scholarly journals New Results from Strapdown Airborne Gravimetry Using Temperature Stabilisation

2019 ◽  
Vol 11 (22) ◽  
pp. 2682 ◽  
Author(s):  
Tim E. Jensen ◽  
Arne V. Olesen ◽  
Rene Forsberg ◽  
Per-Anders Olsson ◽  
Örjan Josefsson

In recent years, the use of a strapdown Inertial Measurement Unit (IMU) for airborne gravimetry has proven itself to be an accurate and resilient measurement system, improving the operational flexibility. The main concern is erroneous long-wavelength information in the resulting estimates, which is suspected to originate from uncompensated long-term drift of the accelerometers, probably originating from temperature variation. For this reason, iMAR navigation has designed a temperature stabilisation box, which allows for temperature stabilisation of their IMU systems. On a regional airborne gravity survey over the Kattegat Sea between Denmark and Sweden, such a temperature stabilised strapdown IMU was operated alongside a traditional spring-type platform-stabilised gravity system from ZLS. An analysis of the difference in gravity estimates at cross-over locations yielded a mean value of −0.3 mGal for the iMAR system with an indicated accuracy of 1.0 mGal. The temperature stabilisation unit therefore effectively limits the accelerometer drift and improves the long-wavelength information. However, a straightforward merging approach, adjusting the line-based mean values of the iMAR estimates to match that of the ZLS estimates, improved the accuracy to 0.8 mGal. This indicates that the long-wavelength information of the stabilised-platform system is still superior to that of the strapdown system.

2004 ◽  
Vol 35 (2) ◽  
pp. 119-137 ◽  
Author(s):  
S.D. Gurney ◽  
D.S.L. Lawrence

Seasonal variations in the stable isotopic composition of snow and meltwater were investigated in a sub-arctic, mountainous, but non-glacial, catchment at Okstindan in northern Norway based on analyses of δ18O and δD. Samples were collected during four field periods (August 1998; April 1999; June 1999 and August 1999) at three sites lying on an altitudinal transect (740–970 m a.s.l.). Snowpack data display an increase in the mean values of δ18O (increasing from a mean value of −13.51 to −11.49‰ between April and August), as well as a decrease in variability through the melt period. Comparison with a regional meteoric water line indicates that the slope of the δ18O–δD line for the snowpacks decreases over the same period, dropping from 7.49 to approximately 6.2.This change points to the role of evaporation in snowpack ablation and is confirmed by the vertical profile of deuterium excess. Snowpack seepage data, although limited, also suggest reduced values of δD, as might be associated with local evaporation during meltwater generation. In general, meltwaters were depleted in δ18O relative to the source snowpack at the peak of the melt (June), but later in the year (August) the difference between the two was not statistically significant. The diurnal pattern of isotopic composition indicates that the most depleted meltwaters coincide with the peak in temperature and, hence, meltwater production.


2017 ◽  
Vol 11 (1) ◽  
pp. 1041-1048 ◽  
Author(s):  
Mehmet Bekir Unal ◽  
Kemal Gokkus ◽  
Evrim Sirin ◽  
Eren Cansü

Objective: The main objective of this study is to evaluate the availability of lateral antebrachial cutaneous nerve (LACN) autograft for acute or delayed repair of segmented digital nerve injuries. Patients and Methods: 13 digital nerve defects of 11 patients; treated with interposition of LACN graft that harvested from ipsilateral extremity were included in the study. Mean follow up period was 35, 7 months. The mean time from injury to grafting is 53, 3 days. The results of the mean 2PDT and SWMT values of injured /uninjured finger at the end of follow up period were evaluated with Paired T test. The correlation between the defect length and the difference of 2PDT, SWMT values between the uninjured and injured finger at the end of follow up period; were evaluated with Pearson - correlation analysis. Results: The mean value of our 2PDT and SWMT results are ~5,923, ~3, 52, respectively in which can be interpreted between the normal and diminished light touch. The defect length and difference percentage of SWMT values is positively and significantly correlated statistically. Mean length of interposed nerve grafts was 18.5 mm. The age of the patient and the mean values of 2PDT and SWMT with the difference % of 2PDT and % of SWMT are not statistically correlated. Conclusion: Based on results regarding sensory regaining at recipient side and negligible sensory deficit at harvesting side, we suggest that lateral antebrachial cutaneous nerve might be a valuable graft option for digital nerve defects.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3993-3993
Author(s):  
Fotis F.I. Girtovitis ◽  
Dimitrios D. Bougiouklis ◽  
Michel M.P. Makris ◽  
Elefteria E. Pithara ◽  
Pantelis P.E. Makris

Abstract Aim: We decide to study the effect of erythropoietin on the platelet function and glycoproteins expression in patients (pts) with myelodysplastic syndrome (MDS). All patients suffered from primary MDS but none of them received any special treatment. From our study pts that suffered from diseases or they were receiving medication that affect the function of platelets were excluded. Furthermore pts with platelet count<50,000/μl were excluded also because we were unable to check the aggregation of platelets. Material: 41 subjects were studied, 15 normal subject (10 men and 5 women mean age 66,6±14 years old)and 26 pts (17 men and 9 women with mean age70,9±7,4 years old) suffered from all types of MDS according to FAB criteria (9 with RA, 3 with RARS, 7 RAEB, 4 with CMML and 3 with RAEB-t). We divided them in 2 groups: 1st - 7 Pts receiving human recombinant erythropoietin (rEPO) with mean dose 30.000 iu subcutaneous weekly and 2nd - 19 without rEPO. Methods. 1- The platelet function was studied in Platelet Ionized Calcium Aggregometer (PICA) using Ristocetin, ADP, Collagen and Adrenalin as stimulators. 2- The expression of platelet glycoproteins (GPIb, IX, IIb, IIIa and P-selectin) was studied using the flow cytometry and special monoclonal antibodies. This way the percentage of glycoprotein expressed in platelet membrane and MFI were estimated. We performed the statistical analysis of our results using the t-test with common standard deviation.. Results: our results concerning the aggregation test and flow cytometry are presented in tables 1,2 and 3. From the study of our results we can see that while the decrease of aggregation between the patients under EPO and normal subjects is statistically non significant (p<0.1)the decrease of the corresponding values between the pts that did not received EPO and normal subjects was statistically very significant for all stimulators (p <0,001). pts under EPO show an important increase of platelet expressing GPIIb percentage grater than the expressed percentage of patients without EPO (60% vs. 46,1% correspondingly, p<0.001). The difference of expressed MFI was not statistically significant. Conclusion: The findings of our study show us that erythropoietin improves the function of platelets in patients with MDS, probably through the increase of platelet percentage which express glycoproteins. Table 1 Comparison of the mean value of aggregation between the groups Table 2 Comparison of the mean values of the platelets expressing corresponding glycoproteins percentage between the groups Table 3 Comparison of the mean value of MFI between the groups


2020 ◽  
Author(s):  
Ebaa Ibrahim Alagha

Abstract Aim of the study: This study evaluated the impact of two remineralizing agents containing casein phosphopeptideamorphous calcium phosphate (CPPACP), and Tricalcium phosphate (TCP) on white spot lesions. Materials and Methods: A total of ninety freshly extracted upper premolars were divided in three equal groups (30 each). Group A: Control group. Group B: Varnish containing CPP–ACP. Group C: Varnish containing TCP. The teeth were subjected to Diagnodent test after inducing white spot lesions to assess any surface changes present on the teeth. The readings were repeated post demineralization and post-remineralization. Results: Statistically significant difference was present in the mean values between the tested groups. CPP-ACP group recorded higher mean value at demineralization when compared to TCP group. Statistically significant difference (p < 0.0001) was present between the baseline and the demineralization values. CPP-ACP group presented higher remineralization results when compared to TCP group. T-test proved a significant difference between the tested groups. Conclusion: CPP-ACP containing varnish had higher remineralizing effect when compared to TCP containing varnish. Clinical Significance: Recently, the focus of restorative dentistry has been directed toward a conservative approach. Prevention and non-restorative treatment of initial enamel caries is the main concern. Remineralization procedures are the most preferred way of regeneration of lost tooth structure.


PEDIATRICS ◽  
1964 ◽  
Vol 33 (6) ◽  
pp. 969-974
Author(s):  
Constantine S. Anast

Two hundred and thirty-eight determinations of serum magnesium levels during the first 4 days of life were carried out on 78 infants. No statistically significant differences were found when these values were compared to those determined in 111 older children and adults. Differences in mean values between any of the first 5 days were not statistically significant nor were any significant differences found when the values of each day were compared with the mean value of older children and adults or the mean value of the cord bloods. The mean values on days 3, 4, and 5 were higher in breast-fed infants than in infants fed evaporated milk. Higher values in breast-fed infants and lower values in evaporated-milk-fed infants on days 3 and 4 when compared to day 1 in the same infant were found in a significant number of cases. The possibility that the observed differences in these two groups of infants may be related to the difference in phosphate to magnesium ratio in cow's milk as compared to human milk is discussed. Further investigation of this problem is needed before definite conclusions can be drawn.


2014 ◽  
Vol 1048 ◽  
pp. 567-570
Author(s):  
Jun Wang ◽  
Xiao Jiu Li ◽  
Xiao Mei Chen ◽  
Tong Yao ◽  
Li Pan

This study aims to investigate the anthropometric feature of young women aged between 18 and 25 from Northeastern China, and compare the difference between the young Northeastern China women and the national adult females. More than 400 young Northeastern China women were measured, and the body data were collected by mix-measurement of 3D scanner and manual method, and the main sizes were extracted to descript the total anthropometric characterizes. The high mean value of the Northeastern young women is 162.3 CM, which is 5.75 CM higher than the national adult females. In the high direction, the other mean values of the samples are variously higher than the national adult females. Overall, the young Northeastern China women are taller than the national adult females and well proportioned. In the width direction, the mean values of bust, waist and neck of the 18-25 years old young women are larger than the national adult females, except the hip.


2018 ◽  
Vol 23 (2) ◽  
pp. 68-74 ◽  
Author(s):  
Sergio Luiz Mota Júnior ◽  
Marcio José da Silva Campos ◽  
Carina Abrantes Schmitberger ◽  
Juliana de Andrade Vitral ◽  
Marcelo Reis Fraga ◽  
...  

ABSTRACT Objective: The purposes of this study were to present a prototype of a bracket-positioning gauge, which makes vertical inclination of the instrument difficult, allowing a reduction of vertical bracket positioning error, and to test its accuracy in bracket positioning by groups of individuals with different clinical experience and in specific groups of teeth. Methods: For the testing of the prototype, four groups of six participants each were used: Group 1 was composed of undergraduate students in the dental school, who had no previous experience in bonding orthodontic attachments; Group 2 was composed of orthodontic graduate students in the dental school; Group 3 consisted of orthodontists with a maximum of 5 years of clinical experience; Group 4 comprised orthodontists with more than 5 years of clinical experience. A typodont was simulated with a Class I crowded malocclusion, which reproduced the same occlusal characteristics for all groups to be bonded. All participants were instructed to bond 0.022×0.028-in Edgewise brackets on the labial surfaces of the upper and lower incisors, canines, and premolars at a height of 4 mm from the incisal edge or the labial cusp tip. Results: Only the mean value of Group 1 showed statistically significant difference in the comparison with the standard measurement. In the groups of teeth, the difference was significant for the premolar and incisor groups. Conclusion: Clinical experience interfered with the accuracy of vertical positioning of orthodontic attachments. As for the groups of teeth, premolars, followed by canines and incisors had the closest mean values to the standard measurement.


Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2903
Author(s):  
Magda Joachimiak

This paper presents results of research on unevenness of cylinder heating in a furnace for thermo-chemical treatment. Experimental research was conducted with respect to nitriding. Various heating speeds and settings of the fan operation in the furnace were considered. Boundary conditions were calculated in the form of temperature and the heat transfer coefficient (HTC) on the cylinder boundary in four planes along the cylinder length. Calculations were performed with the use of the inverse problem for non-linear and unsteady heat conduction equations. Boundary conditions from individual planes were compared with the mean value of them all. The variability of the calculated boundary conditions (temperature and HTC) along the cylinder length was investigated based on values of the absolute and relative differences for temperature and HTC. Estimates: mean value, mean value from the absolute value and the maximum values for the absolute and the relative differences of temperature and HTC were also calculated. Estimates were the measurements of the unevenness of cylinder heating in a furnace for thermo-chemical treatment. Based on the results of our research, it was found that an increase of the fan rotational speed from 50% to 100%, with the same heating speed, resulted in a significant leveling of temperature in the analyzed planes. The difference in temperature along the cylinder length was reduced from 6.8 °C to 3.3 °C. The increase of the heating speed from 5 °C/min to 10 °C/min resulted in an increase of the unevenness of the cylinder heating. Values of the absolute differences of temperature in the analyzed planes with reference to the mean temperature changed from an interval from −2.7 °C to 2.3 °C to a range from −4 °C to 5 °C. In processes with a heating speed greater than 5 °C/min, more intensive heating in the end part of the cylinder (close to the cylinder) was achieved than it was in other planes. It was proven by temperature values, which were higher, even, by 5.4 °C, and by HTC values, higher by 11.4 W/m2K, when compared with mean values. Obtained results can form the basis for nitriding process optimization.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Leila Azouaou toualbi ◽  
Medina Arab ◽  
Chahine Toualbi ◽  
Khelfi Abderrezak ◽  
Henni Chader ◽  
...  

Abstract Background and Aims Oxidative stress represents a risk factor for cardiovascular complications . The aim of the work is to evaluate the effectiveness of vitamin E on cardiovascular complications in hemodialysis patients. Method a study including 420 patients on hemodialysis and 360 controls. Treatment with Vit E at a rate of 300 mg / day for 2 years. All patients benefited from a blood sample of oxidative stress markers as well as paraclinical explorations in search of cardiovascular complications. Results The study grouped together 780 cases. We find that there is a significant relationship between cardiovascular complications and Advanced Oxidation Protein Product (AOPP), Low Density Oxidized Lipoprotein (LDLox), Malondialdehydes (MDA) and Gluthations), we did not find any correlation with nitrogen monoxide (NO) and myeloperoxidases (MPO) .Concerning gluthations (IU / ml ) we observe that the mean values clearly increased after treatment (P-value &lt;0.05) . The mean value of MDA µmol / l significantly decreased after treatment .we note that the cardiovascular complications have decreased (11.03% versus 16.04%) with the decrease in certain markers of oxidative stress. (p &gt; 0.05) Conclusion Regarding cardiovascular complications, we have certainly noticed a drop in their frequency after treatment with vit E without the difference being significant.


Geophysics ◽  
1971 ◽  
Vol 36 (5) ◽  
pp. 867-877 ◽  
Author(s):  
Sigmund Hammer

Analysis of components of the gravity anomaly field from basic one, two, and three‐dimensional masses demonstrates that all components of the same derivative order attenuate with flight elevation at the same rate for a given type of anomaly. Different types of anomalies attenuate with significantly different rates. The signal strength of an anomaly component is conveniently defined as the difference between values at adjacent maximum and minimum points along a profile. For a given type of anomaly, the signal strengths of all comparable components are roughly equal, within about half an order of magnitude. Relative attenuations of anticipated signal and terrain noise permit evaluation of favorable and unfavorable prospect areas for airborne gravity exploration. A corollary result is that the tolerance in flight elevation control is orders of magnitude less severe for gradiometer surveying than for airborne gravity surveying. The conclusions are relevant in the choice of the most advantageous component for possible development of airborne gravimetry.


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