Anomalous Thermoelectric power of over-doped Bi2Sr2CaCu2O8 superconductor

Temperature dependence of thermoelectric power S(T) of three differently processed Bi2Sr2CaCu2O8 (Bi2212) samples, viz. as-processed melt quenched (Bi2212-MQ), 6000C N2-annealed (Bi2212-N2) and 6000C O2-annealed (Bi2212-O2) is reported here. All the samples possess single-phase character and their superconducting transition temperatures (TcR=0) are 85 K, 90 K and 72 K respectively for Bi2212-MQ, Bi2212-N2 and Bi2212-O2. While Bi2212-MQ and Bi2212-N2 samples are in near optimum doping regime, Bi2212-O2 is an over-doped sample. TcS=0 values obtained through S(T) data are also in line with those deduced from the temperature dependence of resistance and DC magnetization. Interestingly, S(T) behaviour of the optimally-doped Bi2212-MQ and Bi2212-N2 samples is seen to be positive in whole temperature range, it is found negative for the over-doped Bi2212-O2 sample above TcS=0. These results have been seen in the light of the recent band structure calculations and the ensuing split Fermi surface as determined by angle-resolved photoelectron spectroscopy (ARPES).Comment: 11 Pages Text + Figs: comments welcome ([email protected]

Millimeter Wave Technology for Armament Applications .

Use of millimeter wave (MMW) technology in armament systems imposes many restrictions on the size, volume and compactness of these systems in addition to ruggedness and reliable functioning in battlefield environment. This paper discusses the related design and technological issues, particularly in, the context of the sensors developed for smart ammunition and active armour protection systems

Analysis of MAGSAT data of the Indian region

Progress in the development of software for reading MAGSAT data tapes and for the reduction of anomaly data, and in the preparation of data for magnetic anomaly maps is reported

Of mice and mates:Automated classification and modelling of mouse behaviour in groups using a single model across cages

Behavioural experiments often happen in specialised arenas, but this may confound the analysis. To address this issue, we provide tools to study mice in the home-cage environment, equipping biologists with the possibility to capture the temporal aspect of the individual’s behaviour and model the interaction and interdependence between cage-mates with minimal human intervention. Our main contribution is the novel Global Behaviour Model (GBM) which summarises the joint behaviour of groups of mice across cages, using a permutation matrix to match the mouse identities in each cage to the model. In support of the above, we also (a) developed the Activity Labelling Module (ALM) to automatically classify mouse behaviour from video, and (b) released two datasets, ABODe for training behaviour classifiers and IMADGE for modelling behaviour

Esophageal Cancer Recurrence Patterns and Implications for Surveillance

Introduction:After definitive treatment of esophageal cancer, patients are at high risk for recurrence. Consistent follow-up is important for detection and treatment of recurrence. The optimal surveillance regimen remains undefined. We investigated posttreatment recurrence patterns and methods of detection in survivors of esophageal cancer.Methods:We retrospectively studied a cohort of patients who had undergone surgical resection for esophageal cancer at our institution between 1996 and 2010. Routine computed tomography scan and upper endoscopy were performed for surveillance.Results:In total, 1147 patients with resected esophageal adenocarcinoma or squamous cell carcinoma were included (median follow-up, 46 months). Of these, 723 patients (63%) had received neoadjuvant therapy before surgery. During follow-up, there were 595 deaths (52%) and 435 recurrences (38%) (distant [55%], locoregional [28%], or both [17%]). Half of recurrences were detected as a result of symptoms (n = 217), 45% by routine chest and abdominal computed tomography scan (n = 194), and 1% by surveillance upper endoscopy (n = 6). The recurrence rate decreased from 27 per 100 person-years in posttreatment year 1 to 4 per 100 person-years in year 6. In the first 2 years, the rate of recurrence was higher among patients who had received neoadjuvant therapy (35 per 100 person-years) than among those who had not (14 per 100 person-years) (p < 0.001).Conclusions:The incidence of recurrence is high after esophagectomy for cancer. Surveillance endoscopy has limited value for detection of asymptomatic local recurrence. The yield from follow-up scans diminishes significantly after the sixth year; surveillance scans after that point are likely unnecessary

Radio continuum properties of young planetary nebulae

We have selected a small sample of post-AGB stars in transition towards the planetary nebula and present new Very Large Array multi-frequency high-angular resolution radio observations of them. The multi-frequency data are used to create and model the targets' radio continuum spectra, proving that these stars started their evolution as very young planetary nebulae. In the optically thin range, the slopes are compatible with the expected spectral index (-0.1). Two targets (IRAS 18062+2410 and 17423-1755) seem to be optically thick even at high frequency, as observed in a handful of other post-AGB stars in the literature, while a third one (IRAS 20462+3416) shows a possible contribution from cold dust. In IRAS 18062+2410, where we have three observations spanning a period of four years, we detect an increase in its flux density, similar to that observed in CRL 618. High-angular resolution imaging shows bipolar structures that may be due to circumstellar tori, although a different hypothesis (i.e., jets) could also explain the observations. Further observations and monitoring of these sources will enable us to test the current evolutionary models of planetary nebulae.Comment: 8 pages, 3 figures, accepted for publication in MNRA

Synthesis of biomedical Ti-25Ni-15Si-10HA alloy by mechanical alloying and spark plasma sintering

In this research approach, a β-phase titanium alloy was produced successfully employing mechanical alloying and consolidated with spark plasma sintering (SPS) process. Herein, Ni, Si and HA powders with varied weight percentage were used to fabricate the Ti alloy. The influence of HA addition on microstructure of the alloy was assessed using optical microscopy route and further amplified using field emission scanning electron microscopy (FESEM). The elemental composition and phase of Ti-alloy was investigated using x-ray diffractometer. Vicker hardness (HV) tester was employed to estimate the micro hardness of the specimen surface. During the FESEM analysis, it was observed that within the sintering process, alloy exhibits complex reactions with HA, which leads to the progress of bioactive compounds (CaO, TiO2, Ca3 (PO4)2, Ti2Ni, CaTiO3 and CaTiSiO5) enhancing the bioactivity of the Ti alloy. The fabricated Ti alloy (Ti-25Ni-15Si-10HA) exhibited superior microhardness (~458HV) at 900°C, comparative to the other alloys of the native category. Based upon the current investigation, Ti-25Ni-15Si-10HA alloy could find applications as bioimplants in dental and orthopedic areas

Synthesis of biomedical Ti-25Ni-15Si-10HA alloy by mechanical alloying and spark plasma sintering

In this research approach, a β-phase titanium alloy was produced successfully employing mechanical alloying and consolidated with spark plasma sintering (SPS) process. Herein, Ni, Si and HA powders with varied weight percentage were used to fabricate the Ti alloy. The influence of HA addition on microstructure of the alloy was assessed using optical microscopy route and further amplified using field emission scanning electron microscopy (FESEM). The elemental composition and phase of Ti-alloy was investigated using x-ray diffractometer. Vicker hardness (HV) tester was employed to estimate the micro hardness of the specimen surface. During the FESEM analysis, it was observed that within the sintering process, alloy exhibits complex reactions with HA, which leads to the progress of bioactive compounds (CaO, TiO2, Ca3 (PO4)2, Ti2Ni, CaTiO3 and CaTiSiO5) enhancing the bioactivity of the Ti alloy. The fabricated Ti alloy (Ti-25Ni-15Si-10HA) exhibited superior microhardness (~458HV) at 900°C, comparative to the other alloys of the native category. Based upon the current investigation, Ti-25Ni-15Si-10HA alloy could find applications as bioimplants in dental and orthopedic areas