Photon redshift and the appearance of a naked singularity

In this paper we analyze the redshift as observed by an external observer receiving photons which terminate in the past at the naked singularity formed in a Tolman-Bondi dust collapse. Within the context of models considered here it is shown that photons emitted from a weak curvature naked singularity are always finitely redshifted to an external observer. Certain cases of strong curvature naked singularities, including the self-similar one, where the photons are infinitely redshifted are also pointed out.Comment: Latex file, 14 pages, no figures, one change in the reference. Accepted for publication in Phys. Rev.

Bianchijev kozmološki model tipa-III sa strunama, volumnom viskoznošću i promjenljivim članom Λ

We study Einstein’s field equations in Bianchi type-III string cosmological models with bulk viscosity and variable cosmological term Λ. Exact solutions of the field equations are obtained by assuming the conditions: the bulk viscosity is proportional to the expansion scalar, ξ ∝ θ, expansion scalar is proportional to shear scalar, θ ∝ σ, and Λ is proportional to the Hubble parameter. The corresponding physical interpretations of the cosmological solutions are also discussed.Proučavamo Einsteinove jednadžbe polja u Bianchijevim kozmološkim modelima tipa III sa strunama, volumnom viskoznošću i promjenljivim kozmološkim članom Λ. Postigli smo egzaktna rješenja jednadžbi polja pretpostavivši uvjete: volumna viskoznost je razmjerna skalaru širenja, ξ ∝ θ, skalar širenja je razmjeran skalaru posmika, θ ∝ σ, i Λ je razmjerno Hubbleovom parametru. Raspravljaju se fizikalna tumačenja kozmoloških rješenja

Bianchijev kozmološki model tipa-III sa strunama, volumnom viskoznošću i promjenljivim članom Λ

We study Einstein’s field equations in Bianchi type-III string cosmological models with bulk viscosity and variable cosmological term Λ. Exact solutions of the field equations are obtained by assuming the conditions: the bulk viscosity is proportional to the expansion scalar, ξ ∝ θ, expansion scalar is proportional to shear scalar, θ ∝ σ, and Λ is proportional to the Hubble parameter. The corresponding physical interpretations of the cosmological solutions are also discussed.Proučavamo Einsteinove jednadžbe polja u Bianchijevim kozmološkim modelima tipa III sa strunama, volumnom viskoznošću i promjenljivim kozmološkim članom Λ. Postigli smo egzaktna rješenja jednadžbi polja pretpostavivši uvjete: volumna viskoznost je razmjerna skalaru širenja, ξ ∝ θ, skalar širenja je razmjeran skalaru posmika, θ ∝ σ, i Λ je razmjerno Hubbleovom parametru. Raspravljaju se fizikalna tumačenja kozmoloških rješenja

Kantowski-Sachsovi kozmološki modeli s vremenski-promjenljivim G i Λ

Kantowski-Sachs cosmological models with perfect fluid and time varying G and Λ are presented. Exact solutions of the field equations are obtained by using the scalar of expansion proportional to the shear scalar θ ∝ σ, which leads to a relation between the metric potentials A = Bn, where n is a constant. The corresponding physical interpretation of the cosmological solutions are also discussed.Predstavljamo Kantowski-Sachsove kozmološke modele s vremenski-promjenljivim G i Λ koji sadrže perfektnu tekućinu. Izvodimo egzaktna rješenja jednadžbi polja primjenom skalara razvoja koji je razmjeran posmičnom skalaru, θ ∝ σ, što vodi na relaciju među metričkim potencijalima A = Bn, gdje je n stalan. Raspravljamo i fizičko tumačenje kozmoloških rješenja

Kantowski-Sachsovi kozmološki modeli s vremenski-promjenljivim G i Λ

Kantowski-Sachs cosmological models with perfect fluid and time varying G and Λ are presented. Exact solutions of the field equations are obtained by using the scalar of expansion proportional to the shear scalar θ ∝ σ, which leads to a relation between the metric potentials A = Bn, where n is a constant. The corresponding physical interpretation of the cosmological solutions are also discussed.Predstavljamo Kantowski-Sachsove kozmološke modele s vremenski-promjenljivim G i Λ koji sadrže perfektnu tekućinu. Izvodimo egzaktna rješenja jednadžbi polja primjenom skalara razvoja koji je razmjeran posmičnom skalaru, θ ∝ σ, što vodi na relaciju među metričkim potencijalima A = Bn, gdje je n stalan. Raspravljamo i fizičko tumačenje kozmoloških rješenja

Techno-Economic Analysis of Hybrid Layered Manufacturing

Subtractive manufacturing (CNC machining) has high quality of geometric and material properties but is slow, costly and infeasible in some cases; additive manufacturing (RP) is just the opposite. Total automation and hence speed is achieved in RP by compromising on quality. Hybrid Layered Manufacturing (HLM) developed at IIT Bombay combines the best features of both these approaches. It uses arc welding for building near-net shapes which are finish machined to final dimensions. High speed of HLM surpasses all other processes for tool making by eliminating NC programming and rough machining. The techno-economic viability of HLM process has been proved through a real life case study. Time and cost of tool making using HLM promises to be substantially lower than that of CNC machining and other RP methods. Interestingly, the material cost in HLM was also found to be lower. HLM is a cheaper retrofitment to any 3 or 5 axis CNC milling machine or machining center.Mechanical Engineerin

Polyherbal Formulation used in the Treatment of Jaundice

Plants have traditionally served as man\u27s most important weapon against pathogens. Herbal medicines are widely used by all sections of the community, either as folk remedies or as medicaments in the indigenous as well as modern system of medicine. The present work was performed to enumerate the medicinal herbs that tribes and rural people uses for the treatment of jaundice. Data were collected by interviewing local traditional therapists and tribes of the region. Details of 10 herbs and 03 formulations were gathered along with their doses, duration and formulations during the course of present investigation in the study area. Our study revealed that all above herbs and their formulations have been used since quite a long time by the tribes and rural people and no side/ adverse effects were reported

Formulation and Evaluation of Polyherbal Anthelmintic Preparation

The present study was done with the aim to formulate an anthelmintic preparation and to evaluate anthelmintic activity of formulation containing traditionally user herbs viz., Plumbago zeylanica (leaves), Hyoscyamus niger (roots) and Abultion indicum (leaves) using adult earthworm Pheritima posthuma. The aqueous and ethanolic extract of the crude drug of different concentration were tested which involve determination of paralysis time and time to kill the worms. Piperazine citrate was used as standard and it was found that the PHFEE activity is higher than PHFAE

Anthelmintic Activity of a Polyherbal Preparation

The present study was done with the aim to investigate the anthelmintic activity of polyherbal formulation containing herbs Thespesia populnea (bark), Terminalia alata (bark), Clematis triloba (roots) and Ceratophyllum demersum (leaves) using adult earthworm Pheritima posthuma. The aqueous and ethanolic extract of the crude drug of different concentration were tested which involve determination of paralysis time and time to kill the worms. Piperazine citrate was used as standard and it was found that the PHF ethanolic extract activity is higher than PHF aqueous extract

Effect of agro-input management practices on yield of linseed (Linum usitatissimum L.) under vertisols of Chhattisgarh, India

A field experiment was conducted to study the effect of agro-input management practices on yield of linseed (Linum usitatissimum L.) at the Instructional cum Research Farm, Indira Gandhi Krishi Vishwavidyalaya, Raipur, (C.G.) during Rabi 2015-16. Different agro input management practices had significant (P=0.05) effect on growth, yield attributes and yield of linseed. However, seed rates did not give significant influence on seed yield. Whereas, application of RDF + FYM placement in rows @ 5 t ha-1 (N3) recorded significantly (P=0.05) higher growth parameters viz. plant height (88.44 cm), primary branches plant-1 (3.83), secondary branches plant-1 (23.39), dry matter accumulation (6.76 g plant-1) and yield attributes viz. capsules plant-1 (30.86), seeds capsule-1(7.63), seeds plant-1 (235.32), seed yield (2100 kg ha-1) and stover yield (4885 kg ha-1). In case of foliar spray, application of 2 % urea at 15, 40, 65 and 90 DAS (F3) gave significantly higher growth parameters viz. plant height (88.37 cm), primary branches plant-1(3.82), secondary branches plant-1 (23.68), dry matter accumulation (6.59 g plant-1) and yield attributes viz. capsules plant-1(31.74), seeds capsule-1(7.63), seeds plant-1 (241.38), seed yield (2089 kg ha-1) and stover yield (4772 kg ha-1). Interaction among seed rate 30 kg ha-1 (S2) X RDF 60:30:30 N: P: K kg ha-1 (N1) with foliar application of 2 % urea at 15, 40, 65 and 90 DAS (F3) (S2 XN1X F3) recorded the highest benefit-cost ratio (4.39). Line placement of FYM was better than broadcasting in terms of seed yield; and foliar application of urea was economical than Nitrobenzene