Investigation of molecular polarizabilities and derivatives in halomethanes

The research undertaken was to obtain absolute Raman intensities for the symmetric stretching vibrations of the methyl halides, CH3X with (X=F, CI, Br), by experiment and theory. The intensities were experimentally measured using the Ar+ ion gas laser as excitation source, a Spex 14018 double monochromator and a RCA C-31034 photomultiplier tube as detector. These intensities arise from changes in the derivative of the polarizability (8 a'), with respect to vibration along a normal coordinate (8qi). It was intended that these derivatives obtained with respect to normal coordinates would be converted to derivatives with respect to internal coordinates, for a quantitative comparison with theory. Theoretical numerical polarizability derivatives for the stretching vibrations are obtained using the following procedure. A vibration was simulated in the molecule by increasi.ng and decreasing the respective bond by the amount ±o.oosA for the C-H bonds and ±o.oIA for the C-X (X=F, CI, Br) bond. The derivative was obtained by taking the difference in the polarizability for the equilibrium geometry and the geometry when a particular bond is changed. This difference, when divided by the amount of change in each bond and the number of bonds present results in the derivative of the polarizability with respect to internal coordinate i.e., !1u/!1r. These derivatives were obtained by two methods: I} ab initio molecular orbital calculation and 2} theory of atoms in molecules (AIM) analysis. Due to errors in the experimental setup only a qualitative analysis of the results was undertaken relative to the theory. Theoretically it is predicted that the symmetric carbonhalogen stretch vibrations are more intense than the respective carbon-hydrogen stretch, but only for the methyl chloride and bromide. The carbon fluorine stretch is less intense than the carbon-hydrogen stretch, a fact which is attributed to the small size and high electronegativity of the fluorine atom. The experimental observations are seen to agree qualitatively with the theory results. It is hoped that when the experiment is repeated, a quantitative comparison can be made. The analysis by the theory of atoms in molecules, along with providing polarizabilities and polarizability derivatives, gives additional information outlined below. The theory provides a pictorial description of the main factors contributing to the molecular polarizability and polarizability derivative. These contributions are from the charge transfer and atomic dipole terms i.e., transfer of charge from one atom to another and the reorganization of atomic electronic charge distribution due to presence of an electric field. The linear relationship between polarizability and molecular volume was also observed

Lesion detection and Grading of Diabetic Retinopathy via Two-stages Deep Convolutional Neural Networks

We propose an automatic diabetic retinopathy (DR) analysis algorithm based on two-stages deep convolutional neural networks (DCNN). Compared to existing DCNN-based DR detection methods, the proposed algorithm have the following advantages: (1) Our method can point out the location and type of lesions in the fundus images, as well as giving the severity grades of DR. Moreover, since retina lesions and DR severity appear with different scales in fundus images, the integration of both local and global networks learn more complete and specific features for DR analysis. (2) By introducing imbalanced weighting map, more attentions will be given to lesion patches for DR grading, which significantly improve the performance of the proposed algorithm. In this study, we label 12,206 lesion patches and re-annotate the DR grades of 23,595 fundus images from Kaggle competition dataset. Under the guidance of clinical ophthalmologists, the experimental results show that our local lesion detection net achieve comparable performance with trained human observers, and the proposed imbalanced weighted scheme also be proved to significantly improve the capability of our DCNN-based DR grading algorithm

Effect of 3 Key Factors on Average End to End Delay and Jitter in MANET

A mobile ad-hoc network (MANET) is a self-configuring infrastructure-less network of mobile devices connected by wireless links where each node or mobile device is independent to move in any desired direction and thus the links keep moving from one node to another. In such a network, the mobile nodes are equipped with CSMA/CA (carrier sense multiple access with collision avoidance) transceivers and communicate with each other via radio. In MANETs, routing is considered one of the most difficult and challenging tasks. Because of this, most studies on MANETs have focused on comparing protocols under varying network conditions. But to the best of our knowledge no one has studied the effect of other factors on network performance indicators like throughput, jitter and so on, revealing how much influence a particular factor or group of factors has on each network performance indicator. Thus, in this study the effects of three key factors, i.e. routing protocol, packet size and DSSS rate, were evaluated on key network performance metrics, i.e. average delay and average jitter, as these parameters are crucial for network performance and directly affect the buffering requirements for all video devices and downstream networks

A robust control design approach for altitude control and trajectory tracking of a quadrotor

Introduction. Unmanned aerial vehicles as quadcopters, twin rotors, fixed-wing crafts, and helicopters are being used in many applications these days. Control approaches applied on the quadrotor after decoupling the model or separate altitude control and trajectory tracking have been reported in the literature. A robust linear H∞ controller has been designed for both altitude control and circular trajectory tracking at the desired altitude. Problem. The ability of the quadrotor system to hover at a certain height and track any desired trajectory makes their use in many industrial applications in both military and civil applications. Once a controller has been designed, it may not be able to maintain the desired performance in practical scenarios, i.e. in presence of wind gusts. Originality. This work presents the control strategy to ensure both altitude control and trajectory tracking using a single controller. Purpose. However, there is a need for a single controller that ensures both altitude control and trajectory tracking. Novelty. This paper presents a robust H∞ control for altitude control and trajectory tracking for a six degree of freedom of unmanned aerial vehicles quadrotor. Methodology. Multi input multi output robust H∞ controller has been proposed for the quadrotor for altitude control and tracking the desired reference. For the controller validation, a simulation environment is developed in which a 3D trajectory is tracked by the proposed control methodology. Results. Simulation results depict that the controller is efficient enough to achieve the desired objective at minimal control efforts. Practical value. To verify that the proposed approach is able to ensure stability, altitude control, and trajectory tracking under practical situations, the performance of the proposed control is tested in presence of wind gusts. The ability of the controller to cater to the disturbances within fractions of seconds and maintaining both transient and steady-state performance proves the effectiveness of the controller.Вступ. Безпілотні літальні апарати, такі як квадрокоптери, двороторні апарати, апарати з нерухомими крилами та гелікоптери сьогодні використовуються у багатьох сферах застосування. У літературі повідомляється про підходи до керування, застосовані на квадрокоптері після від’єднання моделі або окремого контролю висоти та відстеження траєкторії. Надійний лінійний регулятор H∞ був розроблений як для контролю висоти, так і для відстеження кругової траєкторії на потрібній висоті. Проблема. Здатність квадрокоптерної системи зависати на певній висоті та відстежувати будь-яку бажану траєкторію робить їх застосування можливим у багатьох сферах як у військових, так і в цивільних цілях. Розроблений контролер може не підтримувати бажані характеристики у реальних умовах, тобто за наявності поривів вітру. Оригінальність. У цій роботі представлена стратегія керування, яка забезпечує як контроль висоти, так і відстеження траєкторії за допомогою одного контролера. Мета. Однак існує потреба в єдиному контролері, який забезпечує як контроль висоти, так і відстеження траєкторії. Новизна. У цій статті представлено надійний регулятор H∞ для контролю висоти та відстеження траєкторії для шести ступенів свободи безпілотних літальних апаратів. Методологія. Для квадрокоптера запропоновано багатовхідний багатовихідний надійний контролер H∞ для контролю висоти та відстеження бажаного курсу. Для перевірки контролера розробляється середовище моделювання, в якому тривимірна траєкторія відстежується за запропонованою методологією керування. Результати. Результати моделювання показують, що контролер є досить ефективним для досягнення бажаної мети при мінімальних зусиллях контролю. Практична цінність. Щоб переконатися, що запропонований підхід здатний забезпечити стабільність, контроль висоти та відстеження траєкторії в реальних ситуаціях, параметри запропонованого контролю перевіряються за наявності поривів вітру. Здатність контролера усувати порушення протягом кількох секунд і підтримувати як перехідні, так і стабільні показники доводить ефективність контролера

FORMULATION AND DEVELOPMENT OF MICROSPHERES FOR THE TREATMENT OF FAMILIAL ADENOMATOUS POLYPOSIS

Objective: Familial adenomatous polyposis (FAP) also known as familial polyposis coli, is a hereditary disease characterized by progressive appearance of numerous polyps mainly in the large intestine. Polyps are initially benign but can easily become cancerous and as such it is a life threatening condition. Celecoxib, a cyclooxygenase-2 (COX-2) inhibitor is thought to induce cell death, and thus prevent or delay the growth of polyps. So in the present study celecoxib loaded microspheres were prepared using control release Hydroxy propyl methyl cellulose (HPMC K4M) and pH dependent polymer eudragit L 100-55 in different ratios (1:1 to 1:4) respectively. The main objective of the study is to identify the polymer concentration required to prevent the drug release in stomach region and promotes in intestinal region.Methods: Emulsification solvent evaporation method was selected for the preparation and all the optimized formulations were evaluated for drug-polymer interactions, percentage yield, micrometric properties, entrapment efficiency, particle size analysis, differential scanning calorimetry and in vitro dissolution study.Results: Drug and polymer interactions were evaluated by using FTIR and DSC. The FTIR spectrum and DSC thermograms stated that drug and polymer are compatible to each other. The micrometric properties of drug loaded microspheres were carried out and they were found to be as the angle of repose (18.26 °-40.69 °), bulk density (0.2846-0.3875), tapped density (0.4111-0.5428), Carr's index (9.66-14.77), Hausner's ratio (1.112-1.2642) which were within the limits. In vitro dissolution, drug release was found to be from 4.5 to 6.5 h for the prepared four formulations (F1–F4). From the kinetic data modeling the order of drug release was found to be zero order and korsmeyer-peppas with n value above 0.5 for all the formulations indicating non-fickian diffusion.Conclusion: All the result demonstrated that celecoxib microspheres can be effectively used in the treatment of familial adenomatous polyposi

FTIR analysis of silane grafted high density polyethylene

Vinyltrimethoxysilane (VTMOS) monomer was grafted onto high density polyethylene by reactive processing in a twin screw extruder in the temperature range of 180-240°C. The effect of VTMOS and 1,3-bis (tert-butylperoxyisopropyl) benzene peroxide (BTBB) on the extent of grafting was studied using qualitative and quantitative Fourier transform infrared spectroscopy. The grafting reactions were confirmed via infrared absorption bands present in the 800 cm-1 region which are characteristic wavenumbers for the vibration modes of the Si-CH group from VTMOS (CH2=CH-Si-(OCH3)3). The percentage of reacted and unreacted VTMOS was calculated by a novel Fourier transform infrared spectroscopy quantitative method developed through measurements of infrared absorbance bands at peaks 795 and 814 cm-1 that are influenced by both reacted and unreacted silane. The effect of silane and peroxide concentrations on the concentration of reacted and unreacted silane present in the material was determined. The change in unsaturation content measured at absorbance 1009 cm-1 supported these findings

Extraction of the Composition of Olive Pits with Various Solvents

We have studied samples obtained from olive pits of different dimensions, determined the method for obtaining powder from olive pits, and also studied the best suitable time for collection. Crushed to a powder of powder and to particles of hard bones, they were placed in test tubes and filled with solvents. The solutions obtained by extraction with several solvents from the crushed powder of olive pits, collected in October 2021 in the Surakhani district of Baku, showed the best result. The resulting concentrates were studied and the optical density of the solutions was determined by UV spectroscopy; a method based on the Lambert–Bouguer–Beeroscopy law was applied

State of air quality in and outside of hospital wards in urban centres – A case study in Lahore, Pakistan

Particulate pollution in healthcare facilities is a potential threat to healthcare workers, patients and visitors. A study was carried out to monitor particulate levels in and outside of five wards of Sheikh Zayed Hospital, a tertiary healthcare facility of Lahore. Measurements indicated that the hourly mean concentrations of PM2.5 in a medical, pulmonology (chest), surgical, pediatric and nephrology ward were 78 ± 37, 86 ± 46, 94 ± 48, 169 ± 122 and 488 ± 314 µg m-3 respectively. The outside levels of PM2.5 of the same wards were 69 ± 27, 81 ± 49, 178 ± 85, 282 ± 164 and 421 ± 240 µg m-3. Indoor levels were higher than outdoors in all the wards except surgical and pediatric ward. Such elevated levels of PM can result in aggravation of the poor health status of the patients as well as affecting the hospital staff and visitors