Intensification of heat and mass transfer of the gas channel of the multi-temperature condensation filter

The principle of operation and features of hydrodynamics and heat-mass transfer in the working channel of a multi-temperature condensation filter for gas purification are described. Promising methods of gas flow purification using porous surfaces are described. The modeling and comparison of the laminar air flow in channels of various shapes: in a flat channel, in a channel with webs and in a spiral channel are performed. An analysis of their effectiveness is carried out.

Experimental Investigation of Performance Characteristics for Savonius-Style VAWTs: A Comparative Study

Savonius-style wind turbines are mainly gauged by two types of coefficients namely: (i) coefficient of power (CP) and (ii) coefficient of torques (CT). Coefficient of power is defined as the ratio of power generated by the turbine to the total power available to the turbine from the free-flowing wind. This is synonymous to the operational efficiency of the wind turbine. Coefficient of torque reflects the torque generating ability of the turbine. In this manuscript, experiments have been performed using three different types of rotor profiles for Savonius-style wind turbines (SSWTs) namely, classical SSWT, Benesh type SSWT and elliptical shaped SSWT using oriented jets. Using deflector plates the orientation of jets have been varied from 20° to 70°. Addition of deflector plates to the wind turbines, assists in maximizing the utilization of wind energy. Experiments have been performed in the laminar air flow. Mechanical loads have been used to study Coefficient of performance (CP) and coefficient of torque (CT) as a function of tip speed ratio (TSRs). The velocity of the wind is adjusted by varying the rheostat that controls the AC motor for the wind tunnel systems. Experimental results indicated that optimum performance could be achieved from all three types of SSWT variants at TSR ∼ 0.70. Out of the three designs studied in this manuscript, elliptic shaped SWT yielded best coefficient of performance equal to 0.39 at TSR = 0.70.

Visualization of Airborne Particles as a Risk for Microbial Contamination in Orthopedic Surgery

Background: The operating theater is recognized to involve a high frequency of occupational blood and body fluid contacts.Objectives: This study aimed to visualize the production of blood and body fluid airborne particles by surgical procedures and to investigate risks of microbial contamination of the conjunctival membranes of surgical staff during orthopedic operations.Methods: Two physicians simulated total knee arthroplasty (TKA) and total hip arthroplasty (THA) in a bio-clean theater using model bones. The generation and behaviors of airborne particles were filmed using a fine particle visualization system, and numbers of airborne particles per 2.83 L of air were counted at the height of the operating and instrument tables. Each action was repeated five times, and particle counts were evaluated statistically.Results: Numerous airborne particles were dispersed to higher and wider areas while “cutting bones in TKA” and “striking and driving the cup component on the pelvic bone in THA” compared to other surgical procedures. The highest particle counts were detected while “cutting bones in TKA” under unidirectional laminar air flow.Discussion: These results provide a clearer image of the dispersion and distribution of airborne particles and identified higher-risk surgical procedures for microbial contamination of the conjunctival membranes. Surgical staff including surgeons, nurses, anesthesiologists, and visitors, should pay attention to and take measures against occupational infection particularly in high-risk surgical situations.

Modifikasi Laminar sebagai Alat Pembelajaran Biologi SMA Materi Mikroorganisme

Pada umumnya, untuk memperoleh ruang kerja steril digunakan laminar air flow, namun karena harganya relatif mahal menjadikan tidak terbeli. Oleh karena itu, dilakukan inovasi untuk membuat laminar modifikasi (Lamodis). Tujuan pembuatan lamodis adalah dapat memberikan ruang kerja steril dengan harga lebih murah daripada laminar pada umumnya karena tingkat keberhasilan yang tinggi atas praktikum didukung oleh ruang kerja yang steril. Penulisan best practise ini bertujuan untuk mengatasi kegagalan praktikum Biologi pada materi yang terkait dengan mikroorganisme agar siswa mendapatkan pemahaman yang lebih baik akan materi dan meningkatkan keterampilan di setiap langkah dalam melakukan praktikum terkait mikrorganisme dengan menggunakan lamodis. Pembuatan Lamodis menggunakan bahan-bahan yang ada di sekitar namun tetap mengaplikasikan prinsip dasar pembuatan. Uji kontaminasi media yang dituang di dalam dan di luar Lamodis menunjukkan bahwa uji di dalam Lamodis memiliki persentase tidak terkontaminasi sebesar 83,5%, yang lebih baik daripada di luar Lamodis yang sebesar 79%. Hasil rerata nilai angket terhadap siswa adalah 3,31 dari maksimal 4,00 yang menunjukkan bahwa Lamodis cukup baik untuk digunakan untuk sterilisasi. Penggunaan Lamodis meningkatkan keterampilan siswa dalam melakukan prosedur aseptik. Karenanya pembuatan Lamodis mendukung pembelajaran Biologi SMA yang terkait dengan mikroorganisme.

Сверхзвуковое ламинарное обтекание затупленного ребра: двойственность численного решения

Results of numerical simulation of supersonic flow past a blunt fin mounted on a plate with a developing laminar boundary layer are presented. Generally, the case considered corresponds to the flow configuration used in the experimental and computational study by Tutty et al (2013), where the laminar air flow with the freestream Mach number of 6.7 is considered. The simulation was performed for different values of Reynolds number ranging from 5000·to 20000. Two stable solutions corresponding to metastable flow states with different configurations of the vortex structure were predicted within some range of Reynolds number. The bifurcation diagrams showing the main horseshoe vortex center location and the length of separation region versus the Reynolds number is presented, critical Reynolds number corresponding to occurrence of the second isolated solution is evaluated.