Stabilization loop of a two axes gimbal system using self-tuning PID type fuzzy controller

The application of inertial stabilization system is to stabilize the sensor's line of sight toward a target by isolating the sensor from the disturbances induced by the operating environment. The aim of this paper is to present two axes gimbal system. The gimbals torque relationships are derived using Lagrange equation considering the base angular motion and dynamic mass unbalance. The stabilization loops are constructed with cross coupling unit utilizing proposed fuzzy PID type controller. The overall control system is simulated and validated using MATLAB. Then, the performance of proposed controller is evaluated comparing with conventional PI controller in terms of transient response analysis and quantitative study of error analysis. The simulation results obtained in different conditions prove the efficiency of the proposed fuzzy controller which offers a better response than the classical one, and improves further the transient and steady-state performance.     

Synthesis,Characterization and Evaluation of the Surface Active Properties of Novel Cationic Imidazolium Gemini Surfactants

New imidazolium gemini surfactants were synthesized by reaction of epichlorohydrin with long chain fatty alcohols furnishing products 2-(alkoxymethyl)oxirane followed by their subsequent treatment with imidazole resulting in the formation of 1-(1H-imidazol-1-yl-3 alkoxy)propane-2-ol which on subsequent treatment with 1,2-dibromoethane and 1,3-dibromopropane resulted in the formation of title gemini surfactants:1,2-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)ethane bromide (7), 1,3-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)propane bromide (8), 1,2-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)ethane bromide (9), 1,3-bis(1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)propane bromide (10), 1,2-bis (1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)ethane bromide (11) and 1,3-bis (1(3-alkoxy-2-hydroxypropyl)-1H-imidazol-3-ium)propane bromide (12). Their identification was based on IR, ¹H-, ¹³C-NMR, DEPT, COSY and mass spectral studies. Their surface active properties were also evaluated on the basis of surface tension and conductivity measurements.     

Vapor-liquid equilibrium of ethanol/ethyl acetate mixture in ultrasonic intensified environment

A vapor-liquid equilibrium (VLE) study was conducted on ethanol/ethylacetate mixture as a preliminary step towards developing an ultrasonic-assisted distillation process for separating azeotropic mixtures. The influence of ultrasonic intensity and frequency on the vapor-liquid equilibrium (VLE) of the mixture was examined using a combination of four ultrasonic intensities in range of 100–400W/cm² and three frequencies ranging from 25–68 kHz. The sonication was found to have significant impacts on the VLE of the system as it alters both the relative volatility and azeotrope point, with preference to lower frequency operation. A maximum relative volatility of 2.32 was obtained at an intensity of 300 W/cm2 and a frequency of 25 kHz coupled with complete elimination of ethanol-ethyl acetate azeotrope. Results from this work were also congruent with some experimental and theoretical works presented in the literature. These findings set a good beginning towards the development of an ultrasonic assisted distillation that is currently in progress.     

Investigating Factors Affecting Water-In-Diesel Fuel Nanoemulsions

In this work, water-in-diesel fuel nanoemulsions were prepared with mixed nonionic surfactants. Several mixtures of sorbitan monooleate and polyoxyethylene (20) sorbitan monooleate, with different Hydrophilic–Lipophilic Balance (HLB) values (9.6, 9.8, 10, 10.2 and 10.4) were prepared to achieve the optimal HLB value. Three mixed surfactant concentrations were prepared at 6, 8 and 10 wt% to identify the optimum concentration. Five emulsions with different water contents: 5, 6, 7, 8 and 9 % (wt/wt) were prepared using a high energy method under the optimum conditions (HLB = 10 and mixed surfactant concentration = 10 %). The effect of the HLB value, mixed surfactant concentration and water content on the droplet size has been studied. The interfacial tension and thermodynamic properties of the individual and the blended emulsifiers were investigated. Droplet size of the prepared nanoemulsions was determined by dynamic light scattering and the nanoemulsion stability was assessed by measuring the variation of the droplet size as a function of time. From the results obtained, it was found that the mean droplet size was formed between 49.5 and 190 nm depending on the HLB value, surfactant concentration and water content of the blended emulsifiers.     

Taxonomic investigation of selected rust fungi using scanning electron microscopy from Khyber Pakhtunkhwa,Pakistan

Rusts comprises the largest natural group of plant pathogens including approximately 8% of all described Fungi. Rust fungi are extremely plant pathogens responsible for great losses to agriculture productivity. Rust species belong to several genera among which more than half are Puccinia species. In Pakistan, rust causes severe damage to agriculture crops. Current study was carried out to identify and characterize different rust species common in the research area through microscopy and Scanning electron microscopy (SEM) in Khyber Pakhtunkhwa, Pakistan. Morpho-anatomical investigation of each collected rust species was carried out using different standard protocols. The dimensions of spores were measured and snapped under a stereomicroscope. SEM was used to examine the shape, size, and ornamentation of the spores of each rust fungus. Results revealed documentation of seven rust fungi, that is, Melampsora euphorbiae, Phragmidium barclayi, Puccinia nepalensis, P. exhausta, P. menthae, Uromyces capitatus, and Uromyces decorates belong to four different genera, were recorded. SEM revealed that spermogonia and Aecia were missing in most of the rust fungus studied. Uredinia was found in a scattered, irregular, lengthy, and epidermis-enclosed form. Urediniospores were found to be ovulating, elongated, echinulate, globose to sub-globose, ellipsoid to ovoid, and globose to sub-globose. Telia was found as sub-epidermal, amphigenous, dispersed, minute, and spherical cells. Teliospores ranged in form from cylindrical to oblong. The germ pores were detected in both apical (top cell) and basal (bottom cell) idiosyncratic and pedicel-attached cells. The techniques used in the current investigation will aid mycologists in rust identification and microscopic characterization.     

Palyno-anatomical characters and their systematic significance in the family Apiaceae from Chitral,eastern Hindu Kush,Pakistan

The present study was performed to provide a detailed explanation of leaf epidermal anatomy and pollen micromorphological features of selected species of family Apiaceae from Chitral, eastern Hindu Kush region as the basis of forthcoming studies. In the present article pollen morphology of eight species and foliar epidermal of seven species of family Apiaceae have been examined through microscopic techniques. In results two types of pollen prolate (five species) and perprolate (three species) with three colpi have been recorded. The exine ornamentation was found to be regulate, striate, and cerebroid. Largest pollen was found in Heracleum leucocarpum with the polar diameter of 43.25 μm and equatorial diameter of 21.6 μm. Smallest pollen was observed in Elaeosticta chitralica with the polar diameter of 18.4 μm. The P/E ratio varied from 1.59 to 2.16. Regarding to foliar epidermal anatomy, three types of epidermal cells including rectangular, irregular, and polygonal with variation in anticlinal wall pattern were determined. In the selected species three kinds of stomata comprising anisocytic, anomocytic, and paracytic type were reported in the current research. The size of epidermal cells ranged from 106 × 42.50 μm in Bupleurum falcatum subsp. cernuum and 77.25 × 26.35 μm in Prangos pabularia in adaxial surface. Largest stomatal complex was found in Prangos pabularia both in adaxial 33.55 × 20.05 μm and abaxial 50.25 × 39.40 μm. All the observed quantitative and qualitative features of the species were proved to be useful in the delimitation of species at generic and species level.     

Pollen morphology and its taxonomic potential in some selected taxa of Caesalpiniaceae observed under light microscopy and scanning electron microscopy

Pollen micromorphology is not only used to check the functional and structural evolution in plants but also to solve the taxonomic problem related to the classification of plants. Therefore, keeping in view the significance of pollen traits, selected taxa of the subfamily Caesalpiniaceae was collected from different geographical regions of Pakistan. The species were then analyzed under both light microscopy and scanning electron microscopy techniques to investigate the importance of micromorphological characters of pollen in the identification and classification of species. Great variation was recorded in equatorial shape, surface ornamentation, tectum, polar diameter, equatorial diameter, and exine thickness. However, little variation was observed in pollen type, polar shape, and fertility of pollen. The equatorial shape of five types was observed: prolate, prolate-spheroidal, spheroidal-subprolate, subspheroidal-prolate, and subspheroidal. Four types of surface ornamentation, psilate, granulate, clavate, and perforate, were recorded. Tectum of five types, intactate, reticulate regulate, medium reticulate, tactate, and striate, was observed. Sexine was thicker than nexine in all studied species. The largest polar diameter was observed in Caesalpinia pulcherrima 64.1 μm while the smallest in Parkinsonia aculeata 26.1 μm. The largest equatorial diameter was found in C. pulcherrima of 70.25 μm whereas the smallest in P. aculeata 27.57 μm. All the pollens analyzed were tricolporate. All studied species have a fertility ratio of more than 90%. A taxonomic key was developed to show the variation in pollen features and delimit species for the correct identification. In conclusion, the pollen traits were found useful to define species boundaries at various taxonomic ranks and will strengthen the taxonomy of this subfamily. Besides, this study also explored the palynological traits and their implication in the taxonomy of the subfamily Caesalpiniaceae.     

Scanning electron and light microscopy of foliar epidermal characters: A tool for plant taxonomists in the identification of grasses

SEM and light microscopy are of special interest for biologist to observe various features of the living bodies. In the current study we observed the foliar epidermal micro‐morphological characters of 44 grass species using SEM and Light microscopy to assess their taxonomic utility for taxonomists in the identification process. The aim of this study is to use the foliar epidermal structural variations in both upper and lower surfaces for identification of grasses. Significant diversity was observed in both qualitative and quantitative characters using SEM and Light microscopy. Variations were observed in stomatal number, size, guard cells shape, silica bodies, macro‐hairs, micro‐hairs, epidermal cell number, subsidiary cells, prickles, hooks, papillae, and short and long cells. A taxonomic key is prepared using these variations for the identification of grass species. Based on these findings, SEM and Light microscopy of foliar epidermal features can be of special interest for taxonomists in the identification of complex grass taxa.