PDMS Bonding Technologies for Microfluidic Applications: A Review

This review summarizes and compares the available surface treatment and bonding techniques (e.g., corona triggered surface activation, oxygen plasma surface activation, chemical gluing, and mixed techniques) and quality/bond-strength testing methods (e.g., pulling test, shear test, peel test, leakage test) for bonding PDMS (polydimethylsiloxane) with other materials, such as PDMS, glass, silicon, PET (polyethylene terephthalate), PI (polyimide), PMMA (poly(methyl methacrylate)), PVC (polyvinyl chloride), PC (polycarbonate), COC (cyclic olefin copolymer), PS (polystyrene) and PEN (polyethylene naphthalate). The optimized process parameters for the best achievable bond strengths are collected for each substrate, and the advantages and disadvantages of each method are discussed in detail.

Formulation and Evaluation of Benzoyl Peroxide Injection

Objective: The present research has been undertaken for the formulation and evaluation of Benzoyl Peroxide Injection. It is used for Antiacne activity. Methods: Benzoyl peroxide is used as Antiacne. Methyl paraben, Propyl paraben and benzalkoniumchloride were used as preservatives. Water for injection is used as a vehicle. The following parameters were evaluated such as clarity test, leakage test, chearity test, assay and Sterility test. Results: The clearity test shows clear solution. Drug chearity test shows no chear in the vials. Leakage test shows no leakage in the vials. pH and drug content show the F1 batch was better the other batches. IR confirmed that all functional groups are same as benzoyl Peroxide. Conclusion: It was concluded that F1 batch is the good than the other batches. So F1 batch is good for the Parenteral use.

Repeated endotracheal tube cuff tears during nasotracheal intubation due to nasal cavity orthodontic micro-implant - A case report -

Background: Nasotracheal intubation is generally performed for intraoral surgery.Case: A 34-year-old female patient who underwent orthognathic surgery exhibited repeated endotracheal tube cuff tears during nasotracheal intubation. After intubation, leaks developed, and torn endotracheal cuff was observed in the removed endotracheal tube. Subsequently, re-intubation through the same nasal cavity was performed immediately, but leakage from the torn endotracheal tube cuff was re-observed. A leakage test of the extubated tube revealed air bubbles and leaks near the tube cuff due to the tear. Nasotracheal intubation was performed through the other nasal cavity, and there were no leakage findings or abnormalities. During the course of the surgery, the surgeon noticed that the orthodontic micro-implant deposited in the mid-tube cavity was exposed to the nasal cavity. Conclusions: We aimed to emphasize caution and discuss the possibility that orthodontic micro-implants that are not confirmed during preoperative evaluation may cause repeated endotracheal tube cuff tears.

Experimental Investigation of Leakage in the Modified Revolving Vane Expander

This study focuses on the leakage characteristics of a modified revolving vane expander (M-RVE) using both static and dynamic leakage analysis. The no-expansion scenario showed a maximum volumetric efficiency of 18.7% was achieved at 5.5 bar(g) suction pressure, showing the severity of internal leakages. The blocker angle study demonstrated the importance of the correct opening-angle selection to avoid under or over-expansion. The maximum volumetric efficiencies for opening angles of 94 deg and 145 deg were 2.8% and 8.3%, respectively, at suction and discharge pressures of 6.5 bar(g) and 1 atm, respectively. The static leakage test demonstrated that the M-RVE housing was properly sealed, and the observed leakage in the dynamic test was mostly due to internal leakages. The results showed that the leakages through the radial clearance, endface, and vane side gaps make up 54%, 33%, and 8.5% of the overall leakage. Comparison between the theoretical and experimental data of the leakages through the radial clearance gap showed significant deviations at higher suction pressures. The reasons are thought to be due to the shafts' tilt, and the cylinder and rotor head deflections. It is believed that the deflection of the shaft created new leakage paths or changed the geometry of the current paths.

Comparison of the Aerosol Photometer and Light Scattering Airborne Particle Counter (LSAPC) Methods for Installed Filter System Leak Testing

The installed filter system leak test method for cleanrooms and clean zones is described in ISO 14644-3, Cleanrooms and associated controlled environments—Part 3: Test method. Portions of the methods in ISO 14644-3 were adapted from IEST-RP-CC034.4[Schaumburg, Illinois, US: Institute of Environmental Science and Technology], which provides a set of recommended procedures for leak testing HEPA and ULPA filters in situ (in the field) with the aerosol photometer test method and the light scattering airborne particle counter (LSAPC) test method. Leak testing is performed to confirm that the final high efficiency air filter system is properly installed by verifying the absence of bypass leakage in the installation, and that the filters are free of defects (small holes and other damage in the filter medium, frame, seal and leaks in the filter bank framework). This study was conducted to compare the aerosol photometer and LSAPC methods. Testing in the study consisted of creating artificial leaks in the filter system, measuring the upstream and downstream concentrations with the aerosol photometer and with the LSAPC, and comparing the filter leak penetration results. Comparison testing was applied to the procedure for the installed terminal panel filter system leakage scan test (stationary measurement) and the procedure for evaluating overall leakage of high-airflow box-type filters mounted in a duct or air-handling unit (AHU) (overall leakage test). It was found that the aerosol photometer and the LSAPC gave similar results for filter leakage within experimental error. The comparison of the leakage scan tests (stationary measurement) showed that the penetration calculated for the channel ≥ 0.3 μm of the LSAPC with an air flow rate of 1cu ft/min (CFM) (28.3 l/min) was very similar to the penetration measured with the aerosol photometer for a leakage level >0.01 % of the upstream concentration. The comparison result of the overall leakage test showed that overall total penetration values, obtained after dilution of artificial calibrated leaks in the filter media, were identical, within the measurement uncertainty, for particles ≥0.3 μm whether the sampling rate of the LSAPC was 1 CFM (28.3 l/min) or 50 l/min. Several recommendations are provided. In particular, for filters mounted in a duct or AHU where the filter function is critical, the recommended method is the leakage scan test method, using a grid sampling method in a plane downstream of the filter (as agreed between customer and supplier).