Ultrasound Speed Research Articles

Continuous and pulsed ultrasound pectin extraction from navel orange peels

Pectin is a valuable product (up to 30 $kg−1) that makes-up 20–30% of an orange’s peel. The commercial extraction is lengthy (up to 6h) and energy intensive as it requires heating aqueous solutions (60–100 °C). Ultrasound speeds up the extraction process reducing processing time by macroscopic and microscopic mixing by acoustic cavitation. We adopted an ultrasonic horn to deliver a rated power of 500W at amplitudes of 20%, 40%, and 60% with and without pulsation to extract pectin from waste orange peels. These correspond to power densities of 0.08Wml−1, 0.16Wml−1 and 0.24Wml−1, respectively. The extractions operated at a pH of either 2 or 3. The experimental data agree with the fitted values from the statistical model (R2=95.5%). The model confirms our predictions that yield increases with amplitude/power density and decreasing pH. The highest yield was (11%) at a pH of 2 and with continuous ultrasonic irradiation at a power density of 0.24Wml−1. There is only a 1.3% difference between this datum and pulse ultrasound mode (1 s on/1 s off) at the same conditions — a Student’s t test confirmed that there was no significant difference in yield between continuous and pulse mode. However, pulsing is more efficient in that it consumes less than half the energy of continuous operation (80kJ vs. 190kJ).

Dietary tryptophan and bone health: a cross-sectional, population-based study.

Tryptophan metabolites, such as serotonin, influence bone. We sought to determine the relationship between dietary intake of tryptophan and bone health in a population-based study of men and women. Participants (1033 women and 900 men, aged 20-98years) enrolled in the Geelong Osteoporosis Study (GOS) were investigated. Dietary information was collected using a validated questionnaire. Tryptophan levels were calculated (mg/day) in accordance with Food Standards Australia and New Zealand and dichotomised according to the median. Bone mineral density (BMD; g/cm2) was measured at the spine (postero-anterior projection) and total hip using dual-energy X-ray absorptiometry. Stiffness index (SI), broadband ultrasound attenuation (BUA) and speed of sound (SOS) were derived from quantitative heel ultrasound. Linear regression models were used to test associations between dietary tryptophan and bone health, after adjustment for potential confounders. Tryptophan intakes ranged from 112 to 3796mg/day (median 1035) in men and 115-2869mg/day (median 885) in women. In men older than 45years and women, a high tryptophan intake was associated with greater hip BMD compared to participants with a low tryptophan intake (p = 0.002 and p = 0.04, respectively); however, these relationships were attenuated by age (all p > 0.05). Participants with high tryptophan intake had greater BUA and SI compared to participants with low tryptophan intake (men; BUA, p = 0.02 and SI, p = 0.02, and women; BUA, p = 0.03 and SI, p = 0.08), yet also attenuated by age (all p > 0.05). No association was found between tryptophan intake and bone health in this population, which suggests a non-critical role of superfluous tryptophan consumption on the skeleton.

Conventional ultrasound characteristics, TI-RADS category and shear wave speed measurement between follicular adenoma and follicular thyroid carcinoma.

The purpose of the study was to explore the differences of conventional ultrasound characteristics, thyroid imaging reporting and data system (TI-RADS) category and shear wave speed (SWS) measurement between follicular adenoma (FA) and follicular thyroid carcinoma (FTC). Twenty-eight FTCs and 67 FAs proven by surgery were retrospectively included for analysis. Conventional ultrasound and point-shear wave elastography (p-SWE) were performed in all of the included patients. The ultrasound features, American Thyroid Association (ATA) TI-RADS category and American College of Radiology (ACR) TI-RADS category, SWS measurement were compared between the two groups. Receiver operating characteristic (ROC) curve was performed and area under ROC curve (AUC) was obtained for significant features. There were no statistical differences in mean age (46.9±15.7years vs. 48.6±13.6years, P = 0.639), gender (9 males, 32.1% vs. 18 males, 29.0%, P = 0.766) and mean diameter (28.3±16.2 mm vs. 33.8±11.9 mm, P = 0.077) between FTCs and FAs. Hypoechogenicity, lobulated or irregular margin, macrocalcification were more common in FTCs than FAs (all P < 0.05). Mean SWS of FTCs (2.29±0.64 m/s) was slightly higher than that of FAs (1.94±0.68 m/s) (P = 0.023). The AUCs were 0.655, 0.744, and 0.744 with the cut-off SWS≥1.89 m/s, ACR TI-RADS category 4 and intermediate suspicion of ATA TI-RADS category. The sensitivity and AUC were 82.1% and 0.812 with combined ultrasound features of hypoechogenicity, lobulated or irregular margin and macrocalcification. In Conclusion, SWS measurement and TI-RADS categories were useful for the identification of FTCs from FAs.

Impact of ultrasound speed choice on the quality of the second-trimester fetal ultrasound examination in obese women

PurposeThe purpose of this study was to assess the impact of the free choice of ultrasound propagation velocity on ultrasound image construction to improve the completion rate and anatomical quality of fetal second-trimester ultrasound examination in obese women. Materials and methodsThis repeated cross-sectional single-center study retrospectively collected second-trimester ultrasound images of 88 obese women. During the first period, ultrasound examinations were performed in 44 women (mean age, 31.4±5.9 [SD] years; range: 21.1 - 45.3 years) applying only the standard 1540m/s tissue ultrasound velocity (group 1). During the second period, ultrasound examinations were performed in other 44 women (mean age, 31.4±5.1 [SD] years; range: 20.6 - 41.6 years) with the operator free to choose among three available velocity settings (1420m/s, 1480m/s or 1540m/s) for the scanning planes for the morphological images (group 2). All women underwent mid-trimester ultrasound examination at 20 to 24 gestational weeks. Two observers assessed the examinations in both groups for completeness, quality, and duration of fetal ultrasound examinations. ResultsNo differences in age (P>0.99), body mass index (P=0.67), prevalence of previous cesarean delivery (P=0.30) or gestational age at the second-trimester scan (P=0.20) were found between the two groups. The mean cumulative duration of these ultrasound examinations was longer in group 1 than in group 2 (for both the complete (P=0.04) and incomplete (P=0.03) examinations). The quality of the anatomic images according to Salomon's criteria was less often acceptable in group 1 (5/44, 11.4%) than in group 2 (15/44, 34.1%) (P=0.02). ConclusionFree choice of ultrasound velocity improves the overall performance of fetal second-trimester ultrasound examinations in obese women.

Ultrasound speed in red deer antlers: a non–invasive correlate of density and a potential index of relative qualit

Deer antlers can be used as an index of individual performance both in ecological and productive contexts. Their quality is often measured only by their biometrical features, such as size, asymmetry or weight. Mechanic characteristics cannot normally be measured without destroying the antler and hence losing the commercial value of the trophies. Here, we studied ultrasonic velocities, density, and tensile strength across various sections of cast antlers of Iberian red deer (Cervus elaphus hispanicus). We found that the speed value depended on the section of the antler and the propagation direction. For antler sections, velocities were lowest for mid–beam and highest for brow tine. Results were similar for density and indirect tensile strength, probably related to differences in functionality among antler sections. Density explained most of the variability of ultrasound–speed. The time elapsed from antler shed affected density more than ultrasound speed. The indirect tensile strength showed a non–linear, decelerating relationship with ultrasound speed. We discuss the applications of ultrasound speed as a non–invasive tool to measure density and physical properties of antlers and antler sections, and their potential use as an index of quality.

Development of a polygenic risk score to improve screening for fracture risk: A genetic risk prediction study.

Since screening programs identify only a small proportion of the population as eligible for an intervention, genomic prediction of heritable risk factors could decrease the number needing to be screened by removing individuals at low genetic risk. We therefore tested whether a polygenic risk score for heel quantitative ultrasound speed of sound (SOS)-a heritable risk factor for osteoporotic fracture-can identify low-risk individuals who can safely be excluded from a fracture risk screening program. A polygenic risk score for SOS was trained and selected in 2 separate subsets of UK Biobank (comprising 341,449 and 5,335 individuals). The top-performing prediction model was termed "gSOS", and its utility in fracture risk screening was tested in 5 validation cohorts using the National Osteoporosis Guideline Group clinical guidelines (N = 10,522 eligible participants). All individuals were genome-wide genotyped and had measured fracture risk factors. Across the 5 cohorts, the average age ranged from 57 to 75 years, and 54% of studied individuals were women. The main outcomes were the sensitivity and specificity to correctly identify individuals requiring treatment with and without genetic prescreening. The reference standard was a bone mineral density (BMD)-based Fracture Risk Assessment Tool (FRAX) score. The secondary outcomes were the proportions of the screened population requiring clinical-risk-factor-based FRAX (CRF-FRAX) screening and BMD-based FRAX (BMD-FRAX) screening. gSOS was strongly correlated with measured SOS (r2 = 23.2%, 95% CI 22.7% to 23.7%). Without genetic prescreening, guideline recommendations achieved a sensitivity and specificity for correct treatment assignment of 99.6% and 97.1%, respectively, in the validation cohorts. However, 81% of the population required CRF-FRAX tests, and 37% required BMD-FRAX tests to achieve this accuracy. Using gSOS in prescreening and limiting further assessment to those with a low gSOS resulted in small changes to the sensitivity and specificity (93.4% and 98.5%, respectively), but the proportions of individuals requiring CRF-FRAX tests and BMD-FRAX tests were reduced by 37% and 41%, respectively. Study limitations include a reliance on cohorts of predominantly European ethnicity and use of a proxy of fracture risk. Our results suggest that the use of a polygenic risk score in fracture risk screening could decrease the number of individuals requiring screening tests, including BMD measurement, while maintaining a high sensitivity and specificity to identify individuals who should be recommended an intervention.

Detecting muscle activation using ultrasound speed of sound inversion with deep learning.

Functional muscle imaging is essential for diagnostics of a multitude of musculoskeletal afflictions such as degenerative muscle diseases, muscle injuries, muscle atrophy, and neurological related issues such as spasticity. However, there is currently no solution, imaging or otherwise, capable of providing a map of active muscles over a large field of view in dynamic scenarios.In this work, we look at the feasibility of applying longitudinal sound speed measurements to the task of dynamic muscle imaging of contraction or activation. We perform the assessment using a deep learning network applied to prebeamformed ultrasound channel data for sound speed inversion.Preliminary results show that dynamic muscle contraction can be detected in the calf and that this contraction can be positively assigned to the operating muscles. Potential frame rates in the hundreds to thousands of frames per second are necessary to accomplish this.

Thermodynamics of molecular interaction of ternary mixture containing ethanol, n-heptane and n-octane at 298.15, 308.15 and 318.15 K

In this research article, densities (ρ), speeds of sound (u) and refractive indices (n) of the ternary liquid mixture of oxygenated fuel additive (ethanol) and aliphatic hydrocarbons (C7, C8) were experimentally measured at different temperatures (T = 298.15 K to 318.15 K) and pressure of 0.1 MPa over whole composition range. Excess molar volume (VmE), excess ultrasound speed (uE), excess isentropic compressibility (ksE), excess intermolecular free length (LfE), excess available volume (VaE) and deviation in refractive index (Δn) of the ternary mixture were evaluated using experimental data. The VmE values were fitted to the Singh, Nagata and Cibulka equations and also interpreted using Prigogine-Flory-Patterson (PFP) theory. Various geometrical solution models like Tsao-Smith model, Kohler model, Rastogi model, Jacob-Fitzner model, and Radojkovic model were used to predict VmE values. The uE, ksE, LfE, VaE and Δn values were also fitted to the Singh equation. Various correlations and mixing rules were used for theoretical prediction of u and n values. Temperature effects on various thermodynamic properties were also studied. The values of VmE, uE, ksE, LfE, VaE and Δn were interpreted in terms of molecular interactions in between the fuel additive and hydrocarbons.

Comparison of the performance of a novel nanolime doped with ZnO quantum dots with common consolidants for historical carbonate stone buildings

Decohesion of building materials caused by weathering translates into the need for recurrent interventions with consolidating treatments that often turn out useless for desired long-term consolidation owing to their poor in-depth penetration. Due to this, it is important to develop new products that allow evaluating their penetration in situ. In this work, three commercial consolidants (Estel 1200®, NanoEstel® and Nanorestore®) widely used in stone conservation were compared with a new consolidant nanocomposite (Nanorepair UV). This nanocomposite, which consists of calcium hydroxide nanoparticles doped with zinc oxide quantum dots, allows both consolidation and in situ evaluation of the penetration depth of the treatment, a key variable to assess effectiveness when an in-depth consolidation is required. The treatments were assayed on limestones from two quarries widely used in the construction of monuments in southern Spain.The development of new products devoted to our Cultural Heritage entails specific requirements such as effectiveness, durability and compatibility with the original materials without changing their aesthetic features. The compatibility was studied by colorimetric methods and SEM images to detect the formation of surface layers. The effectiveness of the treatments was quantified by both peeling test and ultrasound propagation speed. Finally, the durability was studied by an accelerated weathering test induced by salt crystallization.The results showed that nanolimes had higher effectiveness and better durability than silica treatments as consolidants for limestones. In addition, Nanorepair UV provided an additional functionality since it allowed measuring the treatment penetration depth in a simple and economical way, by means of ultraviolet illumination, while allowed to distinguish treated areas from untreated ones.

ANALYSIS OF STRUCTURAL STATES HARDENING BINDER BY CONTINUITY OF THE EXPERIMENTAL CURVE

The development of the building industry inUkrainerequires continuous improvement of building technologies, materials and products. Highly filled gypsum-based heat and sound insulating composites are quite promising. For fast hardening materials on gypsum binders, an important characteristic is the setting time, the knowledge of which is extremely important in the practice of using molding and plaster mixtures, as well as in the technology of bulk floors. Determining the timing of setting compositions of complex structure with the standard Vikat method becomes impossible - large particles block the immersed indenter. In such cases, a property closely related to hardening – plastic strength, electrical conductivity, temperature can be used to determine the setting time. The dependences observed during their measurement are smooth, continuous, and it is impossible to directly determine the setting time from them. The paper proposes a technique for extracting hidden information from experimental data, based on the coordinate transformation procedure. As an example, to implement the proposed methodology, data on plastic strength are used. Using the normalization of experimental data and the transition to re-logarithmic coordinates, the hardening period is divided into the main phases, characterized by the constancy of the conditions of structure formation. They are separated from each other by transitional stages, the onset of which approximately corresponds to the setting time measured by the normative method. The proposed experimental data processing algorithm is quite universal and makes it possible to identify structural formation phases and transitional stages corresponding to setting time also based on data on other properties, for example, electrical conductivity and ultrasound speed. This allows you to effectively use this technique to control the processes of structure formation of highly filled composite mixtures.

A study of the incidence of hip fractures in post-menopausal patients undergoing hemodialysis using quantitative ultrasound, digital image processing and the fracture risk assessment tool

To investigate whether a combination of readily available osteoporosis screening systems, instead of dual energy X-ray absorptiometry (DXA), can aid in the identification of characteristic features of hip fracture in post-menopausal patients undergoing hemodialysis. Forty patients (58-90 years old) who had undergone quantitative ultrasound (QUS) on more than one occasion were included. Heel QUS (conducted yearly for 3 years), digital image processing (DIP), and the fracture risk assessment tool (FRAXR) were used to evaluate bone fragility. The latter two assessments (DIP and FRAXR) were conducted on 25 and 26 of the 40 patients mentioned above respectively, for this study. Hip fractures were identified in five patients. The mean values of broadband ultrasound attenuation (BUA) and speed of sound (SOS) in patients with hip fractures were 80±7 dB/MHz and 1,491±14 m/s, respectively, while the recorded values in patients without fractures were 88±9 dB/MHz and 1,506±22 m/s, respectively. The maximum value of BUA and SOS in patients with hip fractures were 91 dB/MHz and 1,510 m/s, respectively. These values were similar to the mean values in patients without fractures. The DIP (YAM) was 55-67% in four patients with fractures, compared to 44 - 91% in 25 examined patients without fractures. Moreover, in four patients with fractures, the FRAXR score was 12 - 55% for major osteoporotic fracture (MOF) and 3.3 - 9.3% for hip fracture (HF), compared to 4.4 - 33% for MOF and 0.3 -18% for HF in 26 examined patients without fractures. The results of these three methods were not statistically significant between patients with and without fractures. The combination of the three screening systems was not superior diagnostic method for hip fractures in post-menopausal patients, compared to DXA. Heel QUS and FRAXR (MOF, HF), both of which do not include bone mineral content (BMC) and DIP (peripheral cortical bone), which accounts for BMC, were used to evaluate bone fragility. In patients undergoing hemodialysis, the clinical importance of measuring DXA is growing, but it is necessary to estimate not only bone mass, but also bone quality. New modalities for the evaluation of bone quality are required in the future.

Módulo dinámico longitudinal determinado por ultrasonido en madera de tres angiospermas sólida y laminada

&lt;p&gt;&lt;strong&gt;Objetivo: &lt;/strong&gt;determinar el módulo dinámico por ultrasonido en especímenes de madera de &lt;em&gt;Enterolobium cyclocarpum&lt;/em&gt;, &lt;em&gt;Tabebuia rosea&lt;/em&gt; y &lt;em&gt;Juglans pyriformis&lt;/em&gt;.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Método: &lt;/strong&gt;se prepararon 35 probetas de madera sólida y 35 de madera laminada, con el fin de determinar su contenido de humedad, las densidades aparentes, las velocidades del ultrasonido y los módulos dinámicos.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Resultados: &lt;/strong&gt;las magnitudes son diferentes entre los dos tipos de probetas. Tanto para la madera sólida como la laminada de &lt;em&gt;E. cyclocarpum&lt;/em&gt;. &lt;em&gt;T. rosea&lt;/em&gt; y &lt;em&gt;J. pyriformis&lt;/em&gt;, las densidades aparentes se incrementan, pero las velocidades del ultrasonido disminuyen.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Limitaciones: &lt;/strong&gt;los resultados se circunscriben al caso de estudio para las maderas de &lt;em&gt;E. cyclocarpum&lt;/em&gt;, &lt;em&gt;T. rosea&lt;/em&gt; y &lt;em&gt;J. pyriformis&lt;/em&gt;. Las conclusiones se refieren a las condiciones experimentales detalladas en esta investigación.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Principales hallazgos: &lt;/strong&gt;los módulos dinámicos de la madera laminada se incrementan en comparación con los parámetros de la madera sólida de &lt;em&gt;E. cyclocarpum&lt;/em&gt; y &lt;em&gt;T. rosea&lt;/em&gt;, pero disminuyen para &lt;em&gt;J. pyriformis&lt;/em&gt;.&lt;/p&gt;

Structure and Physicochemical Properties of Acetonitrile–o-Dichlorobenzene Solutions

Based on an analysis of concentration dependences of the degree of depolarization and molecular light scattering coefficients, density, ultrasound speed, adiabatic compressibility, excess molar volume and adiabatic compressibility in acetonitrile–о-dichlorobenzene solutions, three ranges with different structures are distinguished: 0–0.2, 0.2–0.9, and 0.9–1.0. Molecular dynamics modeling is performed in each range to obtain a detailed description of the structure of the solutions. It is found that in the first range, the solvation of acetonitrile molecules is accompanied by the local reorientation of о-dichlorobenzene molecules from mainly parallel to mainly perpendicular arrangement. The acetonitrile molecules fall into less dense regions of the о-dichlorobenzene structure and are incorporated into the system of its nonvalent contacts. The second range is the region of the maximum heterogeneity of the solutions, in which an important role is played by both homo- and heteromolecular interactions, and there are agglomerates and conglomerates of the molecules of both components. In the third range, о-dichlorobenzene molecules are solvated, and the mechanism differs from that of the solvation of acetonitrile: о-dichlorobenzene weakly affects the acetonitrile structure and its structure remains virtually unchanged.

Monitoring automobile fuel adulteration using ultrasound technique for environmental issues

Fuel adulteration is a worldwide illegal practice associated with environmental pollution, engine performance degradation and government tax loss, while remaining difficult to control. With the aim of monitoring fuel quality at distribution points, a quick, simple and affordable measurement method based on ultrasound pulsed backscattering was tested towards fuel adulteration. Adulteration tests were carried out using Moroccan commercial gasoline blended with different proportions of diesel and kerosene at different temperatures. The results indicate the possibility of measuring the level of adulterant depending on the value of ultrasound speed, density and acoustic impedance, but were dependent on sample temperature. Nevertheless, subjecting the measured data to principal component analysis enabled detecting the presence and the level of kerosene and diesel in gasoline even at concentrations as low as 4.5% v/v, regardless of ambient temperature, which is especially important when conducting a routine check of fuel quality in real outdoor conditions.

Measurement of Bone Density Parameters using Ultrasound and Hardware Development on bone Density Measurement

Ultrasound waves due to their inherent small wave- length can be used in diagnosis or evaluation of tissue. Ultrasound simulations can be useful to investigate and analyze different properties at different sites especially when there is no volumetric data available. In the proposed paper, simulation of ultrasound in a 2-D bone model and hardware implementation has been presented. Due to complex structures of bone, a simple linear model consisting of both cortical and cancellous bone has been proposed. In the simulation, a broadband emitter with center frequency of 1 Megahertz is used along with an array of receivers to capture the signal. An attempt has been made to calculate bone density parameters in-vivo for human feet, and finally display the computed parameters onto a LCD using Arduino Uno Board. An algorithm involving fourier transforms was used to calculate Broadband Ultrasound Attenuation (BUA) and Speed of Sound (SoS) in Matrix Laboratory (MATLAB).

Effect of Expanded Perlite Aggregate Size on Physical and Mechanical Properties of Ultra Lightweight Concrete Produced with Expanded Perlite Aggregate

In this study, ultra-light weight concrete (ULWC) with heat-insulating properties is produced by using different size expanded perlite aggregates and various admixtures. The compressive strength, 4 point bending strength, freezing and thawing resistance, water absorption, dry unit weight, ultra sound velocities and thermal conductivity of the samples were determined by applying appropriate tests. The effect of different size expanded perlite aggregate on the properties of ULWC were also investigated in this study and it was found that as the expanded perlite aggregate diameter increased, the void volume uniformity, water absorption percentage and freezing-thawing resistance increased while the unit volume weight of ULWC samples, ultrasound speed velocities, thermal conductivity and compressive strength were decreased. The changes in the masses and compressive strength of ULWC samples subjected to freezing and thawing cycles were examined. The compressive strength loss was found to be between 5 % and 47 % while the weight loss was between 1 % and 3.5 % after 15 freezing and thawing cycles. Finally, the effects of the admixtures on the fresh properties of ULWC were examined and it was determined that the use of 4.5 kg of air-entraining material in one cubic meter of concrete mix is the most ideal ratio and the use of more than 0.01 % by volume of polypropylene fiber is caused settlements in fresh concrete mixtures.

Use of Time-of-Flight Ultrasound to Measure Wave Speed in Poplar Seedlings

In this study, 145 poplar (Populus × euramericana cv.’74/76’) seedlings, a common plantation tree species in China, were selected and their ultrasonic velocities were measured at four timepoints during the first growth year. After that, 60 poplar seedlings were randomly selected and cut down to determine their acoustic velocity, using the acoustic resonance method. The effects of influencing factors such as wood green density, microfibril angle, growth days, and root-collar diameter on acoustic speed in seedlings and the relationship between ultrasonic speed and acoustic resonance speed were investigated and analyzed in this work. The number of specimens used for investigating growth days and root-collar diameter was 145 in both cases, while 60 and two specimens were used for investigating wood density and the microfibril angle, respectively. The results of this study showed that the ultrasonic speed of poplar seedlings significantly and linearly increased with growth days, within 209 growing days. The ultrasonic velocity of poplar seedlings has a high and positive correlation with growth days, and the correlation was 0.99. However, no significant relationship was found between the ultrasonic velocity and root-collar diameter of poplar seedlings. Furthermore, a low and negative relationship was found between wood density and ultrasonic speed (R2 = 0.26). However, ultrasonic velocity significantly decreased with increasing microfibril angle (MFA) in two seedlings, and thus MFA may have an impact on ultrasonic speed in poplar seedlings. In addition, ultrasonic velocity was found to have a strong correlation with acoustic resonance velocity (R2 = 0.81) and a good correlation, R2 = 0.75, was also found between the dynamic moduli of elasticity from ultrasonic and acoustic resonance tests. The results of this study indicate that the ultrasonic technique can possibly be used to measure the ultrasound speed of young seedlings, and thus early screen seedlings for their stiffness properties in the future.

Observation of ultrasonic signal and measurement of H2 concentration from the exterior of a metal pipe

Concentration of H2 gas in a stainless steel (SUS) pipe is measured by using ultrasound from the exterior of a pipe without making a hole. Gas concentration is calculated by the variation of ultrasound speed detected. A sound absorbing material is put on the outer surface of the SUS pipe to reduce the ultrasonic signal noise circulating through the shell of the SUS pipe. Then it is possible to measure the gas concentration by observing the airborne signal passing through the SUS pipe. Propagation of ultrasound wave in SUS pipe is also simulated by the finite-difference-time-domain method that could explain the ultrasound propagation signals in the SUS pipe.

Bone Analysis in the Newborn - Quantitative Ultrasound of the Peripheral Skeleton

The aim was to determine whether the quantitative ultrasound (QUS) parameter speed of sound (SOS) is sufficient for evaluation of reference data in the newborn and how they are influenced. 219 full-term and 14 preterm infants (gestational age 28-41 weeks (GA), birth weight 590-4,930 g) were evaluated by Omnisense 7000 P on their tibia. Reference values were sampled in 178 eutrophic infants. SOS reference values at the tibia were 3028 m/s for GA<40 and 3057 m/s for ≥ 40 weeks. There was a significant correlation between SOS and gestational age. SOS was significantly higher in male (3058.3±93.3 vs. 3022.8±93.4 m/s; p 0.012) infants. If birth weight was below 3,800 g, there was a correlation between SOS and weight (p<0.05). Preterm infants showed lower SOS than term babies (p<0.05). Speed of sound can be evaluated sufficiently in preterm and term infants on the tibia. The estimated reference data can be used to identify osteopenia in the preterm infant with low birth weight.

Physico-mechanical characterization of the limestone used in Cartagena walls and a proposal for their restoration process

The defensive walls of Cartagena de Indias, UNESCO cultural heritage since 1984, surround the historic centre of the Colombian City. Nowadays, the walled city represents the main tourist attraction of the Colombian Caribbean Sea and is also a world destination. Despite this importance, due to anthropogenic and environmental factors, the walĺs structure is highly deteriorated, with widely damaged sections at distinct risk of collapse, where replacement of deteriorated stone blocks is carried out without a technical criterion. The main purpose of this paper was to determine some criteria for selecting the most appropriate limestone to be used in the restoration process, based on empirical relations among ultrasound wave speed, mechanical strength, porosity, bulk density and elastic modulus of different limestones taken from five quarries located around the city. Analyzed physical properties showed that the current wall’s stone open porosity ranges between 18% and 25%, while the quarry stone range is between 7% and 44%. As for the quarry stone, the uniaxial compressive strength (UCS) variation varied from 1.88 MPa to 21 MPa. Results showed that in order to select the best stone to be used as a replacement, samples should have an ultrasound P-wave speed between 3844 and 4195 ms−1, and a dry mass between 223 and 251 g in a 5 cm cubic sample. A valid tool is proposed to the relevant authorities in the subject-matter to identify the right range of porosity and mass of the quarry stone to be employed in substitution of the deteriorated wall blocks, thus facilitating the restoration practices.