Determination of Thermo-Electrical Properties in Sn Based Alloys

Sezen Aksöz,Yavuz Ocak,Kâzlm Keslioslu,Necmettin Mara ll 대한금속·재료학회 2010 METALS AND MATERIALS International Vol.16 No.3

The variation of thermal conductivity of solid phase versus temperature for Sn-21 wt.% Bi, Sn-25 wt.% In and Sn-35 wt.% In-26 wt.% Bi alloys were measured with a radial heat flow apparatus. From the graphs of thermal conductivity versus temperature, the thermal conductivity of the solid phases at their melting temperatures and the thermal temperature coefficients for the same alloys were obtained. The ratios of thermal conductivity of liquid phase to solid phase for the same materials were measured with a Bridgman type directional solidification apparatus. The variations of electrical conductivity of solid phases versus temperature for the same alloys were determined from the Wiedemann-Franz law by using the measured values of thermal conductivity. From the graphs of electrical conductivity versus temperature, the electrical temperature coefficients for the same alloys were also determined. According to present experimental results it can be concluded that the thermal and electrical conductivity of Sn based alloys depend on the thermal and electrical conductivity of the alloying elements. If the thermal and electrical conductivity of the alloying elements are lower than the thermal conductivity of Sn, the thermal conductivity of Sn based alloys decreases, whereas, otherwise,it increases.

Determination of Interfacial Energies for Solid Al Solution in Equilibrium with Al-Cu-Ag Liquid

K. Ke lio lu,Y. Ocak,S. Aksöz,N. Mara ll,E. Çadlrll,H. Kaya 대한금속·재료학회 2010 METALS AND MATERIALS International Vol.16 No.1

The equilibrated grain boundary groove shapes of a solid Al solution in equilibrium with Al-Cu-Ag liquid were observed from a quenched sample using a radial heat flow apparatus. The Gibbs-Thomson coefficient,solid-liquid interfacial energy, and grain boundary energy of the solid Al solution were determined from the observed grain boundary groove shapes. The thermal conductivity of the solid phase for Al-16.42 at.% Ag-4.97at.% Cu and Al-16.57 at.% Ag-11.87 at.% Cu alloys and the thermal conductivity ratio of the liquid phase to the solid phase for Al-16.57 at.% Ag-11.87 at.% Cu alloy at the melting temperature were also measured with a radial heat flow apparatus and a Bridgman-type growth apparatus, respectively.

Experimental Determination of Interfacial Energies for Solid Sn in Equilibrium with Sn-Mg-Zn Liquid

Yemliha Altıntas,Esra Öztürk,Sezen Aksöz,Kâzım Keşlioğlu,Necmettin Maraşlı 대한금속·재료학회 2015 METALS AND MATERIALS International Vol.21 No.2

The equilibrated grain boundary groove shapes of solid Sn in equilibrium with Sn-Mg-Zn liquid were observedfrom a quenched sample by using a radial heat flow apparatus. The Gibbs-Thomson coefficient, solid-liquidinterfacial energy and grain boundary energy of solid Sn were determined from the observed grain boundarygroove shapes. The thermal conductivity of the eutectic solid phase for Sn-8.12 at% Mg-4.97 at% Zn alloy and thethermal conductivity ratio of the liquid phase to the solid phase for Sn-8.12 at% Mg-4.97 at% Zn alloy at eutectictemperature were also measured with a radial heat flow apparatus and a Bridgman-type growth apparatus,respectively. The Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy of solidSn in equilibrium with Sn-Mg-Zn liquid were determined to be (8.3 ± 0.6)×10-8 Km, (118.5 ± 14.2)×10-3 Jm-2and (225.1 ± 29.3)×10-3 J m-2 respectively from observed grain boundary groove shapes. A comparison ofpresent results for solid Sn in the Sn-8.12 at% Mg-4.97 at% Zn alloy with the results obtained in previous worksfor similar solid Sn in equilibrium with different binary or ternary liquid was made.

Comparison and selection of patient follow‑up systems for covid‑19 pandemic patients

Tamer Eren,Tuğba Danışan,Ayşegül Deringöz,Güler Aksüt 한국의류학회 2022 Fashion and Textiles Vol.9 No.1

People have struggled with many infectious diseases throughout history. Today, the Covid-19 is being fought. One of the most important things for people who have or are at risk of getting Covid-19 is social isolation. Many countries resort to diferent ways to ensure social isolation. For this, remote patient monitoring systems have been developed. In this study, the problem of the selection of Covid-19 remote patient monitoring systems is discussed. Seven Wearable Health Technology (WHT) products were evaluated with a total of 10 criteria, including the important symptoms used in the patient tracking systems. The weights of 10 criteria determined by the Analytical Hierarchy Process (AHP) method were calculated, and these weights were used in the solution of The Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE), and Technique for Order Preference by Similarity to Ideal Solutions (TOPSIS) methods. WHT products were compared. As a result, the most appropriate patient follow-up system was determined. This study generates diferences in terms of evaluating seven diferent products and ten criteria in total with MCDM methods. A more comprehensive evaluation has been made in the literature than the studies in this feld.

Antimicrobial Studies of Stem of Different Berberis Species

Meenakshi Singh,Sharad Srivastava,AKS Rawat 한국생약학회 2009 Natural Product Sciences Vol.15 No.2

Berberis is an important medicinal plant, of the family Berberidaceae. Different Berberis species and their parts are very common in herbal drug markets of India and world over as an adulterant/substitute to ‘Daruharidra’ i.e. B. aristata DC. Antimicrobial activity of 50% hydroalcoholic extracts of stem of four Berberis species viz. B. aristata DC., B. asiatica Roxb. ex DC., B. chitria Lindl. and B. lycium Royle and the isolated alkaloid berberine were tested against eleven bacterial and eight fungal strains. The extracts with the strongest antibacterial activity was obtained from B. lycium followed by B. aristata, B. asiatica and B. chitria. Based on these results it is possible to conclude that the hydroalcoholic extract and alkaloid (berberine) has stronger and broader spectrum against bacterial strains as compared to fungal strains. The result obtained in the present study authenticates and support the use of these plants in folklore medicine for treatment of various infectious diseases caused by the bacterial pathogens. However, an attempt has been made to explore the possibilities of utilizing stem part rather than roots of these species with the aim to conserve this species which is over exploited due to diverse use of its root. These findings will stimulate the search for novel, natural products as new antibacterial/ antifungal agents which may be useful to pharmaceutical industries.

Pharmacognostic Evaluation of Curcuma caesia Roxb. rhizome

Durgesh Verma,,Sharad Srivastava,Vineet Singh,AKS Rawat 한국생약학회 2010 Natural Product Sciences Vol.16 No.2

Curcuma caesia Roxb. (Zingiberaceae) is commonly known as `Black turmeric'. In India it grows in West Bengal, Madhya Pradesh, Orissa, Bihar, North-East and Uttar Pradesh and is widely used by ethnic communities for various ailments. Rhizomes of the plant are used for sprains and bruises and are also employed in cosmetics. In West Bengal it is an important place in traditional system of medicine and is also used as a substitute for turmeric in fresh stage. Present communication deals with the detailed pharmacognostical evaluation of the rhizome sample. Inner part of the rhizome is bluish-black in colour and emits a characteristic sweet smell, due to the presence of essential oil. On steam distillation the rhizome yields an essential oil rich in camphor. A detailed HPTLC studies has been carried out for quantitative evaluation of active marker component. HPTLC, physico-chemical, morphological and histological parameters presented in this paper may be proposed as parameters to establish the authenticity of C. caesia rhizome and may possibly help to differentiate the drug from its other allied species.

Pharmacognostical Evaluation and Phytochemical Standardization of Abrus precatorius L. Seeds

Durgesh Verma,Shashi Shankar Tiwari,Sharad Srivastava,AKS Rawat 한국생약학회 2011 Natural Product Sciences Vol.17 No.1

The seeds of Abrus precatorius L. (Family- Fabaceae) constitute the drugs Abrus, Gunja, or Ratti in commerce. In the Indian System of Medicine, the seeds are used for sciatica, paralysis, headache, dysentery, diarrhoea, leprosy, ulcer, nervous disorders, alopecia, as well as anti-inflammatory, antidiabetic, antibacterial, antitumor, sexual stimulant and abortifacient. Seeds are poisonous and therefore are used after mitigation. The protein abrin is responsible for the highly toxic properties of seeds. Quantitative HPTLC analysis of the methanolic extract of seeds determined the presence of 0.4018% gallic acid and 0.4009% glycyrrhizin. The present study was undertaken to develop an HPTLC method, as well as ascertain the physico-chemical, morphological and histological parameters to establish the authenticity of A. precatorius seeds.

Pharmacognostic Evaluation of Curcuma aeurigenosa Roxb.

Sharad Srivastava,Nitin Chitranshi,Sanjay Srivastava,Mathew Dan,AKS Rawat,Palpu Pushpangadan 한국생약학회 2006 Natural Product Sciences Vol.12 No.3

aeruginosa Roxb. (FamilyZingeberaceae), comonly known as “pink and blue ginger” iscultivated in southern India. The plant is distinguished by red corolla lobes and ferruginous or greenish-bluerhizome. Rhizoma is used medicinally as anti-diarrheal, anti-fungal; external use as astringent for wounds. Adetailed pharmacognostic evaluation of its rhizome showed total ash 6.1%, acid insoluble ash 1.20%, alcoholsoluble extractives 3.70%, water soluble extractives 14.50%, sugar 20.93%, starch 41.85%, and tannins 0.68%.On hydro distillation, the rhizomes and sesile tubers yielded 0.17% oil.KeywordsCurcuma aueriginosa, rhizome, pharmacognosy, standardization

Pharmacognostic Evaluation of Pipper longum Linn. Fruit

Manjoosha Srivastava,Meenu Gupta,Sharad Srivastava,Shanta Mehrotra,Vinita Sharma,AKS Rawat 한국생약학회 2007 Natural Product Sciences Vol.13 No.2

present study includes macro and microscopical details, powder study, physico-chemical studyand HPTLC fingerprinting of the Piper longum fruits. Microscopic studies revealed the presence of stone cells,starch grains and thin walled fragments of parenchymatous cells. Physico-chemical studies showed alcohol andether soluble extract 24.53 and 6.7, sugar 0.35, starch 21.33 and tannin 0.83% respectively. Successive soxhletextract showed maximum percentage of hexane soluble fraction i.e. 22.52. The HPTLC profile has also beenperformed against the reference marker piperine, which was identified at Rf 0.42. pharmacognostical evaluation of fruit has been undertaken.KeywordsPiper longum, Pharmacognosy, HPTLC.

RELAXX(Sports and Leisure Center)

AK2 Architectural Studio 현대건축사 2009 월간 CONCEPT Vol.- No.118