Microstructural developments and mechanical properties of friction stir welding of AZ91D magnesium alloy plates

Friction stir welding (FSW) is an efficient technique which can be used particularly for magnesium and aluminum alloys that are difficult to fusion weld. In this work AZ91D Mg alloy plates 3mm thick were friction stir welded at different process variables such as rotational speed and welding speed. The range of rotational speeds varied from 1025 to 1525 rpm, and the welding speed varied from 25 to 75 mm/min. Good quality welds were obtained under 1025 rpm of rotational speed with the welding speeds range from 25 to 75 mm/min. The microstructure of the AZ91D alloy consists of primary α-phase, eutectic α-phase and eutectic β (Mg17Al12) phase in the received condition (gravity die cast). The original dendrite grain structure completely disappeared and was transformed to fine equiaxed grains in stir zone (SZ). It was observed that there was a slight increase in hardness in SZ, because of fine recrystallized grain structure. The transverse tensile test results of weld specimens indicated constant strength irrespective of traveling speed. Fractrographic analysis of the friction stir welded specimens showed the brittle failure

Pascal distribution series related to starlike functions with respect to other points

The aim of the present paper is to find the necessary and sufficient conditions for subclasses of starlike functions with respect to symmetric points, starlike functions with respect to conjugate points, starlike functions with respect to symmetric conjugate points associated with Pascal distribution series and inclusion relations for such subclasses in the open unit disk U. Further, we consider an integral operator related to Pascal distribution series.

Epidural Volume Extension in Combined Spinal Epidural Anaesthesia in Pregnant Patients Coming for Elective Cesarean Section with Routine Spinal Anaesthesia: A Comparative Study

AIM OF THE STUDY: To evaluate the effects of Epidural volume extension with Normal saline given along with Hyperbaric bupivacaine in combined spinal epidural technique for parturients planned for elective cesarean section to achieve adequate anaesthesia with better hemodynamic stability and early reversal of motor blockade. METHOD: 60 term parturients were enrolled in the study and were randomly allocated into one of the 2 groups comprising 30 in each. One Group (Group E) received epidural volume extension with 6mL of normal saline along with 5mg of 0.5% hyperbaric bupivacaine plus 25 mcg fentanyl and the other Group (Group C) received only spinal anesthesia with 10mg of 0.5% hyperbaric bupivacaine plus 25 mcg fentanyl. Haemodynamics, peak sensory block height, time of regression of sensory blockade, degree and duration of motor blockade, ephedrine consumption, neonatal scores, nausea, vomiting, time to first analgesic supplement required were noted and compared between the two groups. STATISTICAL ANALYSIS: Done using SPSS software version 17.0 using student T test. RESULTS: Systolic blood pressures after the 20th min of initiation of spinal blockade were significantly higher in Group E compared to Group C, till the 40th min. (P values for the 20th, 25th, 30th and 40th min respectively were 0.001, <0.001, 0.002, 0.012). ephedrine consumption was significantly higher in Group C (P 0.042). Motor blockade regressed sooner in Group E compared to group C (P<0.001). Other monitored parameters were similar in both groups. CONCLUSION: Epidural volume extension with normal saline in combined spinal epidural anaesthesia provides a hemodynamically stable anaesthesia with reduced duration of motor blockade without compromising the duration and quality of anaesthesia and with no adverse fetal effects, for elective cesarean section. These benefits are obtainable at a reduced dose of intrathecal local anaesthetic

Rearing performance of tropical Tasar silkworm (Antheraea mylitta Drury) on Cashew (Anacardium occidentale L.) and its commercial silk properties

Tasar silkworm, Antheraeamylitta Drury (Lepidoptera: Saturniidae) is one of the commercially exploited non-mulberry silkworms mainly reared outdoor on many wild plants. The ecorace of tasar silkworm occurring in cashew (Anacardiumoccidentale L.) plantations of Puttur was identified as A. mylitta KE-02. Pooled egg, larval and pupal period of tasar silkworm upon indoor rearing on cashew recorded were 6.43, 28.69 and 25.36 days, respec-tively, with the effective rate of rearing of 40 %. The average cocoon weight, pupal weight and shell weight recorded were 6.24 g, 5.30 and 1.18 g, respectively. The high shell ratio of 22.26 %, shows a healthy trend for high yielding tasar rearing on cashew. The commercial silk properties of cashew reared cocoons were assessed in comparison to silk properties of cocoons reared on Terminalia paniculata. Average filament length, average non-breakable filament length, denier, strength and elongation were found 547.2 m, 1231.6 m, 8.92 D, 1.57 gpd and 16.9 %, respectively on cashew and 518.2 m, 161.94 m, 9.13 D, 1.73 gpd and 18.7 % , respectively on T. paniculata. The present study has documented the biology of tasar silk worm on cashew and also the commercial silk properties of cocoon reared on cashew at preliminary level

Electronic phase separation in the rare earth manganates, (La1-xLnx)0.7Ca0.3MnO3 (Ln = Nd, Gd and Y)

All the three series of manganates showsaturation magnetization characteristic of ferromagnetism, with the ferromagnetic Tc decreasing with increasing in x up to a critical value of x, xc (xc = 0.6, 0.3, 0.2 respectively for Nd, Gd, Y). For x > xc, the magnetic moments are considerably smaller showing a small increase around TM, the value of TM decreasing slightly with increase in x or decrease in . The ferromagnetic compositions (x xc) show insulator-metal (IM) transitions, while the compositions with x > xc are insulating. The magnetic and electrical resistivity behavior of these manganates is consistent with the occurrence of phase separation in the compositions around xc, corresponding to a critical average radius of the A-site cation, , of 1.18 A. Both Tc and TIM increase linearly when < rA > > or x xc as expected of a homogenous ferromagnetic phase. Both Tc and TM decrease linearly with the A-site cation size disorder at the A-site as measured by the variance s2. Thus, an increase in s2 favors the insulating AFM state. Percolative conduction is observed in the compositions with > < rAc >. Electron transport properties in the insulating regime for x > xc conforms to the variable range hopping mechanism. More interestingly, when x > xc, the real part of dielectric constant (e') reaches a high value (104-106) at ordinary temperatures dropping to a very small (~500) value below a certain temperature, the value of which decreases with decreasing frequency.Comment: 27 pages; 11 figures, Submitted to J.Phys:Condens Matte

QUALITY BY DESIGN APPROACH TO STABILITY-INDICATING REVERSE-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY METHOD DEVELOPMENT, OPTIMIZATION, AND VALIDATION FOR THE ESTIMATION OF SIMEPREVIR IN BULK DRUG:

Objective: A simple, robust, precise, and selective stability-indicating liquid chromatography (LC) method (reverse-phase high-performance LC) was developed for the estimation of simeprevir through quality by design paradigm. Methods: The chromatographic separation was performed on Water’s 2695(Alliance) equipped with a photodiode array detector at 300 nm. The method was developed on Discovery C18 column (250×4.6, 5 mm) using orthophosphoric acid and acetonitrile (55:45 % v/v) with the flow rate of 1 ml/min at 30°C. The degradation studies of simeprevir were carried out under the stress conditions of hydrolysis (acid, base, and neutral), oxidation, photolytic, and thermal as per the International Conference on Harmonization (ICH) guidelines. The peroxide hydrolysis shows more critical impurities which were well resolved from pure drug with the application of design of experiment and optimized the method. Results: Independent variables (critical analytical attributes) selected for the method optimization were mobile phase ratio, flow rate, and temperature of the column based on the risk assessment. The retention time and resolution were selected as the method response. In response surface method, the central composite design and 23 factorial designs were employed for the optimization of the method. The polynomial equation was derived for the estimation of method response. Conclusion: The method was optimized for better resolution among the drug, and impurity peaks were then validated as per the ICH parameters