Femtosecond laser microfabrication for opto-microfluidic devices in glass

The femtosecond laser has been a powerful tool to achieve laser processing and microfabrication due to the advantages of unprecedented high peak intensity, a small heat-affected zone and the capability of three dimensional fabrication on micro-/nano-scales. -- In recent years, opto-microfluidics has emerged and progressed rapidly with many practical applications. Various microchannels and optical components have been integrated into a palm-size chip to accomplish optical measurements, clinical diagnostics, molecular analysis, and chemical synthesis. Opto-microfluidic devices significantly reduce reagent consumption, waste production, analysis time and labour costs. -- In this dissertation, femtosecond laser microfabrication for the opto-microfluidic devices in fused silica is studied. Femtosecond laser microfabrication on the surface and in the bulk of the samples is achieved using analysis on the influence of various fabrication parameters. Fabrication of surface / bulk microchannels of variable specifications has been demonstrated by femtosecond laser microfabrication assisted by hydrofluoric acid etching. The feasibility of fabricating of waveguides in glass with femtosecond lasers has also been proved. Laminar flow and particle counting are accomplished with the femtosecond laser microfabricated opto-microfluidic devices. The effectiveness of these prototype opto-microfluidic devices is investigated

Opto-microfluidic devices with femtosecond laser microfabrication

Opto-microfluidics is a novel technology that integrates optical devices and systems with microchannels to investigate the properties of fluids. Opto-microfluidic devices have been increasingly recognized as important miniaturized devices for optical measurements, biological analyses, and chemical syntheses. These devices significantly reduce reagent consumption, waste production, analysis time and labour costs. Common fabrication techniques include soft lithography, microelectromechanical systems (MEMS) and hot embossing. In this dissertation, opto-microfluidic devices fabricated by two-photon polymerization (TPP) technique with femtosecond lasers and standard soft lithography are proposed. After analyzing the fabrication properties of the femtosecond laser, we choose optimal parameters to fabricate optical structures in photoresist material SU-8, and integrate them with microchannels which are produced by a standard soft lithographic technique. Diffractive grating, Mach-Zehnder interferometer (MZI) and optical microring resonators based refractive index (RI) and temperature sensors are designed, fabricated and demonstrated. The sensitivities in different conditions are thoroughly investigated. By combining fluid mechanics and optics, two functional opto-microfluidic devices realizing simultaneous particle sorting and RI sensing are successfully proved. In these devices, filters fabricated by femtosecond lasers are used to sieve and control the flow of particles in suspension, and then the purified liquid is induced into the optical structures to measure the RI. The opto-microfluidic devices described in this dissertation verify the practicability and effectiveness as a lab-on-a-chip platform

Femtosecond laser fabricated polymeric grating for spectral tuning

By taking advantages of the two-photon polymerization induced by femtosecond laser and the versatility of the femtosecond laser microfabrication, we demonstrate a femtosecond laser microfabricated polymeric grating for spectral tuning, in which gratings of different thicknesses achieve gradual tuning of a white incident light into output lights of different colors ranging from cyan to red, which is in good agreement with the simulation. Through the selection of different grating parameters, the technique developed in this study offers the possibility to tailor the performance of the grating to achieve specific grating efficiency or complete extinction at specific wavelengths, which is promising for measurements and applications in spectroscopy, sensing, integrated optical systems, and biomedicine

Construction of three-dimensional, homogeneous regenerative cartilage tissue based on the ECG-DBM complex

Introduction: The feasibility of using a steel decalcified bone matrix (DBM)-reinforced concrete engineered cartilage gel (ECG) model concept for in vivo cartilage regeneration has been demonstrated in preliminary experiments. However, the regenerated cartilage tissue contained an immature part in the center. The present study aimed to achieve more homogeneous regenerated cartilage based on the same model concept.Methods: For this, we optimized the culture conditions for the engineered cartilage gel-decalcified bone matrix (ECG-DBM) complex based on the previous model and systematically compared the in vitro chondrogenic abilities of ECG in the cartilage slice and ECG-DBM complex states. We then compared the in vivo cartilage regeneration effects of the ECG-DBM complex with those of an equivalent volume of ECG and an equivalent ECG content.Results and discussion: Significant increases in the DNA content and cartilage-specific matrix content were observed for the ECG-DBM complex compared with the ECG cartilage slice, suggesting that the DBM scaffold significantly improved the quality of ECG-derived cartilage regeneration in vitro. In the in vivo experiments, high-quality cartilage tissue was regenerated in all groups at 8 weeks, and the regenerated cartilage exhibited typical cartilage lacunae and cartilage-specific extracellular matrix deposition. Quantitative analysis revealed a higher chondrogenic efficiency in the ECG-DBM group. Specifically, the ECG-DBM complex achieved more homogeneous and stable regenerated cartilage than an equivalent volume of ECG and more mature regenerated cartilage than an equivalent ECG content. Compared with ECG overall, ECG-DBM had a more controllable shape, good morphology retention, moderate mechanical strength, and high cartilage regeneration efficiency. Further evaluation of the ECG-DBM complex after in vitro culture for 7 and 14 days confirmed that an extended in vitro preculture facilitated more homogeneous cartilage regeneration

Persepsi Masyarakat terhadap Alun-alun Kota Bandung sebagai Ruang Terbuka Publik

Bandung merupakan sebuah kota yang strategis yang memiliki nilai sejarah yang cukup panjang dalam masa perjuangan. Alun alun Bandung merupakan hasil warisan ciri kota tradisional yang dibangun oleh penguasa kolonial yang merupakan pusat ruang terbuka kota. Dari masa kemasa Alun-alun kota Bandung telah mengalami beberapa kali Perubahan, baik bentuk maupun fungsinya sehingga mengakibatkan degradasi makna terhadap fungsinya bagi masyarakat Kota Bandung itu sendiri. Maka fenomena tersebut mengarahkan kepada pertanyaan penelitian yaitu bagaimana persepsi masyarakat terhadap Alun-alun Kota Bandung ditinjau sebagai ruang terbuka publik. Tujuan penelitian ini adalah untuk mengetahui persepsi masyarakat terhadap Alun-alun Kota Bandung. Dari tujuan tersebut maka sasaran yang dilakukan adalah mengidentifikasi karakter dan fungsi ruang terbuka publik yaitu fungsi ekologis, arsitektural, dan sosial. Dari hasil analisis dengan menggunakan kuesioner yaitu uji sampel dengan regresi linear sederhana dengan pendekatan analisis pengguna dan analisis karakteristik ruang terbuka publik. Hasil penelitian ini menghasilkan penilaian baik terhadap korelasi variabel bebas yaitu persepsi masyarakat terhadap variabel terikat yaitu Alun-alun Kota Bandung, setiap kali pertanyaan yang berkenaan dengan Persepsi masyarakat terhadap Alun-alun Kota Bandung akan mempengaruhi nilai hasil pengujian yang cenderung meningkat akan keberadaan Alun-alun itu sendiri. Hasil penelitian ini bisa dimanfaatkan untuk mengangkat kembali citra Alun-alun Kota Bandung sebagai ruang publik atau (Central Square).[Public Perception of The Alun-alun Bandung as Public Open Space] Bandung is a city that has a value that strategic long history in the struggle. Alun Bandung square is the result of inherited traits of traditional town built by the colonial rulers which is the center of the city open space. Over time, Bandung town square has undergone several changes, both form and function, resulting in degradation of the meaning of the function for the city of London itself. The phenomenon then leads to the research question is how the public perception of the square is the city of Bandung reviewed as public open space for the present study tries to analyze the function of the existence of Bandung City Square as a public space. The purpose of this study was to determine the public perception of the square is the city of Bandung. From these objectives, the target does is identify the character and function of public open space that is the function of ecological, architectural and social. From the analysis by using a questionnaire that test samples with a simple linear regression analysis approach and analysis of the characteristics of users of public open space. The results of this study resulted in better assessment of the correlation of the independent variable is the public perception of the dependent variable is the town square of Bandung, every time queries regarding the public\u27s perception of the town square Bandung will affect the value of the test results are likely to increase in the existence Square itself. the results of this study can be used to lift the image of Bandung city square as a public space or (Central Square)

Test of Perfomance ERK Hybrid Dryer with Biomass Furnace as Additional Heating System for Nutmeg Seed (Myristica SP.) Drying

Conventional drying depend on the weather. It was caused agricultural product damaged, and moldy attack. So we need hybrid dryer with a source of radiation and solar biomass to continuous drying and can be controlled.The aims of this research is test performance of ERK hybrid dryer to drying the nutmeg seed during the drying process. Experiments were conducted to determine the distribution of temperature in the dryer in condition with no material and material conditions. Input of energy derived from biomass combustion in the furnace (evening) and combination of biomass and radiation (during the day). Measurements of temperature and RH using a thermocouple CC and alcohol thermometer. Temperature and RH to be measured include temperature and RH in dryer with several measurement points representing the up, middle , bottom and inlet temperature, outlet temperature and ambient temperature measurements at intervals of 30 minutes. The results showed average temperature ranges between 42 ° C - 51 ° C and RH ranged between 50.96 % -55.65 % . Time of drying is used to dry nutmeg from the initial moisture content from 80.72 % wb to 9.67 % wb is 52 hours with an average drying rate is 7.8 % db / hour . The total energy used to heat and vaporize materials,water that is 290 499.9 kJ. Efficiency of drying system 8.63% and energy of drying required to water evaporated is 28520.62 kJ / kg. The result quality of product obtained color of nutmeg generally more uniform

Microfabrication and Applications of Opto-Microfluidic Sensors

A review of research activities on opto-microfluidic sensors carried out by the research groups in Canada is presented. After a brief introduction of this exciting research field, detailed discussion is focused on different techniques for the fabrication of opto-microfluidic sensors, and various applications of these devices for bioanalysis, chemical detection, and optical measurement. Our current research on femtosecond laser microfabrication of optofluidic devices is introduced and some experimental results are elaborated. The research on opto-microfluidics provides highly sensitive opto-microfluidic sensors for practical applications with significant advantages of portability, efficiency, sensitivity, versatility, and low cost

Microfabrication and Applications of Opto-Microfluidic Sensors

A review of research activities on opto-microfluidic sensors carried out by the research groups in Canada is presented. After a brief introduction of this exciting research field, detailed discussion is focused on different techniques for the fabrication of opto-microfluidic sensors, and various applications of these devices for bioanalysis, chemical detection, and optical measurement. Our current research on femtosecond laser microfabrication of optofluidic devices is introduced and some experimental results are elaborated. The research on opto-microfluidics provides highly sensitive opto-microfluidic sensors for practical applications with significant advantages of portability, efficiency, sensitivity, versatility, and low cost