Control of cone-jet geometry during electrospray by an electric current

A new electrospray system has been successfully developed by employing a proportional–integral–derivative control action to maintain an electric current at a certain value. A polymer precursor solution containing polyethylene glycol was used to examine the performance of this system. The result showed that cone-jet geometry could be controlled easily by adjusting the electric current. The length of the cone-jet decreased as the electric current was increased, in a correlation that followed power law. We also found that the cone-jet observed during electrospraying was stable and robust with no disturbance during long periods of use (up to 4000 s). The present study is very useful for further development of high precision aerosol generators and particle synthesis.     

Experimental Facilities to Monitor Various Types of Atmospheric Parameters in the Radio and Atmospheric Sciences Division (RASD) of CSIR-National Physical Laboratory

The Indian subcontinent with Himalayan Mountains on northern side, Bay of Bengal on eastern side, Arabian Sea on the western side and Indian Ocean on the southern side presents a unique natural setting with highly variable climatic features. The seasonal variation in North India is highly pronounced whereas in southern India it is moderate, the coastal areas are influenced by cyclones, north western India dominated by western disturbances and desert conditions. Added to these natural influences the rapid urbanization of regions resulted in changing atmospheric conditions leading to sudden occurrence of natural calamities. Prediction of these events requires very reliable climatic models which is a gigantic task. To develop climatic models suitable to our country, huge reliable data base of atmospheric parameters is required. Keeping this objective in view the Radio and Atmospheric Sciences Division of National Physical Laboratory has been engaged in monitoring the atmospheric parameters using various facilities with focus on northern plains. The present paper describes the latest research activities using the existing facilities and future activities and facilities planned in this division.     

Nutritional,functional, thermal and structural characteristics of <Emphasis Type="Italic">Citrullus lanatus</Emphasis> and <Emphasis Type="Italic">Limonia acidissima</Emphasis> seed flours

Seeds from fruits such as Citrullus (C.) lanatus (watermelon) and Limonia (L.) acidissima (wood apple) are not commonly utilized but could be suitable in numerous food formulations. It was shown that the protein content of defatted seed flours was 71.38 and 49.51 % and that these contained considerable amounts of minerals such as Na, Mn, Mg, K, Cu, Fe and Zn. The defatted L. acidissima seed flour was superior to C. lanatus in essential amino acids. The flours obtained from both seeds were also evaluated for functional properties and characterized by X-ray diffraction, differential scanning calorimeter and scanning electron microscope (SEM). Amorphous nature was observed in defatted C. lanatus and L. acidissima flours due to the low percentage of degree of crystallinity. Spherical morphologies were observed through SEM. The exothermic peak was recorded in defatted C. lanatus and L. acidissima flour.     

Probabilistic reliability indices evaluation of electrical distribution system accounting outage due to overloading and repair time omission

This paper presents a methodology for modifying failure rate and repair time of a distributor segment accounting the outage due to overloading and omission of critical repair time termed as repair tolerance time. Necessary relations have been derived for modifications of failure rate and repair time of a distributor and these modified failure rate/repair time have been used to evaluate average failure rate, average outage duration and average outage duration per year for distribution systems. The methodology has been implemented on a meshed distribution network and results have been compared with those obtained with unmodified failure rates/repair times.     

Line outage ranking for voltage limit violations with corrective rescheduling avoiding masking

This paper describes a technique for ranking line outages causing voltage limit violations taking into account the post-outage correctability of the network during contingency selection process. Due to the choice of large even powered of performance index (PI): (i) masking is avoided; and (ii) complete potential of correctability of power network is utilised. Fletcher and Reeves conjugate gradient method is used for optimisation. Use of newly derived compensated voltage shift factor has been made. To restrict the reactive power limit violations at generation buses, use of newly derived reactive power compensated shift factor has been made. Control corrections have been optimised for each line outage in the same base case pre-outage condition itself. This allows the use of same set of pre-outage sensitivity coefficients and line outage distribution factors. It is to be stressed here that the control corrections have been obtained for each line outage in pre-contingency condition mainly for computational convenience. But actually these corrections are applied in respective post-outage conditions. The algorithm is tested on IEEE 25-bus, 30-bus and 91-bus test systems.     

A Discrete Water Cycle Algorithm for Cellular Network Cost Management

Wireless Personal Communications - Water Cycle Algorithm (WCA) is a nature-inspired metaheuristic algorithm. There is a lack of literature surrounding the use of WCA in modern cellular mobile...     

Electrothermal Response and Functional Characteristics of Barium Ferrocyanide–Based Squibs

In an attempt to replace toxic ingredients like lead ferrocyanide (LFCN) in electrical squibs, experiments were conducted by using barium ferrocyanide (BFCN) as an ingredient of squib composition. Electrothermal response (ETR), functional characteristics such as no-fire current (NFC) and all-fire current (AFC), were studied and compared with lead ferrocyanide-based squibs. Threshold firing currents were determined using the Bruceton staircase method. The squibs were also subjected to accelerated ageing and performance was evaluated. The results indicate better performance of barium ferrocyanide squibs to electrothermal response and a higher threshold no fire current, making it comparatively safe to handle as compared to lead ferrocyanide–based squibs. The results of accelerated ageing indicate a reasonable shelf life. ETR technique is found to be a good diagnostic tool for quality control.     

Electrochemical Corrosion and Impedance Studies of Porous Ti–xNb–Ag Alloy in Physiological Solution

Porous titanium (Ti) and its alloys are promising materials for orthopedic applications due to their low elastic modulus, high strength, excellent corrosion resistance, and biocompatibility. In this study, the porous Ti–xNb–5Ag (x = 25, 30 and 35 wt%) alloys were synthesized using the powder metallurgy approach. The effects of Nb content on the porosity, mechanical properties, and electrochemical corrosion behavior of the alloys were investigated. XRD analysis revealed that the porous alloys mainly consist of α-Ti, β-Ti, intermetallic compound (Ti₄Nb), and oxides of TiO₂ and NbO phases. Porous alloys possess the porosity ranging from 57 to 65%, due to the addition of NH₄HCO₃ (45 wt%). Increase in Nb content lead to a reduction in the elastic modulus and compression strengths of the sintered porous Ti–xNb–5Ag alloys. All three developed porous Ti–xNb–5Ag alloys show the optimum combination of elastic modulus and compression strength, which is suitable for orthopedic applications. These porous alloys exhibit excellent electrochemical corrosion resistance in the simulated body fluids, and the samples having low porosity exhibit higher corrosion resistance than high-porosity samples.