Silicon Nozzle Research Articles

Portable rainfall simulator for plot-scale investigation of rainfall-runoff, and transport of sediment and pollutants

A low-cost, simple to use portable rainfall simulator is developed for use over a 5 m2 plot. The simulator is easy to transport and assemble in the field, thereby allowing for necessary experimental replicates to be done. It provides rainfall intensities of between 20 and 100 mm/h by changing the number and type of silicon nozzles used. The Christiansen coefficient of uniformities obtained in the field are appropriate and vary from 79 to 94% for rainfall intensities ranging from 30 to 70 mm/h. In addition, the median volumetric drop diameters measured for rainfall intensities of 30, 50, and 70 mm/h are in the lower range of that of natural rainfall and equal to 1.10±0.08, 1.69±0.21, and 1.66±0.20 mm, respectively. The velocities of the raindrops with diameters less than 1.2 mm reached terminal velocities, while raindrops less than 2.0 mm achieved velocities reasonably close to the terminal velocity of natural rainfall. Furthermore, the average time-specific kinetic energy (KET) for rainfall intensities of 30, 50, and 70 mm/h are 257.7, 760.1, and 1645.2 J/m2/h, respectively accounting for about 78.0 and 86.5% of the KET of natural rainfall for 50 and 70 mm/h rainfall intensity, respectively. The applicability of the portable rainfall simulator for herbicide transport study is investigated using two herbicides (atrazine and metolachlor); herbicide losses in runoff and sediment samples are in the ranges reported in the literature. As a percentage of the amount of herbicide applied, 5.29% of atrazine and 2.15% of metolachlor are lost due to combined water and sediment runoff. The results show that the portable rainfall simulator can be effectively used in studying processes such as pesticide runoff, infiltration mechanisms, and sediment generation and transport at a field plot scale with an emphasis on how surface characteristics such as slope and soil properties affect these processes.

Front side metallization of silicon solar cells by direct printing of molten metal

In this work, a new approach for the front side metallization of silicon solar cells is presented. Molten solder (Sn96Ag3Cu) is directly printed in a non-contact manner on solar cell precursors via StarJet technology. The StarJet technology features a pneumatically driven, heatable printhead with a reservoir of molten metal and a star-shaped silicon nozzle chip. Using this printhead, a jet of molten metal with 55 µm ± 5 µm diameter is generated and used to apply busbars as well as contact fingers on prefabricated electroplated seed layers. After deposition via StarJet, printed fingers have a minimum width of 70 µm and a mean aspect ratio of 0.94. The printed metallization is evaluated optically and electrically. Aluminum back surface field silicon solar cells with front side electroplated NiAg seed layers and StarJet metallization (busbars and fingers) show efficiencies of up to 18.1% after degradation. Solder is about 30–40 times cheaper than silver and therefore may allow cost-efficient solar cell metallization. The StarJet metallization on electroplated NiAg seed layers is fully functional and requires no additional post-processing steps. Only 6 mg of Ag per cell are consumed for the seed layer. As a proof-of-principle, a module is demonstrated, which consists of four solar cells that are metallized via StarJet.

Reliability Analysis and Linear Regression Model with Multilayer Perceptron of Sea Sand as an Abrasive in Erosion Process

A specialized form of sea sand blasting in mixing chamber with aid of compressed air, Silicon nozzle with high wear resistance was used in Abrasive Jet machining process. In this experimental investigation fine grain(100-150 micron) of sea sand were using as an abrasive material first time for erosion process. The erosion rate was depend upon variable pressure and standoff distance (SOD). The material removal rate (MRR) at different condition were calculated at empirical models two level of pressure with 35 trial was run. The analysis of 95% prediction bound of the silicon carbide has generated cubic polynomial model and R square value are 0.989 which was very closed 1. The value obtained of Material Removal Rate experimentally and after the calculation was with in the limit and percentage of error was very less. The reliability of the process found to be 0.80 using cronbach’salpha. The hardness of sea sand abrasive against targeted material which was not taken into consideration of model. It was indicated that the generated hole on glass work piece are 4.5 mm to 6 mm. In conventional erosion from some studies elaborated by using abrasive water jet machine and no detailed investigation were carried out about sea sand as an abrasive material.

Validation of Experimental Work by Using Cubic Polynomial Models For Sea Sand as an Abrasive Material in Silicon Nozzle in Abrasive Jet Machining Process

Nozzle is most important and critical part of in machining process of Abrasive Jet machine. Silicon nozzle with high wear resistance in this process. The erosion rate is depend upon variable pressure and standoff distance. In this experimental investigation sea sand is using as abrasive material first time for erosion process in Abrasive Jet machining process. The material removal rate at different condition were calculated by changing pressure and standoff distance. The study of work surface found to be 0.0289 gm/sec and at the pressure 5kg/cm2. The analysis of 95% prediction bound of the silicon carbide has generated cubic polynomial model and R square value is 0.9897 which is very closed 1. The value obtained of MRR experimentally and after the calculation is within the limit and percentage of error is very less. The relative hardness of abrasive against targeted material which is not taken into consideration of model. The depth of cutting hole type are 4mm to 6mm. on glass work piece. In contrast to conventional erosion from some studies elaborated by using abrasive water jet machine and no detailed investigation were carried out about sea sand as an abrasive material.

Enhanced Liquid Metal Micro Droplet Generation by Pneumatic Actuation Based on the StarJet Method

We present a novel pneumatic actuation system for generation of liquid metal droplets according to the so-called StarJet method. In contrast to our previous work, the performance of the device has been significantly improved: the maximum droplet generation frequency in continuous mode has been increased to fmax = 11 kHz (formerly fmax = 4 kHz). In addition, the droplet diameter has been reduced to 60 μm. Therefore, a new fabrication process for the silicon nozzle chips has been developed enabling the production of smaller nozzle chips with higher surface quality. The size of the metal reservoir has been increased to hold up to 22 mL liquid metal and the performance and durability of the actuator has been improved by using stainless steel and a second pneumatic connection to control the sheath flow. Experimental results are presented regarding the characterization of the droplet generation, as well as printed metal structures.

Numerical Analysis and Experimental Results by Silicon-Based MHz Ultrasonic Nozzles to Product of Monodisperse Droplets

Monodisperse de-ionized water droplets 4.5 μm in diameter have been produced in ultrasonic atomization using micro electro-mechanical system (MEMS)-based three-Fourier horn 1 MHz silicon nozzles. The required electrical drive power and voltage are 15 mW and 6.5 V, respectively. The nozzles measure 1.80 x 0.21 x 0.11 cm3 and can accommodate flow rate of 2 to 300 μl/min. As liquid enters the 200 μm x 200 μm central channel of the nozzle, a curved thin liquid film is maintained at the nozzle tip that vibrates longitudinally at the nozzle resonance frequency, resulting in formation of standing capillary waves on the free surface of the liquid film. As the tip vibration amplitude exceeds a threshold (critical or onset amplitude), the standing capillary waves become unstable (temporal instability) and a spray of monodisperse droplets (mist) is produced. The experimental results of resonance frequency, droplet diameter, voltage requirement and critical or onset amplitude support the predictions of the three-dimensional finite element simulation and the linear theory of capillary wave atomization mechanism.

Profiling Cys34 Adducts of Human Serum Albumin by Fixed-Step Selected Reaction Monitoring

A method is described for profiling putative adducts (or other unknown covalent modifications) at the Cys34 locus of human serum albumin (HSA), which represents the preferred reaction site for small electrophilic species in human serum. By comparing profiles of putative HSA-Cys34 adducts across populations of interest it is theoretically possible to explore environmental causes of degenerative diseases and cancer caused by both exogenous and endogenous chemicals. We report a novel application of selected-reaction-monitoring (SRM) mass spectrometry, termed fixed-step SRM (FS-SRM), that allows detection of essentially all HSA-Cys34 modifications over a specified range of mass increases (added masses). After tryptic digestion, HSA-Cys34 adducts are contained in the third largest peptide (T3), which contains 21 amino acids and an average mass of 2433.87 Da. The FS-SRM method does not require that exact masses of T3 adducts be known in advance but rather uses a theoretical list of T3-adduct m/z values separated by a fixed increment of 1.5. In terms of added masses, each triply charged parent ion represents a bin of ±2.3 Da between 9.1 Da and 351.1 Da. Synthetic T3 adducts were used to optimize FS-SRM and to establish screening rules based upon selected b- and y-series fragment ions. An isotopically labeled T3 adduct is added to protein digests to facilitate quantification of putative adducts. We used FS-SRM to generate putative adduct profiles from six archived specimens of HSA that had been pooled by gender, race, and smoking status. An average of 66 putative adduct hits (out of a possible 77) were detected in these samples. Putative adducts covered a wide range of concentrations, were most abundant in the mass range below 100 Da, and were more abundant in smokers than in nonsmokers. With minor modifications, the FS-SRM methodology can be applied to other nucleophilic sites and proteins.

Siノズルを用いたSi微粒子のミスト吐出

The novel mist-jet technology using a silicon nozzle and a silicon reflector has been developed. Ejection of water mist containing the silicon microparticles is demonstrated. Impurities of the silicon microparticles ejected on the substrate are analyzed. It has been verified for the first time that the contamination is reduced by the silicon head. The silicon pattern drawn by the head is successfully formed.

Silicon-based megahertz ultrasonic nozzles for production of monodisperse micrometer-sized droplets

Monodisperse ethanol droplets 2.4 microm and water droplets 4.5 microm in diameter have been produced in ultrasonic atomization using 1.5- and 1.0-MHz microelectromechanical system (MEMS)-based silicon nozzles, respectively. The 1.5- and 1.0-MHz nozzles, each consisting of 3 Fourier horns in resonance, measured 1.20 cm x 0.15 cm x .11 cm and 1.79 cm x 0.21 cm x 0.11 cm, respectively, required electrical drive power as low as 0.25 W and could accommodate flow rates as high as 350 microl/min. As the liquid issues from the nozzle tip that vibrates longitudinally at the nozzle resonance frequency, a liquid film is maintained on the end face of the nozzle tip and standing capillary waves are formed on the free surface of the liquid film when the tip vibration amplitude exceeds a critical value due to Faraday instability. Temporal instability of the standing capillary waves, treated in terms of the unstable solutions (namely, time-dependant function with a positive Floquet exponent) to the corresponding Mathieu differential equation, is shown to be the underlying mechanism for atomization and production of such monodisperse droplets. The experimental results of nozzle resonance and atomization frequencies, droplet diameter, and critical vibration amplitude are all in excellent agreement with the predictions of the 3-D finite element simulation and the theory of Faraday instability responsible for atomization.

Performance test of KOH-etched silicon sonic nozzles

Four types of KOH-etched silicon sonic nozzles with throat dimensions of around 90 μm are examined to unveil their discharging characteristics for 6×10 2< Re<8×10 3. With a specially designed clamping holder, the silicon nozzles are able to sustain an upstream pressure of at least 13.8×10 5 Pa. The critical back pressure ratio for choking is found to be insensitive to Re, and the largest of the four types is about 0.36. The silicon nozzle takes about 20 s to reach a stable Cd value, that is, a thermal equilibrium with sonic flow, after the flow starts. The discharge coefficients obtained in five days during two months have a scattering of only 0.02%, signifying good long-term stability.

Ultrasonic atomization using MHz silicon-based multiple-Fourier horn nozzles

Monodispersed droplets are produced in ultrasonic atomization using a microelectromechanical system-based three-Fourier horn 0.5MHz silicon nozzle 3.66×0.38×0.11cm3 in size. As water enters the 200μm×200μm central channel of the nozzle, a curved thin liquid film is maintained at the nozzle tip that vibrates at the resonance frequency of 486.5kHz, resulting in the formation of standing capillary waves on the free film surface. Temporal instability of these standing capillary waves occurs as the tip vibration amplitude exceeds a threshold, and a spray of droplets (mist) is produced. The measured droplet diameter of 7.0μm is in good agreement with the 6.7μm diameter calculated by 0.34 times the capillary wavelength.

Characterization of First‐Stage Silicon Nitride Components After Exposure to an Industrial Gas Turbine

This paper provides a summary of recent efforts undertaken to examine the mechanical properties and microstructural stability of first‐stage silicon nitride blades and nozzles after field testing in an industrial gas turbine. Two commercially available silicon nitrides, i.e., Kyocera SN282 vanes and SN281 blades, were successfully evaluated in the 100 h final phase engine test at Solar Turbines Incorporated. The turbine rotor inlet temperature was increased from 1010° to 1121°C at 100% speed during the engine test with efficiency increasing from 28.8% to 30.1%. Results of scanning electron microscopy showed that apparent materials recession still occurred during the 100 h engine test, especially in the leading and trailing edge regions where the gas pressure or velocity was the highest. The apparent material recession of the airfoils resulted from the volatilization of the normally protective silica layer, evidenced by the increased surface roughness and porous Lu2Si2O7 surface layer features. On the other hand, mechanical results generated using a ball‐on‐ring test technique showed that little strength degradation was measured after the 100 h engine test.

Thin films of a-SiGe:H with device quality properties prepared by a novel hollow cathode deposition technique

Abstract Using a novel hollow cathode plasma-jet reactive sputtering system in which an intense plasma, ignited in an Ar/H2 flow, is directed through silicon and germanium nozzles, a series of a-SiGe:H thin films have been prepared on silicon and on glass substrates. These films have been optically characterized by infrared (IR) spectroscopy, surface Raman spectroscopy and spectroscopic ellipsometry (335–1000 nm). Total hydrogen concentrations, as determined by FTIR, varied with deposition conditions and ranged from 2.5×1021 to 1.6×1022 atom cm−3 and correlated with secondary ion mass spectrometry (SIMS) elemental analyses to within 10%. The ellipsometric spectra of the films have been fitted with a modified Tauc–Lorentz model for the determination of film properties, including thickness (ranging from 400 to 1100 nm) along with film uniformity and surface roughness. Conductivity measurements in the dark and under simulated AM1 solar illumination have indicated that the films grown exhibit device-quality properties. The light-to-dark conductivity ratio has consistently been greater than 1000 for films with bandgaps down to 1.3 eV. Relationships between deposition parameters, light-and-dark conductivity properties, and chemical structural features are discussed.

Advances in Piezoelectric Ink Jet Micropumps for Precision Deposition Using Silicon Nozzles

Piezoelectric ink jet micropump devices offer the capability to precisely deposit fluids within microscopic structures. Manufacturers of flat panel displays, using light emitting polymers, have employed piezoelectric ink jet micropumps in their fabrication process to accurately and consistently place fluids within the pixel structure of displays. As an integral tool in this manufacturing process, the piezoelectric ink jet micropump must maintain tolerances necessary for adequate fluid placement in the display pixels and provide jetting operability for reliable functioning with a robustness to attain sufficient life. An industry push to increase display pixel resolution, demand for improved jetability of complex fluids, and the requirement for longer ink jet micropump service life has mandated the advancement of new technologies to meet these demands. State-of-the-art MEMS techniques have been developed to fabricate high quality silicon nozzles for these demanding applications. This paper describes how new silicon nozzle technology has been applied to a piezoelectric ink jet micropump to improve drop placement accuracy, jetting operability, and chemical resistance.

Optical and Electronic Characterization of a-SiGe:H Thin Films Prepared by a Novel Hollow Cathode Deposition Technique

ABSTRACTUsing a novel hollow cathode plasma-jet reactive sputtering system in which an intense plasma, ignited in an Ar/H2 flow, is directed through silicon and germanium nozzles, a series of a-SiGe:H thin films have been prepared on silicon and glass substrates. These films have been optically characterized by infrared (IR) spectroscopy and spectroscopic ellipsometry (335-1000nm). Total hydrogen concentrations, as determined by FTIR, varied with deposition conditions and ranged from 2.5 × 1021 to 1.6 × 1022 atom cm−3 and correlated with secondary ion mass spectrometry (SIMS) elemental analyses to within 10%. Conductivity measurements in the dark and under simulated AM1 solar illumination have indicated that the films properties are very good. The light to dark conductivity ratio has consistently been greater than 1000 for films with band gaps down to 1.3 eV.

A Novel Etching Method of Silicon Nozzle Plate Manufacture for Monolithic Inkjet Print Head

The aim of this work is to develop a novel silicon etching method in the manufacturing of a silicon nozzle plate for a monolithic inkjet print head. The nozzle plate was etched by inductively coupled plasma (ICP) etching for orifice definition and wet etching for bulk surface definition. Depth of the wet etching process for thickness deviation of nozzle plate is less than 4 &#x3BC;m and the surface roughness is less than 40 &#xC5;. After the deep wet etching step with etching depth around 370&#x3BC;m and the ICP dry etching process, electrical characteristics of the driver circuits still work normally. The etching methods on silicon nozzle plate manufacture for monolithic inkjet print head in this study provide a better surface roughness of outlet surface of nozzle plate and keep the good thickness uniformity of nozzle plate.

Deposition of high quality amorphous silicon, germanium and silicon-germanium thin films by a hollow cathode reactive sputtering system

High quality hydrogenated amorphous silicon (a-Si:H), germanium (a-Ge:H) and silicon–germanium (a-SiGe:H) thin films have been deposited by means of a d.c. hollow cathode system with magnetic field confinement. High purity single-crystal silicon and germanium nozzles were reactively sputtered in a high-density hollow cathode discharge of argon and hydrogen. This process avoids the use of the toxic and pyrophoric gases, germane and silane. The amorphous silicon thin films had light to dark conductivity ratios >10 6 with light conductivity in the 10 −5 S/cm range. The best a-Si:H films have a Tauc band gap near 1.8 eV with an atomic hydrogen concentration of approximately 14%. The growth rate was in the 2–3 μm/h range. For the a-Ge:H films the FTIR results indicate that these films have hydrogen bonding as a single atom, as did the hydrogenated silicon films. The Tauc bandgap was approximately 1.0 eV for all the germanium films. A slight photoresponse was noted for these films, which were deposited at a rate of from 2 to 6 μm/h. For the a-SiGe:H films, two hollow cathodes of single crystal Si and Ge are reactively sputtered simultaneously. A description of the complete system will be presented. The optical and electronic properties of the initial films are promising. The photoresponse is dependent upon the bandgap, i.e. the germanium content, as expected. A light to dark ratio of 2600 has been achieved for a film with a bandgap of 1.53 eV. The FTIR data indicates that SiH bonds dominate over Ge:H bonds by the absence of peaks at 570 and 1880 cm −1.

Deposition of high quality amorphous silicon, germanium and silicon-germanium thin films by a hollow cathode reactive sputtering system

High quality hydrogenated amorphous silicon (a-Si:H), germanium (a-Ge:H) and silicon–germanium (a-SiGe:H) thin films have been deposited by means of a d.c. hollow cathode system with magnetic field confinement. High purity single-crystal silicon and germanium nozzles were reactively sputtered in a high-density hollow cathode discharge of argon and hydrogen. This process avoids the use of the toxic and pyrophoric gases, germane and silane. The amorphous silicon thin films had light to dark conductivity ratios >106 with light conductivity in the 10−5 S/cm range. The best a-Si:H films have a Tauc band gap near 1.8 eV with an atomic hydrogen concentration of approximately 14%. The growth rate was in the 2–3 μm/h range. For the a-Ge:H films the FTIR results indicate that these films have hydrogen bonding as a single atom, as did the hydrogenated silicon films. The Tauc bandgap was approximately 1.0 eV for all the germanium films. A slight photoresponse was noted for these films, which were deposited at a rate of from 2 to 6 μm/h. For the a-SiGe:H films, two hollow cathodes of single crystal Si and Ge are reactively sputtered simultaneously. A description of the complete system will be presented. The optical and electronic properties of the initial films are promising. The photoresponse is dependent upon the bandgap, i.e. the germanium content, as expected. A light to dark ratio of 2600 has been achieved for a film with a bandgap of 1.53 eV. The FTIR data indicates that SiH bonds dominate over Ge:H bonds by the absence of peaks at 570 and 1880 cm−1.

Investigation of the rf and dc hollow cathode plasma-jet sputtering systems for the deposition of silicon thin films

Both rf and dc hollow cathode plasma-jet sputtering systems have been investigated for thin film semiconductor deposition. These systems were studied as a modification of the well-known rf hollow cathode plasma jet system. The aim of this modification was to provide low temperature deposition of semiconductor silicon and silicon-based alloys as thin films with these plasma jet systems. As a first step, the deposition of an already well explored, hydrogenated amorphous silicon material, a-Si:H, was chosen for experimentation. Plasma erosion of single crystal silicon nozzles in an Ar and H 2 working gas mixture was utilized for this purpose. A comparison of both dc and rf hollow cathode plasma jets has been made and correlated to the a-Si:H thin film properties. As a preliminary result, large differences between the properties of a-Si:H thin films deposited using dc and rf plasmas have been found. Monohydride Si:H composition was found for a-Si:H films fabricated using the dc plasma jet system under certain experimental conditions. However, predominantly di-hydride and multi-hydride structures and strong oxidization were found for the a-Si:H films deposited using rf plasma excitation. The sputtering efficiencies of both the rf and dc jet sources for silicon films have been found to be similar.

Microrockets for Smart Dust

This paper details the design and fabrication ofmillimeter-scale solid propellant rockets for one-timedeployment of wireless sensor platforms, known as Smart Dust.Each microrocket assembly is an integrated system, incorporatinga combustion chamber, composite propellant grain, nozzle,igniter, and thermoelectric power converter. Solid propellant isadvantageous for a millimeter-scale single-use device because ofits simple implementation, unlike liquid propellants, whichrequire a more elaborate system of pumps and valves. Thereforethe total system volume and complexity are minimized.One type of combustion chamber was fabricated in silicon;however, thermal losses to the silicon sidewalls during combustionthrough a 1.5 mm2 cross section of fuel were too high toreliably maintain a burn. Successful combustion was demonstratedin cylindrical alumina ceramic combustion chambers with thermalconductivities five times lower than silicon and cross sectionsof 1-8 mm2. Thrusts of 10-15 mN were measured forceramic rockets weighing under l g, with specific impulses up to15 s.Silicon nozzles integrated with polysilicon microheaters andthermopiles for thermal power conversion were microfabricated ina single process. Fuel ignition by polysilicon microheaterssuspended on a low-stress nitride (LSN) membrane wasdemonstrated. Microheaters require less than 0.5 W of power toignite a propellant composed primarily of hydroxyl-terminatedpolybutadiene (HTPB) with ammonium perchlorate (AP) oxidizer.They are suspended for thermal isolation through bulkpost-processing by a backside deep reactive ion etch (DRIE). Theetched hole beneath the igniter area also serves as a nozzlethrough which high-velocity combustion gases exit the rocket.Thermopiles, which generate voltages proportional to hot andcold junction temperature differentials, have been fabricated inthe same process as igniters, and span backside DRIE thermalisolation cavities. Ten-junction thermopiles produced a maximumpower of 20 µW. With potential temperature differences ofhundreds of degrees and a total of 120 thermocouple junctionsfabricated on the silicon nozzle chip, hundreds of milliwatts ofpower could feasibly be produced during the microrocket's flight andused to augment the Smart Dust power supply.