Search

Evaporative coolers with single-phase induction motors (SPIMs) are one of the least efficient and most commonly used electrical power consumers all over the world. Recently, it has been suggested to substitute SPIMs with higher efficiency motors, such as permanent magnet brushless (PMBL) motors. However, control method for brushless motors often works based on speed, while laboratory tests indicate that due to fluid characteristics of the blower, the airflow rate is not just related to the speed, where increasing the cooler’s duct length reduces the airflow rate, thereby preventing the desired airflow rate to be reached. To overcome this problem, in this paper, a new power-based control scheme has been developed to stabilize the outlet airflow rate instead of the speed control. In this approach, the output power of PMBL motor is regulated around a set point power corresponding to the desired airflow rate. A 5000-m3/h evaporative cooler equipped with the brushless motor was tested with both constant speed and power control strategies. Results indicated the superiority of the proposed brushless motor drive and power control scheme.

Mesenchymal stem cells (MSCs) are multipotent stromal cells that can differentiate into a variety of cell types. They control the process of hematopoiesis by secreting regulatory cytokines and growth factors and by the expression of important cell adhesion molecules for cell-to-cell interactions. This investigation was intended to examine the effect of bone marrow (BM)-derived MSCs on the differentiation of HL-60 cells according to morphological evaluation, flow cytometry analysis, and gene expression profile.The BM-MSCs were cultured in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum (FBS). After the third passage, the BM-MSCs were irradiated at 30 Gy. To compare how the HL-60 cells differentiated in groups treated differently, HL-60 cells were cultured in RPMI-1640 and supplemented with 10% FBS. The HL-60 cells were seeded into six-well culture plates and treated with all-trans-retinoic acid (ATRA), BM-MSCs, or BM-MSCs in combination with ATRA, while one well remained as untreated HL-60 cells. The expression levels of the granulocyte subset-specific genes in the HL-60 cells were assayed by real-time polymerase chain reaction.Our results revealed that BM-MSCs support the granulocytic differentiation of the human promyelocytic leukemia cell line HL-60.Based on the results of this study, we concluded that BM-MSCs may be an effective resource in reducing or even preventing ATRA's side effects and may promote differentiation for short medication periods. Though BM-MSCs are effective resources, more complementary studies are necessary to improve this differentiation mechanism in clinical cases.Amaç: Mezankimal kök hücreler (MKH) birçok hücre tipine göre farklılaşabilen multipotent stromal hücrelerdir. Hematopoez sürecini düzenleyici sitokinler ve büyüme faktörleri salınımı ile ve hücreler arası etkileşim için önemli hücresel adezyon moleküllerinin ifadesi yoluyla kontrol ederler. Bu çalışma da kemik iliği (Kİ) kaynaklı MKH HL-60 hücrelerinin farklılaşması üzerine etkisini morfolojik değerlendirme, akım sitometri ve gen ifade analizi yöntemleriyle araştırılması amaçlanmıştır. Gereç ve Yöntemler: Kİ-MKH %10 fetal sığır serumu (FSS) içeren Dulbecco’nun modifiye Eagle ortamında kültür edildi. Üçüncü pasaj sonrası, Kİ-MKH 30 Gy ile ışınlandı. HL-60 hücrelerinin farklı şartlarda nasıl farklılaştığını karşılaştırmak için HL-60 hücreler %10 FSS eklenmiş RPMI-1640 ortamında kültür edildi. HL-60 hücreleri altı kuyucuklu plaklarda all-trans retinoik asit (ATRA), Kİ-MKH ve ATRA ile birlikte Kİ-MKH ile muamele edilirken, bir kuyucuğa sadece HL-60 hücreleri kondu. HL-60 hücrelerinde granülosit alt gruplarına özgü genlerin ifade düzeyleri gerçek zamanlı polimeraz zincir reaksiyonu ile değerlendirildi. Bulgular: Sonuçlarımız Kİ-MKH’nin insan promiyelositik lösemi hücre dizisi HL-60’ın granülositik farklılaşmasını desteklediğini gösterdi. Sonuç: Bu çalışmanın bulgularına göre, Kİ-MKH’nin ATRA yan etkilerini azaltıcı ve hatta önleyici etkili bir kaynak olduğu ve kısa ilaç kullanımı süreçlerinde farklılaşmayı uyarabileceği sonucunu çıkarttık. Kİ-MKH etkili bir kaynak olsa da, klinik olgularda bu farklılaşma mekanizmasını iyileştirmek için destekleyici ek çalışmalara ihtiyaç vardır.

Evaporative coolers due to their low cost are used in hot and dry regions of many countries especially in Iran. Conventional evaporative coolers use single-phase induction motors (SPIMs). But the benefits of these motors are very low, and their substitution with high efficient electrical motors is considered by industrial parties. In this paper, the details of using the brushless motor in the application of evaporative cooler are presented. A 1/2 hp brushless motor and drive are designed and built. This motor- drive is tested by a dynamometer and standard testing equipment. Also, for the approval of this motor-drive, a 5000 m3/h direct evaporative water cooler equipped with this motor is examined under the airflow rate test in the reference laboratory. The results obtained in both tests are compared with the test results of a typical SPIM. The results verify an increase of at least 60% for energy efficiency compared to evaporative coolers equipped with SPIM. Moreover, a new control scheme based on power control instead of speed control is proposed to stabilize the outlet airflow rate. The results indicate that use of brushless motors in this application can offer considerable energy saving, and helps to protect environment.