration force can be derived from the peak (or average) relative displacement of the two gratings upon penetration. The achieved minimum peak penetration force was 15.6 /spl mu/N (/spl sim/29.7% of the static penetration force), while the minimum average penetration force was 2.7 /spl mu/N (5.1% of the static penetration force).

Interferometric synthetic sonar antenna

The invention relates to an interferometric synthetic sonar antenna. It consists in processing the signals coming from the sensors of two superimposed parallel arrays ( 101,102 ) forming the reception antenna, these two arrays being offset by a half-pitch between sensors, relative to each other and parallel to themselves. In a first mode of operation, the signals of the two arrays are processed to form a single synthetic antenna having a higher resolution in bearing than that of the two synthetic antennas of the interferometric mode. In a second mode of operation, the signals of the two arrays are processed jointly in the auxiliary transmission frequency bands, enabling the the two synthetic antennas to be self-calibrated with improved precision.