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The Demand for circulating cooling water (CCW) with high temperature stability and a quick response to temperature control is essential for precision engineering, so a dynamic thermal filtering method is proposed in this paper. Some CCW is bypassed, blocked, and used as a thermal capacity medium, and the temperature fluctuation of CCW is significantly reduced by heat exchanging with the medium. The temperature of the medium dynamically follows the set value of the CCW temperature by real time updating, and so realizes a quick CCW temperature control response. The attenuation ratio of temperature fluctuation was derived, theoretically validating the effectiveness of the method. The experimental results indicate that a CCW temperature fluctuation attenuation ratio of tens of dB (&minus, 3.47 dB, &minus, 6.91 dB, &minus, 10.97 dB and &minus, 15.28 dB corresponding to temperature fluctuation frequencies of 0.01 Hz, 0.025 Hz, 0.053 Hz and 0.105 Hz, respectively) is achieved by the proposed method. The updating time of thermal capacity medium is 82 s, which means that the temperature fluctuation attenuation remains functionally valid when the set value of CCW changes. The proposed method is low cost in operation and provides an effective approach to satisfy the challenging demand for CCW with high stability and a good dynamic temperature control performance.

Powder flow and temperature distribution are recognized as essential factors in the laser melting deposition (LMD) process, which affect not only the layer formation but also its characteristics. In this study, two mathematical models were developed. Initially, the three-jet powder flow in the Gaussian shape was simulated for the LMD process. Next, the Gaussian powder flow was coaxially added along with the moving laser beam to investigate the effect of powder flow on temperature distribution at the substrate. The powder particles&rsquo, inflight and within melt-pool heating times were controlled to avoid vapors or plasma formation due to excessive heat. Computations were carried out via MATLAB software. A high-speed imaging camera was used to monitor the powder stream distribution, experimentally, while temperature distribution results were compared with finite element simulations and experimental analyses. A close correlation was observed among analytical computation, numerical simulations, and experimental results. An investigation was conducted to investigate the effect of the focal point position on powder stream distribution. It was found that the focal point position plays a key role in determining the shape of the powder stream, such that an increment in the distance from the focus point will gradually transform the powder stream from the Gaussian to Transition, and from the Transition to Annular streams. By raising the powder flow rate, the attenuation ratio prevails in the LMD process, hence, decreasing the laser energy density arriving at the substrate. The computations indicate that, if the particle&rsquo, s heating temperature surpasses the boiling point, a strong possibility exists for vapors and plasma formation. Consequently, an excessive amount of laser energy is absorbed by the produced vapors and plasma, thus impeding the deposition process.

We aimed to test the hypothesis that the spleen-to-liver-attenuation ratio on portal-venous enhancement phase CT images can identify diffuse splenic infiltration in subjects with lymphoma. A database search yielded 70 subjects with malignant haematological diseases who underwent contrast-enhanced CT (CECT) between December 2010 and March 2018. Additionally, consecutive control subjects were evaluated. We compared the splenic volume, splenic attenuation, spleen-to-liver, spleen-to-aorta and spleen-to-musculature ratios on portal-venous phase CECT images, pre- to post-treatment and between the different lymphoma entities. The standard of reference for splenic involvement was normalisation of the spleen volume following chemotherapy or normalisation of FDG-uptake. In subjects with diffuse splenic involvement, the spleen attenuation was significantly lower before treatment (93.48 HU) compared to controls (112.39 HU; p < .01) and after successful treatment (113.39 HU; p < .01). The spleen-to-liver attenuation ratio significantly increased after treatment (p < .001) and proved significantly lower at baseline when compared to control subjects (p < .01). The spleen volume significantly decreased after successful treatment (from 586.14.87 cm3 to 284.90 cm3; p < .001). Spleen-to-liver ratio significantly increased in lymphoma patients after therapy, inversely correlating with the decline in FDG-uptake (n=10) even in patients with normal-sized spleens (2/10), staying unchanged at follow-up. The outcome variables were not significantly different between the lymphoma subtypes. We suggest the additional use of spleen-to-liver attenuation ratio to splenic volume alone for detection of diffuse splenic infiltration in subjects with lymphoma. The course of spleen-to-liver attenuation ratio inversely correlated with that of FDG-uptake in a subgroup of patients working accurately in normal-sized diffusely involved spleens. • Involvement of the spleen is frequent in haematological malignancies and is important for staging and appropriate treatment. • Diffuse splenic infiltration often results in only homogeneous splenomegaly without a focal lesion, but even no or only minimal increase in splenic volume is possible. In these cases diagnosis of spleen involvement is a challenge for the radiologist. • Our data support the use of the spleen-to-liver attenuation ratio in addition to size measurements for the detection of diffuse splenic infiltration in subjects with lymphoma.

To enable a more in-depth understanding of the flash evaporation from the downward jet and extend the research range of spray flash evaporation, a mathematical model based on the diffusion-controlled evaporation model was proposed and developed. The droplet motion, droplet size variation and temperature variation are taken into account in the present model. The model was validated against the experimental data sets from literature sources. The temperature variation against the traveled distance was obtained and analyzed. Four variables, namely, flow velocity, pressure attenuation ratio, droplet size and relative humidity, were investigated by means of this model.

Background The aim of this proof-of-concept study was to show that the liver segmental volume and attenuation ratio (LSVAR) improves the detection of significant liver fibrosis on portal venous CT scans by adding the liver vein to cava attenuation (LVCA) to the liver segmental volume ratio (LSVR). Material and methods Patients who underwent portal venous phase abdominal CT scans and MR elastography (reference standard) within 3 months between 02/2016 and 05/2017 were included. The LSVAR was calculated on portal venous CT scans as LSVR*LVCA, while the LSVR represented the volume ratio between Couinaud segments I-III and IV-VIII, and the LVCA represented the density of the liver veins compared to the density in the vena cava. The LSVAR and LSVR were compared between patients with and without significantly elevated liver stiffness (based on a cutoff value of 3.5 kPa) using the Mann–Whitney U test and ROC curve analysis. Results The LSVR and LSVAR allowed significant differentiation between patients with (n = 19) and without (n = 122) significantly elevated liver stiffness (p Conclusion The LSVAR improves the detection of significant liver fibrosis on portal venous CT scans compared to the LSVR.

Objective: To investigate whether quantitative computed tomography (CT) measurements can predict microvascular invasion (MVI) in hepatocellular carcinoma (HCC). Materials and Methods: This was a retrospective analysis of 200 cases of surgically proven HCCs in 125 consecutive patients evaluated between March 2010 and November 2017. We quantitatively measured regions of interest in lesions and adjacent areas of the liver on unenhanced CT scans, as well as in the arterial, portal venous, and equilibrium phases on contrast-enhanced CT scans. Enhancement profiles were analyzed and compared with histopathological references of MVI. Univariate and multivariate logistic regression analyses were used in order to evaluate CT parameters as potential predictors of MVI. Results: Of the 200 HCCs, 77 (38.5%) showed evidence of MVI on histopathological analysis. There was no statistical difference between HCCs with MVI and those without, in terms of the percentage attenuation ratio in the portal venous phase (114.7 vs. 115.8) and equilibrium phase (126.7 vs. 128.2), as well as in terms of the relative washout ratio, also in the portal venous and equilibrium phases (15.0 vs. 8.2 and 31.4 vs. 26.3, respectively). Conclusion: Quantitative dynamic CT parameters measured in the preoperative period do not appear to correlate with MVI in HCC. Resumo Objetivo: O objetivo deste estudo foi investigar se parâmetros quantitativos da tomografia computadorizada (TC) podem predizer invasão microvascular (IMV) no carcinoma hepatocelular (CHC). Materiais e Métodos: Foram analisados, retrospectivamente, 200 CHCs comprovados de 125 pacientes submetidos consecutivamente a transplante ou ressecção hepática entre março/2010 e novembro/2017. Foram realizadas medidas quantitativas da densidade das lesões e do parênquima hepático adjacente pré-contraste e nas fases arterial, portal e de equilíbrio das TCs. Parâmetros de impregnação foram comparados com a presença de IMV nos laudos anatomopatológicos. Regressões logísticas univariadas e multivariadas foram utilizadas para avaliar os parâmetros da TC como potenciais preditores de IMV. Resultados: Dos 200 CHCs, 77 (38,5%) tinham IMV no anatomopatológico. Não houve diferença estatística na razão de atenuação entre CHCs com IMV e os sem IMV na fase portal (114,7 para IMV positiva e 115,8 para IMV negativa) ou de equilíbrio (126,7 para IMV positiva e 128,2 para IMV negativa), nem na razão de washout relativa nas fases portal e de equilíbrio (15,0 para IMV positiva e 8,2 para IMV negativa na fase portal, e 31,4 para IMV positiva e 26,3 para IMV negativa na fase de equilíbrio). Conclusão: Não houve relação entre os parâmetros quantitativos da TC pré-operatória e IMV dos CHCs.

In this paper, the attenuation ratio of obliquely incident electromagnetic (EM) wave in a plasma with Epstein profile is investigated. Based on the scattering matrix method, the effects of different parameters on the attenuation ratio under oblique incidence angle are analyzed. The numerical results show that EM wave with larger incidence angle is more likely to be absorbed in the plasma. In addition, the attenuation ratio can be changed by adjusting different plasma parameters.

This paper presents the optimal number of sensor and placement in 170 kV $(13.8\ \mathrm{m}\times 3.2\ \mathrm{m}\times 4.8\ \mathrm{m})$ and 362 kV $(15.6\ \mathrm{m}\times 14.5\ \mathrm{m}\times 8.5\ \mathrm{m})$ GIS based on finite difference time domain (FDTD) method. The 5 pC discharge using artificial defect was measured according to international council on large electric systems (CIGRE) TB 654. The experiment environment according to CIGRE was simulated to analyze attenuation of electromagnetic (EM) wave in prototype GIS. The reference attenuation ratio (RAR) to detect 5 pC PD was analyzed depending on the distance between PD source and sensor in prototype GIS using FDTD method. The optimal sensor placement was proposed in 170 kV, 362 kV GIS based on RAR. In addition, the channel characteristics of GIS was analyzed and proposed for the target frequency band of the ultra-high frequency (UHF) sensor.

The potential of dual-energy mammography for microcalcification classification was investigated with simulation and phantom studies. Classification of type I/II calcifications was performed using the tissue attenuation ratio as a performance metric. The simulation and phantom studies were carried out using breast phantoms of 50% fibroglandular and 50% adipose tissue composition and thicknessess ranging from 3 to 6 cm. The phantoms included models of microcalcifications ranging in size between 200 and 900 μ m . The simulation study was carried out with fixed MGD of 1.5 mGy using various low- and high-kVp spectra, aluminum filtration thicknesses, and exposure distribution ratios to predict an optimized imaging protocol for the phantom study. Attenuation ratio values were calculated for microcalcification signals of different types at two different voltage settings. ROC analysis showed that classification performance as indicated by the area under the ROC curve was always greater than 0.95 for 1.5 mGy deposited mean glandular dose. This study provides encouraging first results in classifying malignant and benign microcalcifications based solely on dual-energy mammography images.

Purpose: To investigate the potential of spectral mammography to distinguish between type I microcalcifications, consisting of calcium oxalate dihydrate compounds typically associated with benign lesions, and type II microcalcifications containing hydroxyapatite which are predominantly detected in malignant tumors. Methods: Simulation and phantom studies were carried out using polyenergetic spectra from a tungsten anode x-ray tube at low and high voltage (kVp) settings. Low- and high-energy attenuation ratios were calculated for microcalcifications of different types and thicknesses. Classification of type I or II calcifications was performed by using the attenuation ratio as a criterion. The results were evaluated using receiver operating characteristic (ROC) analysis. Results: In simulation studies, four combinations of dual (low and high kVp) energy exposure technique were investigated: 1) 30 kVp, 1 mm aluminum filtration and 50 kVp, 0.1 mm copper filtration; 2) 30 kVp, 1 mm Al and 50 kVp 0.2 mm Cu; 3) 30 kVp, 2 mm Al and 50 kVp, 0.1 mm Cu; and 4) 30 kVp 2 mm Al and 50 kVp, 0.2 mm Cu. In the ROC curve analysis, area under the curve (AUC) values were above 0.95 for all of the spectra with the exposure equivalent to 1.5 mGy of the mean glandular dose delivered to a 4 cm thick breast phantom. 30 kVp/2 mm Al and 50 kVp/0.1 mm Cu tube voltage/filter combinations demonstrated better performance compared to other combinations. In phantom studies, a 40 kVp setting paired with 1 mm Al filter and a 70 kVp setting paired with 0.1 mm Cu filter operated at 20 mAs technique were used. Obtained AUC value was also high (0.91), supporting the accuracy of the proposed classification method. Conclusion: The results of the current study suggest that dual energy mammography systems have potential to be used for discrimination between type I and type II microcalcifications to improve early breast cancer diagnosis and reduce the number of unnecessary breast biopsies.

Objective: This study aimed to assess and compare the diagnostic performance of the coronary artery to aortic luminal attenuation ratio (CAR), transluminal attenuation gradient (TAG), and corrected coronary opacification (CCO) difference on coronary CT angiography (cCTA) for detecting haemodynamically significant coronary artery stenosis. Methods: 33 patients who underwent cCTA, gated SPECT myocardial perfusion imaging (MPI), and invasive coronary angiography within 3 months were included in this retrospective study. The degree of coronary stenosis on cCTA was visually assessed in all patients. Additionally, CAR, TAG, and CCO difference were analyzed and calculated in all patients. Haemodynamically significant coronary stenosis was defined as a vessel with ≥50% luminal stenosis on invasive coronary angiography and an associated abnormal perfusion defect on MPI in the same territory. Diagnostic performance was assessed on a per-vessel basis by the area under the receiver operating characteristic (ROC) curve (AUC). Results: Among 99 vessels, 12 were excluded and the remaining 87 were analyzed. 17 (19.5%) vessels were determined as haemodynamically significant coronary artery stenosis. On ROC analysis, the AUC was 0.71 for cCTA, 0.80 for CAR, 0.61 for TAG, 0.74 for CCO, 0.87 for combined CAR and cCTA, 0.77 for combined TAG and cCTA, and 0.75 for combined CCO and cCTA. The AUC for combined CAR and cCTA was significantly greater compared with cCTA alone (p < 0.01). Conclusion: Non-invasive CAR derived from 64-detector row CT was feasible and might be helpful for the detection of haemodynamically significant coronary artery stenosis. Still, further investigations such as intra- and inter-reader correlation, evaluation of larger numbers in different settings, and time efficiency are required for applying CAR in various situations. Advances in knowledge: CAR could be used as novel noninvasive technique to detect haemodynamically significant coronary artery stenosis.

Temperature dependences of liquid alloys contain non-monotonic fragments in the form of excesses and breaks. The paper analyzes the dependences of oscillations’ attenuation ratio upon temperature. The qualitative and quantitative estimation of anomalies on melt properties’ dependences upon temperature is made, for example, values of viscosity. The proposed approach allows analyzing properties of the melt and developing technological recommendations for production of materials possessing high characteristics.

Heat pumps are widely investigated for their versatile use in a wide range of applications. In this study, three types of heat pumps were experimentally compared. These heat pumps include an one-stage without injection vapor heat pump, an one-stage injection vapor heat hump and a two-stage injection vapor heat pump with an economizer. The results showed that the heating capacity of all three variants of heat pumps decreases with the decrease of the evaporation temperature. However, the attenuation ratio of the heating capacity is found to be different from one pump to another. On the one hand, the largest attenuation rate is found to be 68.84% for evaporating temperatures ranging from −1 °C to −23 °C and for the case of one-stage heat pump. On the other hand, the smallest attenuation rate is found to be 31% for the two-stage injection vapor heat pump in the same temperature range. It is worth noting that the heating efficiency is improved by the amount of vapor injection, nevertheless, there is a maximum value due to the limitations of the economizer. The two-stage injection vapor heat pump can exhibit an enhanced heating efficiency of 127% compared to the one-stage without injection vapor heat pump and 13% compared to the one-stage injection vapor heat pump for an evaporating temperature of −23 °C.

Radioactive contamination presents a diverse range of challenges in many industries. Determination of radioactive contamination depth plays a vital role in the assessment of contaminated sites, because it can be used to estimate the activity content. It is determined traditionally by measuring the activity distributions along the depth. This approach gives accurate results, but it is time consuming, lengthy and costly. The multiple photopeaks method was developed in this work for (226)Ra contamination depth determination in a NORM contaminated soil using in-situ gamma spectrometry. The developed method bases on linear correlation between the attenuation ratio of different gamma lines emitted by (214)Bi and the (226)Ra contamination depth. Although this method is approximate, but it is much simpler, faster and cheaper than the traditional one. This method can be applied for any case of multiple gamma emitter contaminant.

A significant number of studies have been conducted on the tensile properties of GFRP bars embedded in concrete under different environments. However, most of these studies have been experimentally based on the environmental immersion test after standard-curing and the lack of influence on the tensile properties of GFRP bars embedded in concrete during the curing process of concrete. This paper presents the results of the microscopic structures through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and tensile properties of GFRP bars, which were employed to investigate the combined effects of curing temperatures and alkaline concrete on tensile properties of GFRP bars. The results showed that the higher curing temperature aggravated the influence of the alkaline concrete environment on GFRP bars but did not change the mechanisms of mechanical degradation of the GFRP bars. The influence of different curing temperatures on the tensile strength of GFRP bars was different between the bare bar and bars in concrete. Finally, the exponential correlation equation of two different test methods was established, and the attenuation ratio of the tensile strength of GFRP bars embedded in concrete under different curing temperatures was predicted by the bare test.

The properties of the structural silicone sealant under standard condition and after aging conditions were characterized. The results showed that the structural silicone sealant had very good ability to resist the ultraviolet in the long time. In the other aging environment conditions, the different failure time for the structural silicone sealant were appeared. The value of the maximum strength under the different mechanical aging factors obviously existed in the structural silicone sealant with different compositions. The residual strength that the attenuation ratio is more than 75% standard strength would keep the ultra high-rise building curtains safe and sustainable.

Cement-based material samples having 0%, 5%, 10% and 20% B4C concentrations have been prepared for this reserach. Neutron attenuation measurement has been done by using 14.8MeV neutrons from the 5SDH-2 accelerator, and some mechanics properties of the same proportion also have been tested. It has been shown that when the B4C precentage and thickness of the samples increase, neutron attenuation values of the samples increase. Both the flexural and compressive strength firstly increased with B4C addition up to 10% approximately, and then decreased sharply with an addition up to 20%. It is thus possible to enhance the neutron shielding property of cement-based materials by adding B4C.

Experiments have been conducted to determine the effects of parallel and variable directional joints on ultrasonic pulse propagation in two 60 × 60 × 360 mm prismatic marble blocks containing no joints, six parallel joints, and six variable directional joints. The results indicated that the attenuation increases with increasing ratio of joints in both models, but the attenuation ratio was higher for the variable directional jointed model than for the model with parallel joints. The relationships between the number of joints and ultrasonic pulse velocities were statistically investigated and the results were evaluated with those found in literature.

This study presents the behavior characteristics of buried three-layered pipeline subjected to pile driving loads corresponding to its cover depth. The analysis considered the driving energy caused by 7 tonf of ram weight and 1.2m of stroke with 20m distance from buried pipeline for all the analysis cases. A cover depth of pipe is varied 0.6m to 3.8m for this research. Vibration Velocity and stress are investigated at the center section in longitudinal direction. With same distance from pile, attenuation ratio of vibration velocity for increment of cover depth has shown an increasing trend. Also, Stress attenuation ratio of inner pipe is increased with cover depth.

This study presents the behavior characteristics of buried three-layered pipeline subjected to pile driving loads. The analysis considered the driving energy caused by 7 tonf of ram weight and 1.2m of stroke. Also the distance from vibration resource to pipeline varies in 5m to 30m. The vibration velocity and stress are investigated at the center of pipeline in longitudinal direction. In the same cover depth, attenuation ratio of vibration velocity and von Mises stresses for distance increment has shown a decreasing trend. The maximum stress occurs at the top and bottom for the inner pipe, however, an irregular stress distribution is found for the outer pipe.

Through the analysis of the stress distribution in anchorage zone of bridge pylon with different placements of tendon, the placement with the equal coefficient of anti-crack in both sides is proposed. At the same time, several models whose outsides are crossed by tendons at different angles are analyzed. Compared the corresponding cracking loads and cracking place of them, a reasonable angle range is obtained. At last, the vertical attenuation ratio of the prestressing in the anchorage zone under the tendon is analyzed to give the appropriate distance between the adjacent tendons.

Wide dynamic range images (WDRIs) are needed for capturing scenes which include drastic lighting changes. This paper presents a method to widen the dynamic range of a camera by using a reflective liquid crystal. The system consists of a camera and a reflective liquid crystal placed in front of the camera. By controlling the attenuation ratio of the liquid crystal, scene radiance of each pixel is controlled adaptively. After applying the control, the original scene radiance is derived from the attenuation ratio of the liquid crystal and the radiance obtained by the camera. We have implemented a prototype system and conducted experiments in a scene that includes drastic lighting changes. These lighting changes require that we control the radiance of each pixel independently. We show how WDRIs are obtained by calculating the original scene radiance from these results.

Cancellation performance of a loop-current array shielding module depends on the overcompensation method used to adjust current in the loops. In previous experiments we used a single value as an overcompensation factor to all of the loops in the array. In this paper a new method of the overcompensation is proposed and verified numerically. In this method overcompensation factors are calculated independently for each of the loop-current. Simulation results show almost two times improvement in the attenuation ratio and 6-8 times expanding of the best cancellation area by the new method. An example of the implementation of the proposed overcompensation method is described in the paper.

Objective methods for mechanical assessment of mouthguards used for a prolonged period of time are currently unavailable. The aim of this experimental study was to establish a quantitative method for assessing the preventive effect of mouthguards. 10 participants volunteered for this study. Impact loads were simulated by dropping a 250-g steel rod from a height of 100 mm onto upper front teeth of 10 custom ethylene vinyl acetate mouthguards fixed to a steel receiving rod. The mean output from load cells equilaterally placed between plates at the base of the apparatus was measured as the impact pressure (N). Its attenuation ratio (%) was calculated as the ratio of the difference in impact pressures without and with a mouthguard to impact pressure without a mouthguard. Impact pressure with mouthguard was approximately 60% of that without mouthguard in all cases. Intraclass correlations showed excellent intra-rater and inter-rater reliability for attenuation ratio (0.98 and 0.94, respectively). Bland-Altman plots indicated lack of systematic bias. The results suggest that attenuation ratio of impact pressure calculated by the proposed method is a valid criterion for assessing the preventive effect of mouthguards. The method may enable early detection of mouthguard deterioration and their timely replacement.

Purpose Currently, lead-free x-ray-protective clothing is classified by the European production standard EN 61 331-3. To evaluate protective effects of lead-free materials according to this standard, the certifying offices as well as customers solely refer to the lead equivalent (LE). The LE of lead-free protective clothing, however, depends on the tube voltage (energy spectrum). Therefore, stating a single value for x-ray-protective clothing does not reveal the protective efficacy for the complete range of energy as applied in clinical practice. Moreover, the method of narrow beam geometry does not account for information on secondary radiation (scattered and fluorescent radiation) generated within the material. Lead-free materials, however, generate large-scale fluorescent radiation, especially for elements with atomic numbers below 60. As a consequence, full-scale secondary radiation of a given material can only be detected with a broad beam setup. Materials and methods In accordance with IEC 61 331-1, we compared commercially available radiation-protective aprons manufactured with lead-free or partially lead-free materials with aprons manufactured on a lead-oxide basis. In addition to the LE, attenuation ratios and dose-build-up-factors under broad beam-conditions were evaluated. Results In comparison with lead-oxide materials, protection efficacy of lead-free materials is reduced by up to 70 %, particularly for a tube voltage below 80 kV. Lead-composite materials (partially lead-free materials) are less affected. Conclusion Users and patients wearing lead-free x-ray-protective clothing might unknowingly be exposed to a much larger dose than generally assumed. In the future, radiation protection rating should exclusively refer to the "attenuation ratio", which is based on broad beam geometry and characterizes radiation attenuation much more precisely than the lead equivalent.

The use of models to predict indoor air quality and health risk for the soil vapor transport to indoor air pathway is commonplace; however, there is significant uncertainty surrounding processes and factors affecting this pathway, and the accuracy of models used. Available screening models were evaluated through a review of model characteristics and sensitivity, and through comparisons to measured conditions at field sites. Model simulations and comparisons to field data indicate that the vapor attenuation ratio (α) is highly sensitive to certain processes (e.g., biodegradation and ad-vection) and input parameters. Comparisons of model predicted to measured a values indicate that models based on the Johnson and Ettinger (1991) framework in most cases result in predictions that are conservative by up to one to two orders of magnitude for field sites that were assessed, providing that appropriate input parameters are used. However, for sites where the advection potential is high, these models may not be con...

To quantify visual attention objectively using the visual-evoked potential (VEP) in those having mild traumatic brain injury (mTBI) with and without a self-reported attentional deficit.Subjects were comprised of 16 adults with mTBI: 11 with an attentional deficit and five without. Three test conditions were used to assess the visual attentional state to quantify objectively the VEP alpha band attenuation ratio (AR) related to attention: (1) pattern VEP; (2) eyes-closed; and (3) eyes-closed number counting. The AR was calculated for both the individual and combined alpha frequencies (8-13 Hz). The objective results were compared to two subjective tests of visual and general attention (i.e. the VSAT and ASRS, respectively).The AR for both the individual and combined alpha frequencies was found to be abnormal in those with mTBI having an attentional deficit. In contrast, the AR was normal in those with mTBI but without an attentional deficit. The AR correlated with the ASRS, but not with the VSAT, test scores.The objective and subjective tests were able to differentiate between those having mTBI with and without an attentional deficit. The proposed VEP protocol can be used in the clinic to detect and assess objectively and reliably a visual attentional deficit in the mTBI population.

Synchrotron radiation computed laminography (SR-CL) has been in use in three-dimensional non-destructive imaging of flat objects for several years. A new set-up is proposed based on the traditional SR-CL method but with the detector inclined at the same angle as the sample inclination to collect projections. The results of computer simulations and real-sample experiments demonstrate that reconstructions acquired using an inclined detector are of better quality compared with those acquired using ordinary detecting methods, especially for the situation of few projections and small difference of attenuation ratio of the sample. This method could be applied to obtain high-quality images of weak-contrast samples with short measurement time and mild radiation damage.