Finite element modelling of natural vibration problems

Finite element models of Modified Rayleigh-Ritz, Galerkin, Least Square, Hybrid (Pian's) and Collocation methods are presented for natural vibration problems. A comparative assessment is made of these methods with Rayleigh-Ritz finite element models. This study brings out that the Galerkin model is relatively superior. A method of improving the accuracy in the estimation of eigenvalues is also included

Functional outcome of anterior cruciate ligament reconstruction using bone-patellar tendon-bone graft: a descriptive observational study from Telangana

Background: The knee joint is the most commonly injured of all joints and the anterior cruciate ligament is the most commonly injured ligament. The bone-patellar tendon-bone (BPTB) autograft is the most commonly used autograft for reconstruction. The bone-patellar tendon-bone autograft has been widely accepted as the gold standard for ACL reconstruction with a high success rate. Objectives of the study were to study the functional outcome of ACL reconstruction using BPTB graft.Methods: The present descriptive observational study was carried out at department of orthopedics, Mediciti institute of medical sciences, Hyderabad involving 30 patients of ACL tear by simple random sampling method. Patients were then evaluated by both subjectively and objectively. They were evaluated by using Lysholm and Gilquist knee scoring scale. Data was analyzed by using SPSS 24.0 version IBM USA.Results: Majority of the patients i.e., 13 (43.3%) were from 26-35 years age group with right sided involvement in 60%. The result was found to be good in 16 i.e., 53.3%, excellent in 10 i.e., 33.3% and fair in 4 i.e., 13.3% patients. Prevalence of complications was reported as 23.3% in our study.Conclusions: Our study of ACL repair using BPTP gives good to excellent results within a span of one year

Geomagnetic storm effects on GPS based navigation

The energetic events on the sun, solar wind and subsequent effects on the Earth's geomagnetic field and upper atmosphere (ionosphere) comprise space weather. Modern navigation systems that use radio-wave signals, reflecting from or propagating through the ionosphere as a means of determining range or distance, are vulnerable to a variety of effects that can degrade the performance of the navigational systems. In particular, the Global Positioning System (GPS) that uses a constellation of earth orbiting satellites are affected due to the space weather phenomena. <br><br> Studies made during two successive geomagnetic storms that occurred during the period from 8 to 12 November 2004, have clearly revealed the adverse affects on the GPS range delay as inferred from the Total Electron Content (TEC) measurements made from a chain of seven dual frequency GPS receivers installed in the Indian sector. Significant increases in TEC at the Equatorial Ionization anomaly crest region are observed, resulting in increased range delay during the periods of the storm activity. Further, the storm time rapid changes occurring in TEC resulted in a number of phase slips in the GPS signal compared to those on quiet days. These phase slips often result in the loss of lock of the GPS receivers, similar to those that occur during strong(>10 dB) L-band scintillation events, adversely affecting the GPS based navigation

Prevalence of thyroid dysfunction and its association with controlled and uncontrolled type 2 diabetes mellitus in northern Andhra Pradesh population: a retrospective study

Background: The two important endocrinopathies, diabetes mellitus and thyroid dysfunction are interrelated to each other where the correlation is poorly understood. The thyroid dysfunction is more frequent in diabetics than general population. The present study was aimed to know the prevalence of thyroid dysfunction in type 2 diabetes mellitus (T2DM) and its association with controlled and uncontrolled T2DM.Methods: A retrospective study of 600 T2DM patients between 13-60 years of age with known thyroid status were included and the following parameters were examined: age, sex, body mass index (BMI), fasting blood sugar (FBS), HbA1C, free triiodothyronine (fT3), free tetraiodothyronine (fT4) and thyroid stimulating hormone (TSH).Results: The prevalence of thyroid dysfunction in T2DM patients was found to be 26.5% whereas 9% in healthy controls. Significantly elevated levels of FBS, HbA1C and TSH were observed whereas the levels of fT3, fT4 were found to be low in patients when compared to controls. Subclinical hypothyroidism (SCH) in diabetics (both controlled and uncontrolled) was more prevalent (15%) than it was found in healthy controls (5%). Similarly, overt hypothyroidism was also found to be high in diabetic patients (6%) as compared to healthy controls (2%). Significant difference (p <0.05) in the levels of TSH was found between group I (Controlled T2DM) and II (uncontrolled T2DM patients), also between groups II and III (Controls). Group II patients were found to have significant low levels of fT3 as compared to other two groups (Group I and III) (p<0.005).Conclusions: As SCH is more frequent in T2DM diabetes mellitus and untreated SCH patients have higher rate of complications, periodical screening is advised for thyroid dysfunction to prevent micro vascular and cardiovascular complications

Maize in Nepal: Production Systems, Constraints, and Priorities for Research

Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,

Temporal and spatial variations in TEC using simultaneous measurements from the Indian GPS network of receivers during the low solar activity period of 2004?2005

International audienceWith the recent increase in the satellite-based navigation applications, the ionospheric total electron content (TEC) and the L-band scintillation measurements have gained significant importance. In this paper we present the temporal and spatial variations in TEC derived from the simultaneous and continuous measurements made, for the first time, using the Indian GPS network of 18 receivers located from the equator to the northern crest of the equatorial ionization anomaly (EIA) region and beyond, covering a geomagnetic latitude range of 1° S to 24° N, using a 16-month period of data for the low sunspot activity (LSSA) years of March 2004 to June 2005. The diurnal variation in TEC at the EIA region shows its steep increase and reaches its maximum value between 13:00 and 16:00 LT, while at the equator the peak is broad and occurs around 16:00 LT. A short-lived day minimum occurs between 05:00 to 06:00 LT at all the stations from the equator to the EIA crest region. Beyond the crest region the day maximum values decrease with the increase in latitude, while the day minimum in TEC is flat during most of the nighttime hours, i.e. from 22:00 to 06:00 LT, a feature similar to that observed in the mid-latitudes. Further, the diurnal variation in TEC show a minimum to maximum variation of about 5 to 50 TEC units, respectively, at the equator and about 5 to 90 TEC units at the EIA crest region, which correspond to range delay variations of about 1 to 8 m at the equator to about 1 to 15 m at the crest region, at the GPS L1 frequency of 1.575 GHz. The day-to-day variability is also significant at all the stations, particularly during the daytime hours, with maximum variations at the EIA crest regions. Further, similar variations are also noticed in the corresponding equatorial electrojet (EEJ) strength, which is known to be one of the major contributors for the observed day-to-day variability in TEC. The seasonal variation in TEC maximizes during the equinox months followed by winter and is minimum during the summer months, a feature similar to that observed in the integrated equatorial electrojet (IEEJ) strength for the corresponding seasons. In the Indian sector, the EIA crest is found to occur in the latitude zone of 15° to 25° N geographic latitudes (5° to 15° N geomagnetic latitudes). The EIA also maximizes during equinoxes followed by winter and is not significant in the summer months in the LSSA period, 2004?2005. These studies also reveal that both the location of the EIA crest and its peak value in TEC are linearly related to the IEEJ strength and increase with the increase in IEEJ