A novel two-polynomial criteria for higher-order systems stability boundaries detection and control

There are many methods for identifying the stability of complex dynamic systems. Routh and Hurwitz’s criterion is one of the earliest and commonly used analytical tools analysing the stability of dynamic systems. However, it requires tedious and lengthy derivations of all components of the Routh array to solve the stability problem. Therefore, it is not a simple method to define analytically, stability boundaries for the coefficients of the system characteristic equation.The proposed brand-new criterion is an effective alternaztive technique in identifying stabilityhigher-order linear time-invariant dynamic system that binds the coefficients of the system characteristic polynomial at the stability boundaries by means of an additional single constantk. It defines the necessary and sufficient conditions for the absolute stability of higher-order dynamic systems. It also allows the analysing of the system’s precise marginal stabilityor marginal instability condition when the roots are relocated on imaginary jω-axis of s-plane. The criterion proposed bythe authors, in contrast to Routh criteria, simplifies the identification of maximum and minimum stability limits for any coefficient of the higher-order characteristic equation significantly. The derived in the paperstability boundary formulas for the polynomial coefficients are successfully used for the proportional integral derivative (PID) controller with single or multiple gains selections in closed-loop control system

Investigation of the effective factors on rate of stemflow for tree species in Hyrcanian forests

The objective of this study was (i) to compare the amount of stemflow in deciduous broadleaved trees (with and without leaves) in accordance with different growth seasons and (ii) to compare the rate of stemflow in coniferous and broadleaved trees in according to the canopy cover area. Stemflow was measured on 20 marked trees using a stemflow collector. Rates were different for the different tree species Beech Fagus orientalis L, Ironwood Parrotia persica L., Alder Alnus subcordata L. and Hornbeam Carpinus betulus L., and were greater in autumn than winter even though trees were then in leaf. The stemflow increased with increasing canopy cover area. Even though canopy cover in conifers (Cupressus sempervirens var. horizontalis) was less than the broad-leaved beech, the rate of stemflow was higher, up to 7 litres per hour with relatively small canopies.Keywords: canopy, seasons, conifers, broad-leaved tree

Comparing the effect of using normal saline, N-acetyl cysteine and not using them in endotracheal tube suction on physiologic parameters and the amount of secretions in intubated patients under mechanical ventilation

Aims: Today a large number of patients hospitalized in Intensive Care Unit need mechanical ventilation via an artificial air way. Since these patients have endotracheal tube, endotracheal suctioning is necessary for increasing oxygenation, cleaning the airway and keeping it open. But this method consists of various side effects such as increased blood pressure and heart rate and respiratory rate, cyanosis, dizziness and increased intracranial pressure and hypoxia. This study aimed at comparing the effect of using normal saline serum, N-acetyl cysteine and not using them in endotracheal suctioning on physiologic parameters and the amount of secretions in intubated patients under mechanical ventilation. Material & Methods: It was a controlled clinical trial study with random allocation that was performed on 54 intubated patients hospitalized in ICU of health educational centers of Babol Medical Sciences University in 2014. Endotracheal tube suctioning was performed for each patient once without saline, the second time with 3 ml of normal saline and the third time with 2 ml of N-acetyl cysteine. Blood pressure, Heart rate, Respiratory rate, Arterial oxygen saturation were measured and recorded before each stage of suctioning and two and five minutes after that. Amount of secretions was measured after each method of suctioning. Data were analyzed by SPSS16 statistical software, variance analysis with repeated measures, ANOVA and paired t statistical tests. Results: Blood pressure, Heart rate and Respiratory rate were increased after suction in all the three groups, but these changes were higher in the group that received normal saline. Mean decrease of Arterial oxygen saturation was more in the method of receiving normal saline (p<0.05). The amount of secretion was more in the method of receiving N-acetyl cysteine (p=0.004). Conclusions: Endotracheal tube suctioning by using normal saline had more adverse effects on post- suction physiological parameters in compare with the other two methods. Therefore, it is recommended to not use normal saline in endotracheal tube suctioning to the possible extent, and if removing secretions is required, endotracheal N_acetyl cysteine should be used according to the patient's condition

Pengembangan Desain Fixture Display Pakaian Dan Fitting Room Untuk Penggunaan Pameran

Pameran merupakan salah satu alternatif bagi sebuah Perusahaan atau toko untuk memasarkan produknya.Salah satu jenis pameran adalah pameran pakaian.Pakaian tentunya membutuhkan sebuah fixture sebagai fasilitas display untuk dipasarkan, selain itu kebutuhan fitting room menjadi hal yang vital sebagai salah satu fasilitas konsumen memutuskan membeli. Dalam penelitian ini terlihat bahwa penggunaan fittingroom dalam pameran sangat minim, dan berbanding terbalik dengan kebutuhan konsumen sehingga dalam pelaksanaanpameran ketiadaan fittingroom menjadi salah satu penghambat konsumen dalam membeli pakaian. Ketiadaan fittingroom ini dikarenakan masih kurangnya fasilitas fittingroom yang mobile dan kebutuhan tenant memamerkansemua produknya. Setelah melakukan proses desain dibuatlah sebuah display yang mampu dibentuk menjadi fitting room. Namun selama proses tersebut masih banyak kekurangan terutama pada aspek struktur yang sebaiknya mudah dipasang dan produksi yang murah agar dapat dijangkau oleh pengusaha yang baru memulai bisnis

Ultraporous Electron-Depleted ZnO Nanoparticle Networks for Highly Sensitive Portable Visible-Blind UV Photodetectors

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. A hierarchical nano- and microstructured morphology for visible-blind UV photodetectors is developed, which provides record-high milliampere photocurrents, nanoampere dark currents, and excellent selectivity to ultralow UV light intensities. This is a significant step toward the integration of high-performance UV photodetectors in wearable devices