Glass Micro Research Articles

On process stability and sustainability of controlled-Electro Chemical Discharge Machining (ECDM)

ABSTRACT To mitigate the transmission losses, glass vias have the potential to replace silicon vias in wireless transmission systems. In the wake of limitations of the existing methods, ECDM is an evolving process for glass micro drilling. However, the process control of ECDM is compromised due to variation in electrolytic conditions in terms of concentration and temperature. As a result, poor stability and sustainability hampers the commercial viability of the ECDM process. Therefore, present communication attempted to enhance the stability and sustainability of the ECDM with a novel approach and termed as controlled-ECDM. Subsequently, the process stability (real time based) of the controlled-ECDM has been compared with basic-ECDM using the user’s preference rating and I-MR chart. The results indicated a 20.65% gain in overall stability by controlled-ECDM. Additionally, the assessment of electrolyte emissions and performance on the radar graph indicated an improvement in the sustainability of the process.

Vertical Interconnection Technology for RF MicroSystem Packaging.

In this work, 1.5-level interconnections of RF microsystems with good RF performance, integration process compatibility, and high reliability are developed to meet the future demand for wireless communication microsystems in the millimeter wave band. Numerical models of 1.5-level interconnections based on solder balls with different diameters are established and analyzed using HFSS. The optimized structure parameters of 0.2 mm diameter Sn96.5Ag3Cu0.5 (SAC305) solder balls and 0.3 mm diameter Sn63Pb37 solder balls are selected for the interconnection between glass micro substrates and silicon micro substrates and between silicon micro substrates and HTCC substrates, respectively. Integration process parameters of the vertical interconnection are optimized. The micro substrate interconnection samples manufactured based on optimized integration methods and parameters show high reliability.

A green and precision compound machining method for glass micro components – Ultrasonic assisted electrochemical discharge grinding with multi-hole tube electrode

Glass is a widely used material in key fields such as Micro-Electro-Mechanical Systems (MEMS) due to its excellent properties. The existing non-traditional glass machining methods have problems such as high pollution, difficult operation, and poor sustainability, this article utilizes the effective combination of electrochemical discharge machining and grinding (named electrochemical discharge grinding, ECDG), by using NaHCO3 solution as electrolyte to achieve green machining. Utilizing ultrasonic vibration and multi-hole tube electrode to achieve precise and stable machining. Modeling and simulation analysis were conducted on the material removal rate and grinding force during the machining process, which profoundly revealed the joint improvement mechanism of spark discharge and ultrasonic vibration on grinding quality. First, a single factor experiment was used to preliminarily determine the machining threshold. Second, the Plackett-Burman experiment was used to screen key machining parameters. Then, Box-Behnken experiment was conducted on key machining parameters, and multi-objective and multi-factor optimization was performed to obtain the optimal combination of machining parameters. Compared with normal ECDG with cylindrical grinding electrode, the overcut is reduced by 8.3 %, the edge damage is reduced by 17.5 % and the surface roughness value is reduced by 70.6 %. Finally, by using the optimized combination of machining parameters, high-quality and stable machining of typical microchannel structures was achieved. The milling depth of the microchannel is 400 µm. The machining width is 1175 ± 5 µm. The surface roughness of the measurement area is 0.375 µm. The green, high-quality and stable machining of micro glass micro components further demonstrates the potential application of this compound technology.

Multi-objective optimization of hot embossing process for high-quality glass micro gratings

This study proposed a multi-objective optimization strategy to produce high-quality glass micro gratings. The applied methods include factor screening, surface response methodology (RSM), non-dominated sorting genetic algorithm (NSGA-II) and decision-making. Specifically, the significant factors were selected among several process parameters in hot embossing through screening experiments. Afterward, the regression models for the transferred ratio, uniformity of glass microstructures and warpage concerning those significant process parameters were established. Meanwhile, the significance of selected factors and their interactions was analyzed. Based on the regression models, the Pareto front was obtained by using NSGA-II program, where the top 10 solutions were applied in glass hot embossing. Finally, a decision-making strategy was employed to further choose a feasible solution that allows the fabrication of glass micro gratings with a high transfer ratio, high uniformity, low warpage, low surface roughness, and no defect. The experimental results indicated that embossing temperature has the most significant effect on the replication accuracy of glass micro gratings, followed by embossing force and embossing time. However, warpage was not significantly sensitive to any process parameters in this hot embossing process. The defect-free glass micro gratings could be eventually fabricated under the optimal process parameters, achieving a transfer ratio and uniformity of higher than 95 % and 83 %, respectively. Moreover, their Ra surface roughness and warpage can be lower than 13 nm and 1.5 μm. The satisfactory quality of embossed micro gratings revealed that the proposed multi-objective optimization strategy is feasible in glass hot embossing.

Glass micro welding in thermal accumulation regime with using spatially shaped ultrafast laser

Glass micro welding in thermal accumulation regime with using spatially shaped ultrafast laser

Thermal buckling behavior of 3D printed foams: Plain, graded, and sandwich variants

The present work focuses on the experimental investigation of the thermal buckling response of 3D printed functionally graded glass micro balloon (GMB) reinforced high density polyethylene (HDPE) composites and their respective sandwiches under non-uniform heating conditions. The influences of GMB loading and its graded composition on temperature distribution are analyzed. The reinforcement of hollow GMB rendered lower thermal conductivity due to enhanced thermal resistance with an increase in filler percentage. An increased thermal buckling strength is also observed. Due to their non-uniform thermal expansion, functionally graded sandwich beams exhibited less deflection than plain beams. Among the cases of three heating conditions (One end heating: case-1, Center heating: case-2, both end heating: case-3), maximum deflection is observed in case 2 while the minimum deflection is noted in case 1. These printed foams can be utilized for lightweight thermal insulating pipes.

A novel hot embossing process for producing high-quality glass micro-pillar arrays

Hot embossing is an efficient technology for the fabrication of glass micro- and nanostructures. However, the long cycle time, high energy consumption, and high nitrogen emissions in traditional hot embossing approach hinders sustainable production of glass micro-optics. Therefore, this paper proposes a novel two-stage gravity-assisted hot embossing process that enables the fabrication of high-quality glass micro-pillar arrays in a rapid, green manner. In this approach, the two-stage gravity loading unit provides accurate force on glass preform through a simple control system, and the tailor-made heating module based on Si3N4 ceramic heaters requires an energy consumption of just 700 kJ per molding cycle. As a result, the proposed approach is featured by low energy consumption and high manufacturing efficiency. In this study, the effects of the embossing temperature, force, and time on the replication accuracy of a K9 glass micro-pillar array were investigated through a series of hot embossing experiments. Afterward, the form accuracy, uniformity of microstructures, and warpage of glass replicas under the optimal process parameters were evaluated separately. Finally, repeated hot embossing experiments were conducted to demonstrate the reproducibility of the hot embossing process. The experimental results show that embossing temperature had the most significant effect on the replication accuracy of glass micro-pillars. By optimizing the process parameters, the embossed glass micro-pillars could achieve transfer ratios of 99.00% and 95.14% in height and diameter, respectively. Moreover, the surface roughness of glass micro-pillars was less than 5 nm, and the warpage amplitude of glass replicas in a 3.9 × 3.9 mm area was smaller than 1 μm. The small discrepancy in geometric features of glass replica in the repeated trails reflects the satisfactory reproducibility of this hot embossing process on the micro and nano scales. The results indicate the strong industrialization potential of the proposed two-stage gravity-assisted hot embossing machine and hot embossing process for fabricating high-quality glass microstructures more cleanly and sustainably.

Experimental Study of Glass Fiber Reinforced Concrete Incorporating Micro Silica

The most common building material utilized worldwide is concrete. Concrete with higher compressive strength is becoming more and more in demand as the trend toward using it more widely for high rise buildings. Experimental study of glass fiber (GF) reinforced concrete incorporating micro silica was investigated in this study. The concrete is prepared by using M40 mix. GF with 12 mm length with aspect ratio of 857 is used. Four volume fractions of 0%, 0.4%, 0.8% and 1.2% by weight of cement and micro silica with 5% by weight of cement are used. The fiber is distributed randomly in all directions. The mixes were cast and tested for workability, compressive strength, flexural strength, water permeability test, drop weight Impact test, bond strength test and residual compressive strength at elevated temperature. Micro structural study is done with SEM analysis. Workability of glass fiber reinforced concrete decreased with increase in GF. Compressive strength show 12% increment whereas Flexure strength is increases 35% compare to normal concrete. Different percentages of glass fibres and micro silica have lower water penetration depths. With regard to the fire resistance test the compressive strength at elevated temperature decreases significantly. Impact resistance and bond strength of glass fiber reinforced concrete with micro silica increases with increase in fiber content. Hence, it's suggested to use glass fiber in the concrete according to use of concrete.

3D printed functionally graded foams response under transverse load

The applications of 3D printing are rapidly increasing in aerospace and naval applications. Nonetheless, 3D printing (3DP) of graded foams exhibiting property variation along the thickness direction is yet to be explored. In the current work, the different volume fractions of hollow glass micro balloon (GMB) reinforced high-density polyethylene (HDPE) composite based graded foams are 3D printed using the fused deposition modelling (FDM) technique. The bonding between successive layers and porosity distribution of these graded configurations are studied using micro-CT scan. Further, the 3D Printed functionally graded foams (FGFs) are tested for flexural response, and results are compared with numerical values. The micro-CT results showed delamination absence between the layers. In neat HDPE layers, porosity is not evident, while minor porosity creeps in the layers having the highest GMB content. Experimental results of the flexural test showed that the graded sandwiches exhibited better strength than the graded core alone. Compared to neat HDPE, the modulus of FGF-2 (H20–H40–H60) increased by 33.83%, implying better mechanical stiffness. Among all the FGFs, FGF-2 exhibited a better specific modulus. A comparative study of experimental and numerical results showed a slight deviation due to neglecting the induced porosity.

Thin Glass Micro Force Plate Supported by Planar Spiral Springs for Measuring Minute Forces.

Microforce plates are indispensable tools for quantitatively evaluating the behavior of small objects such as tiny insects or microdroplets. The two main measurement principles for microforce plates are: the formation of strain gauges on the beam that supports the plate and the measurement of the deformation of the plate using an external displacement meter. The latter method is characterized by its ease of fabrication and durability as strain concentration is not required. To enhance the sensitivity of the latter type of force plates with a planar structure, thinner plates are generally desired. However, brittle material force plates that are both thin and large and can be fabricated easily have not yet been developed. In this study, a force plate consisting of a thin glass plate with a planar spiral spring structure and a laser displacement meter placed under the plate center is proposed. The plate deforms downward when a force is exerted vertically on its surface, resulting in the determination of the applied force using Hooke's law. The force plate structure is easily fabricated by laser processing combined with the microelectromechanical system (MEMS) process. The fabricated force plate has a radius and thickness of 10 mm and 25 µm, respectively, with four supporting spiral beams of sub-millimeter width. A fabricated force plate featuring a sub-N/m spring constant achieves a resolution of approximately 0.01 µN.

Study on warpage and filling behavior of glass in non-isothermal hot embossing

Non-isothermal hot embossing has great potential in the mass production of glass micro optical components due to the relatively short heating-cooling cycle time. However, warpage was induced by the temperature gradient inside the glass replica during hot embossing, resulting in a deteriorated optical performance. Therefore, it is non-trivial to investigate the effects of process parameters on warping and filling behaviors of glass in non-isothermal hot embossing. Firstly, a high-quality microhole was fabricated on monocrystalline silicon carbide (SiC) mold by focused ion beam (FIB) lithography. By using a novel home-made gravity-assisted hot embossing machine, the geometric information (i.e., warpage and microstructures) on SiC mold was transferred into the surface of N-BK7 glass replica. The experimental results indicate that high embossing temperature enables not only the minimization of warpage but also the enhancement of microstructure replication accuracy. Furthermore, increasing embossing force enhances filling capacity but increases warpage amplitude. Interestingly, fast heating/cooling rates and short embossing time enable a small warpage as well as a high embossing efficiency. By optimizing the process parameters, especially the embossing temperature, a small warpage amplitude of 3 μm and a high transfer ratio of 99.11% were achieved, which can meet the high requirement of precision optical components.

Microscopy of Ashoka Bark and Marketed Alternates.

Introduction- Microscopic evaluation of herbal powder is the simplest method for the identification of raw materials or raw drugs. Today, many sophisticated modern research tools are available for the identification validation and authentication of plant based drugs. Ashoka (Saraca asoca) has been used traditionally in the Indian system of medicine. Internal structure (cells and tissues) of bark of the Asoka, Shal and Kastdaru have been studied through plant anatomy/histology. Material & Methods-Raw drug sample powder of all species were dipped in water and centrifuged for five minutes to soften and sedimentation. Suspended material of the sample was transferred to a clean glass micro slide and mounted. Slides were observed under axiostar plus light microscope. Results & Discussion- The Powder Microscopic method is still one of the inventive methods for validation and authentication of the raw drugs. It also helps to find out the impurities and helps in quality assessment and assurance of the drugs. Microscopic assessment of the herbal drug of Asoka (Saraca asoca Roxb. Willd) shows similarity and some dissimilarity with cells and tissues of the bark of Shal (Shorea robusta Gaertn.) and Kastdaru (Polyalthia longifolia Sonn. Thwaites) for the selection of possible alternates.

Study on micro remaining oil distribution of polymer flooding in Class-II B oil layer of Daqing Oilfield

During the implementation of chemical flooding, problems of slow decline of water cut and poor development effect appear in Class-II B oil layer of Daqing Oilfield. In this paper, photoetched glass models and micro CT-scanner technology are used for polymer flooding experiment with different molecular weight. Experiment are carried out by parallel displacement method to simulate the effect of interlayer heterogeneity on the residual oil distribution. The results of photoetched glass model displacement experiment show that under the condition of parallel displacement, the enhanced oil recovery of low permeability model is the largest when the molecular weight of polymer solution is 1900 × 104 Da, and the overall displacement efficiency is the best. However, the compatibility between polymer solution with molecular weight of 2500 × 104 Da and low permeability model is poor. The variations in cluster residual oil saturation is lower in low permeability model, whereas other types of residual oils are higher. Micro CT-scanner results show that there is almost no membrane and blind end residual oils after polymer flooding, which validates the low utilization ratio of membrane and blind end residual oils saturation in photoetched glass model.

Статистический подход к описанию напряженного состояния микроструктуры сферопластика

Object and purpose of research. The object of research is a composite material of the syntactic foam type (SF), which forms a heterogeneous medium consisting of a polymer matrix filled with spherical inclusions- micro spheres. The paper suggests that distribution of micro spheres in SF should be used as a qualitative measure for estimation procedures. Comparison of such distribution for various models can be used for explaining the SF efficiency estimations. Materials and methods. The initial data inputs for the study were the composition and structure of syntactic foam and characteristics of its components: polymer matrix and glass micro spheres. Numerical studies were carried out using the earlier developed structural model of SF deformation and damage. The structural model assesses the stressed-strained state of large micro sphere assemblies (models with a number of spheres about 105 are used in the study). Results obtained by the model let us use statistical methods of processing the stress raisers and identify patterns of distributions for predicting the SF strength. The results are verified by comparison with estimations by finite element models. Main results. The structural model of deformation and damage is highly effective in calculation of the stressed-strained state of micro structures with a number of micro spheres of about 105 and more. Conclusion. The structural model developed for SF makes it possible to accurately assess the stresses of its components under external hydrostatic pressure considering a large number of micro spheres. The results show excellent convergence of the stressed-strained state estimates with detailed estimations by FE models. With accurate data on the stressed-strained state of micro structure one can predict how the damage would develop and calculate the process to failure and full loss of buoyance.

Preparation and Characterization of a Thermal Barrier Heat-Resistant Silicone Coating

In this study, a heat resistant coating with thermal barrier property was designed. Two types of silicone resin (based on methoxy methyl polysiloxane and methyl phenyl silicone resin) were used as thermal resistant binders, and the black iron oxide pigment and glass micro hollow sphere (MHS) additive were utilized to formulate the heat resistant/thermal barrier coatings. Coatings were applied to the steel substrates, and general properties of the coatings such as film formation, curing, and adhesion were then studied. The thermal stability of the coatings was evaluated by thermogravimetric analysis up to 450 °C. The thermal conductivity coefficient of the coatings was measured by temperature modulated differential scanning colorimeter (TMDSC). Investigation of the properties of all coatings showed that the silicone coating with the 7% of hollow microsphere had higher thermal stability (Tmaximum weight loss= 538 °C) and better barrier properties (Thermal conductivity= 0.29 W/mK (compared with other coatings.

Study on Fe-Based Metallic Glass Micro Hole Machining by Using Micro-EDM Combined with Electrophoretic Deposition Polishing

Fe-based metallic glass possesses high hardness and brittleness. It is a hard-to-cut metal material and difficult to machine by conventional methods. Although electrical discharge machining (EDM) has advantages in machining hard-to-cut metal materials, recast layer, pores, and micro cracks will form on the machined surface after machining. The study used a helical tool for the micro electrical discharge drilling (µ-EDD) process on Fe-based metallic glass. The influence of processing parameters, including the pulse on time, gap voltage, duty factor, and spindle rotational speed on the micro hole machining quality characteristics was investigated. The helical tool with SiC electrophoretic deposited (EPD) film was used to polish the inner surface of the electrical discharged micro hole. The findings show that the best micro hole accuracy, tool wear length, and inner surface were obtained at the spindle rotation speed of 1150 rpm, pulse on time of 5 μs, gap voltage of 30 V, and duty factor of 40%. The inner surface roughness can be reduced to 0.018 µm by using EPD tool. The inner surface was polished up to form a mirror surface.

724. LDBIO Toxoplasma Test in the United States and Beyond: Review of the Device’s Performance on U.S. Samples and its Ability to Avoid False Positives

BackgroundPart of an essential “toolbox” to eliminate Toxoplasma gondii infection is prompt recognition of acute infection acquired during gestation, in order to initiate treatment for congenital toxoplasmosis (CT). From conception to one month post-partum, screening seronegative pregnant women monthly for antibody to the parasite enables treatment that prevents trans-placental transmission of newly acquired maternal Toxoplasma, or that attenuates signs and symptoms of CT. Tests that are highly sensitive and specific—and that meet the other World Health Organization ASSURED criteria for diagnostics—are very useful for this kind of screening. Herein, we evaluated the accuracy of a test that meets these criteria—the LDBIO Toxoplasma ICT IgG-IgM device (LDBIO)—and whether it eliminated difficulties of other tests with false positive IgM results. World Health Organization A.S.S.U.R.E.D. criteria These are criteria for ideal screening or diagnostic tests, as described in a September 2017 paper in the Bulletin of the World Health Organization. Our study focused mostly on sensitivity and specificity for the LDBIO immunochromatography test for IgG and IgM specific to Toxoplasma gondii.MethodsBoth parts of this study examined results generated by the LDBIO device—a point-of-care immunochromatography test for Toxoplasma IgG and IgM—using serum and whole blood samples. With whole blood, thirty microliters were collected using a glass micro hematocrit tube. With both sera and whole blood, samples were loaded into the well of the LDBIO device, which took 20 minutes to generate results. In the first part of this study, we summarized results from three published U.S. studies and added new data from an ongoing clinical trial at the University of Chicago Medical Center (UCMC). In the second part of this study, we compiled data on how the LDBIO device performed on a total of 69 samples from U.S. and French studies that had led to false positive results when tested with commercially available comparator tests. Four of these false positives came from the UCMC trial.UCMC Feasiblity Study Flowchart Flowchart for ongoing feasibility study on the LDBIO device at the University of Chicago Medical Center. Data from this study may inform whether the LDBIO test—which already has the CE Mark for use in Europe—will receive 510(k) approval from the Food and Drug Administration in the U.S.Steps for Using LDBIO Device (A,B) Clean fingertip; prick with lancet (if collecting whole blood only) (C,D) Collect 30 uL in capillary tube (WB only) (E,F) Apply serum or blood sample to well; add four drops buffer and wait about 20 minutes (G) How to interpret results: black line under “T” corresponds to IgG and/or IgM to T. gondiiResultsLDBIO had only one false negative for a total of 664 samples from three earlier U.S. studies and the UCMC feasibility study. Meanwhile, out of 69 total false positives from various non-reference laboratory comparator tests, such as the Bio-Rad Platelia and Siemens kits, the LDBIO generated zero false positives.LDBIO's Performance on U.S. Samples Since 2014 In all four U.S. studies (total 664 patients), the LDBIO device generated one false negative result and zero false positive results.LDBIO vs. Comparator Tests Since 2017 In these three clinical settings (69 total samples), LDBIO correctly avoided generating the same false positive that had been generated by a test already cleared for widespread use in the U.S. or France.ConclusionAs LDBIO shows high sensitivity and specificity and can avoid confounding false positive results, this device merits consideration as a high-quality screening test that can assist public health efforts to improve CT care worldwide.Countries Working to Implement Regular Prenatal Screening for CT Prevention The countries in green represent countries currently working with the University of Chicago to implement regular prenatal screening programs for Toxoplasma gondii: U.S., Panama, Colombia, Brazil, Morocco, and France. Screening programs in all six countries rely on low-cost, highly-accurate screening technology that meets the WHO's ASSURED criteria. The LDBIO test -- which is already in use in France -- may become a usable resource in the other five countries if it gains FDA approval.Disclosures All Authors: No reported disclosures

Influence of La-impurities and plasma treatment on the structural and optical properties of some bismuth calcium borate glasses

This research work aims to the estimation of the effect of the addition of La2O3, by different amounts in wt. %, to the matrix of the bismuth calcium borate glass. The fast cooling procedure was used to prepare the suggested compositions. XRD was used to inspecting the internal structural phases of the prepared samples, where XRD patterns confirmed the amorphous natures of all samples. It was found that the La-additives act to increase the glass density, micro hardness, and optical absorption. While the plasma treatment using N2 acted to reduce both the relative intensity of XRD and the optical absorption.

Nano-Hydroxyapatite Scaffold Based on Recombinant Human Bone Morphogenetic Protein 2 and Its Application in Bone Defect Repair.

The best way in which to prepare scaffolds with good biological properties is an urgent problem in the field of tissue engineering. In this paper we discuss the preparation of nano-hydroxyapatite scaffold of recombinant human bone morphogenetic protein-2 (rhBMP-2) and its application in bone defect repair. rhBMP-2 reagent was dissolved in 1 mol/L sodium dihydrogen phosphate solution, and the rhBMP-2 solution was added to the nano-hydroxyapatite artificial bone with a 100 μL glass micro dropper at the rate of 10 drops/min to obtain Nano-HA/rhBMP-2 composite artificial bone. In in vivo experiments, rabbits were fixed on an operating table, a 2 cm longitudinal incision was made in the middle part of the radial forearm, and the radius was cut with a wire saw and periosteum, 2.5 cm away from the distal radius. After washing the wound with normal saline, Adv-hBMP-2/MC3T3-E1 nano-HA composite artificial bone, MC3T3-E1 nan-HA composite artificial bone, or Nano-HA artificial bone were implanted in different groups. The artificial bone scaffold prepared in this study has a stronger ability to repair bone defects than the alternatives, and is a promising prospect for the clinical treatment of bone defects.

Research Progress of Slag Structure and Hydration Activity

Slag is widely used as mineral admixtures in cement-based materials by its potential hydration activity. It has the advantage of saving resources and energy, reducing carbon emission, improving the performance of concrete, and plays an increasingly important role in the building materials industry. But the early strength of slag is low, and the industrialization of useful hydration products also need to be activated, so the utilization rate of slag in high grade cement is restricted. The hydration activity of slag depends not only on the content of vitreous in slag, but also on the structure of vitreous slag. To explore slag glass micro composition and structure of its active role, The slag micro-structure was analyzed from the structure levels, and then the factors affecting the activity of slag was evaluated. The potential advantages and disadvantages of some different methods to active slag were discussed such as physical ways, chemical activation method and compound activation way. The existing problems and development direction of improving the activity of slag were summarized , which could provide a valuable reference for the efficient use of slag.