Table Height Research Articles

Delfland in 1200. Een gereconstrueerde hoogtekaart

Abstract Delfland in 1200. A reconstructed elevation map In this study, a proxy is presented for the height of the land above sea level in the past. The height is calculated for the area of the Hoogheemraadschap (water board) of Delfland in the year 1200, based on the changes in the water table in the polders over time. Since 1865, this water table is presented in the Waterschapskaart of the Netherlands, which has seen f ive updates and is now replaced by maps of the individual water boards. These six measurements over a period of 155 years are used to calculate the rate of subsidence of the soil. Together with the present height of the water table above sea level, it is possible to extrapolate back in time to the year 1200. Such an extrapolation well outside the measurement area must be regarded with caution and the quantitative results are compared with expectations based on known geophysical processes in peat and clay soils and the history of the area. The calculated relief in 1200 matches with the expectancies based on the geographical survey of the area. As expected, the f irst dykes along the estuary were merely ment to ward off extreme high water in the summertime when wheat had to be protected against salt water. The clay soils are calculated to lay extremely f lat from the river to 20 kilometre inland. This allows for the observed linear flow of the rivers. According to the calculation, the height of the land above sea level is such that storm surges are expected to reach inland on only rare occasions. This is substantiated by the observation that farms are built on platforms of only a few decimetres in height. The method has proved its worth for an area the size of Delfland, where statistically significant results may be obtained due to the number of measurements. However, for results on a smaller scale the method is not sensitive enough.

Face coverings and respiratory tract droplet dispersion.

Respiratory droplets are the primary transmission route for SARS-CoV-2, a principle which drives social distancing guidelines. Evidence suggests that virus transmission can be reduced by face coverings, but robust evidence for how mask usage might affect safe distancing parameters is lacking. Accordingly, we set out to quantify the effects of face coverings on respiratory tract droplet deposition. We tested an anatomically realistic manikin head which ejected fluorescent droplets of water and human volunteers, in speaking and coughing conditions without a face covering, or with a surgical mask or a single-layer cotton face covering. We quantified the number of droplets in flight using laser sheet illumination and UV-light for those that had landed at table height at up to 2 m. For human volunteers, expiratory droplets were caught on a microscope slide 5 cm from the mouth. Whether manikin or human, wearing a face covering decreased the number of projected droplets by less than 1000-fold. We estimated that a person standing 2 m from someone coughing without a mask is exposed to over 10 000 times more respiratory droplets than from someone standing 0.5 m away wearing a basic single-layer mask. Our results indicate that face coverings show consistent efficacy at blocking respiratory droplets and thus provide an opportunity to moderate social distancing policies. However, the methodologies we employed mostly detect larger (non-aerosol) sized droplets. If the aerosol transmission is later determined to be a significant driver of infection, then our findings may overestimate the effectiveness of face coverings.

Inadequate object positioning and improvement of automatic exposure control system calculations based on an empirical algorithm.

When using automatic exposure control (AEC) systems in computed tomography (CT), miscalculation of tube current occurs when a patient is not aligned with the rotational center of the X-ray tube. A positioning compensation mechanism provides a corrective function when the patient is off-center; however, not all CT systems are equipped with this mechanism. AEC systems can broadly be divided into noise- and empirical-based. The authors studied empirical-based AEC systems to derive a compensation process to achieve an equivalent effect to that offered by the mechanism and to verify the accuracy of this process. A relational equation was derived to keep the tube current constant with variations in table height and quality reference milliampere-seconds (QRmAs), and this was adopted as the proposed compensation method. The radiation dose and image quality were evaluated for phantom imaging with and without the proposed compensation method using AEC and varying table heights. The output radiation dose and image quality were also evaluated for anthropomorphic chest phantom imaging to verify the compensatory effect of the proposed method. With the proposed compensation method, changes in the table height resulted in only small changes in the output radiation dose and noise level. Conversely, when the proposed compensation method was not used, changes in the table height resulted in widely varying output radiation dose and noise level. Imaging the anthropomorphic chest phantom with the proposed compensation method also yielded a stable output radiation dose.

Evaluation of a Low-Dose Radiation Protocol During Transcatheter Aortic Valve Implantation

We aimed to evaluate the efficacy and safety of a low-dose imaging protocol to reduce intraprocedural radiation during transcatheter aortic valve implantation (TAVI). Observational analysis: 802 transfemoral TAVI patients receiving balloon-expandable devices ≥23 mm at a high-volume centre. After propensity score matching, a standard-dose group (SD, n = 333) treated between January 2014 and February 2016 was compared with a low-dose group (LD, n = 333) treated between August 2017 and March 2019 after departmental uptake of a low-dose imaging protocol (reduced field size, high table height, use of "fluoro save," 3.75 frames/second acquisition, increased filtering). Primary end point was dose-area product (DAP). Secondary safety end points were VARC-2 device success and a composite of in-hospital complications. The LD protocol was associated with lower DAP (4.64 [2.93, 8.42] vs 22.73 [12.31, 34.58] Gy⋅cm2, p <0.001) and fluoroscopy time (10.4 [8.1, 13.9] vs 11.5 [9.1, 15.3] minutes, p = 0.001). Contrast use was higher in the LD group (LD 110 [94, 130] vs SD 100 [80, 135] milliliters, p = 0.042). Device success (LD 88.3% vs SD 91.3%, p = 0.25), and the composite end point (LD 8.1% vs SD 11.4%, p = 0.19) were similar. In multivariate analysis, the low-dose protocol was associated with a 19.8 Gy⋅cm2 reduction in procedural DAP (p <0.001). In conclusion, compared with standard imaging, a low-dose protocol for TAVI significantly reduced radiation dose without compromising outcomes.

Laparoscopic Excision of Recurrent Pelvic Lymphocyst Following Pelvic Lymph Node Dissection for Clear Cell Carcinoma of Ovary

Study ObjectiveDemonstration of safe laparoscopic technique for definitive excision of recurrent pelvic lymphocyst developing following pelvic lymph node dissection for clear cell carcinoma of the ovary; overcoming the additional surgical challenges of close proximity to vital anatomical structures and dense post-operative adhesions.DesignSurgical video detailing a systematic approach to laparoscopic excision of pelvic lymphocyst - describing individual surgical steps and highlighting relevant anatomy.SettingSurgery was undertaken by a gynae-oncology consultant with one surgical assistant. The patient was positioned in modified Lloyd-Davis – with table height and stack adjusted for optimal ergonomics.Patients or ParticipantsA 68 year old lady underwent total abdominal hysterectomy, bilateral salpingo-oophrectomy and omentectomy in April 2018 for stage 1A clear cell carcinoma of ovary; followed by completion laparoscopic pelvic and para-aortic lymphadenectomy. The patient subsequently developed a right pelvic lymphocyst, causing pain. Pre-operative imaging described a 3.9 × 3.3 × 3 centimetre right pelvic lymphocyst, with internal septations and thick wall. Two attempts at percutaneous drainage were unsuccessful due to difficulty penetrating the cyst capsule and loculated interior.InterventionsLaparoscopic excision of pelvic lymphocyst was undertaken. Pneumoperitoneum was maintained at a pressure of 12mmHG throughout. The pelvic peritoneum overlying the lymphocyst was opened and plane developed using a combination of monopolar, bipolar and advanced energy devices. The ureter and iliac vessels were systematically identified to avoid inadvertent injury; and avascular pelvic spaces developed to aid cleavage of the capsule with minimal blood loss.Measurements and Main ResultsNo intra or post-operative complications occurred. Histopathology confirmed a benign lymphocyst. At post-operative review, the patient reported resolution of pain and improved mobility.ConclusionThis video demonstrates a safe laparoscopic approach to excision of a densely adherent pelvic lymphocyst, abutting important pelvic structures – facilitated by the step-wise identification of pelvic anatomy and relevant pelvic spaces.

Tiller Size and Water Table Effects in Celery Growth on Floating Cultivation System

Jaya KK, Lakitan B, Bernas SM. 2020. Tiller size and water table effects in celery growth on floating cultivation system. Jurnal Lahan Suboptimal : Journal of Suboptimal Lands 9(2): 184-191.Riparian wetland is highly available and potential suboptimal lands for an alternative solution in extending agricultural activity, but several constrains need to be resolved. The objective of this study was to improve the diversification of vegetables for increasing riparian wetland with utilizing floating cultivation system. This study was conducted From November until December 2019 in Jakabaring (104°46’4” E; 3°01’35” S) Palembang. The design of experiments used in this study was arranged in split plot-completely randomized design with 2 factors (main plot and sub-plot). Main plot was the height of water table, namely: R1 (1 cm upper raft surface), R5 (5 cm upper raft surface), and R10 (10 cm upper raft surface). Sub-plot was the size of celery tiller, i.e., B1 (big size) and B2 (small size). Each combination treatment consisted of five replication. Results showed that there was no any significant effect on water table and tiller size combination treatments in all observed variables, such as: plant height, leaf area, number of petioles, root length, fresh weight, and dry weight of shoot and roots. But, root length was significant different in water table treatment. Therefore, cultivated celery using floating culture system from tiller of parent plants can be an alternative to increase agriculture activity by shortening the planting period to increase vegetable diversification in riparian wetland.

Taller staff occupationally exposed to less radiation to the temple in cardiac procedures, but risk higher doses during vascular cases

This study aimed to evaluate the effect of nurse and doctor height on occupational dose to the temple during fluoroscopically guided cardiovascular procedures. Additionally, an evaluation of the relationship between doctor height and table height was performed. Staff exposed during fluoroscopic procedures may be at elevated risk of cardiovascular damage or oncogenesis and have demonstrated a higher incidence of subscapular cataracts. The heads of taller staff may be exposed to reduced levels of radiation due to the increased distance from the area of highest intensity X-ray scatter. Limited research has been performed investigating height as a predictor of head dose to nursing staff. The level of radiation dose at the level of the temple to the doctor (n = 25), scrub (n = 28), and scout nurse (n = 29) was measured in a prospective single-center, observational study using Philips DoseAware badges. Procedural characteristics were recorded for vascular and cardiac cases performed in three dedicated angiography suites. Data were also collected to investigate relationships between doctor height and table height. Data were collected for 1585 cardiac and 294 vascular procedures. Staff height was a statistically significant predictor of temple dose for doctors, scrub, and scout nurses when considering the full data sample. The log temple dose demonstrated an inverse relationship to staff height during cardiac procedures, but a positive relationship for scrub and scout nurses during vascular studies. This observational study has demonstrated that taller staff are exposed to less cranial exposure dose during fluoroscopically guided cardiac examinations but has revealed a positive correlation between height and temple dose during vascular procedures. It was also determined that doctor height was correlated with average procedural table height and that vascular access point influences the choice of table elevation.

Fusion Imaging with a Mobile C-Arm for Peripheral Arterial Disease

Fusion imaging makes it possible to improve endovascular procedures and is mainly used in hybrid rooms for aortic procedures. The objective of this study was to evaluate the feasibility of fusion imaging for femoropopliteal endovascular procedures with a mobile flat plane sensor and dedicated software to assist endovascular navigation. Between May and December 2017, 41 patients requiring femoropopliteal endovascular revascularization were included. Interventions were carried out in a conventional surgical room equipped with a mobile plane sensor (Cios Alpha, Siemens). The numerical video stream was transmitted to an angionavigation station (EndoNaut (EN), Therenva). The software created an osseous and arterial panorama of the treated limb from the angiographies carried out at the beginning of procedure. After each displacement of the table, the software relocated the current image on the osseous panorama, with 2D-2D resetting, and amalgamated the mask of the arterial panorama. The success rates of creation of osseous and arterial panorama and the success of relocation were evaluated. The data concerning irradiation, the volume of contrast (VC) injected, and operative times were recorded. Osseous panoramas could be automatically generated for the 41 procedures, without manual adjustment in 33 cases (80.5%). About 35 relocations based on a 2D-2D resetting could be obtained in the 41 procedures, with a success rate of 85%. The causes of failure were a change in table height or arch angulation. The average duration of intervention was 74.5min. The irradiation parameters were duration of fluoroscopy 17.8±13.1min, air kerma 80.5±68.4mGy, and dose area product 2140±1599μGym2. The average VC was 24.5±14mL. This preliminary study showed that fusion imaging is possible in a nonhybrid room for peripheral procedures. Imagery of mobile C-arms can be improved for femoropopliteal endovascular procedures without heavy equipment. These imagery tools bring an operative comfort and could probably reduce irradiation and the injected VC. The clinical benefit must be evaluated in more patients in a randomized comparative study with a rigorous methodology.

Association between distance from the radiation source and radiation exposure: A phantom‐based study

The study evaluated the association between distance from radiation source and radiation exposure. Radiation exposure during medical procedures is associated with increased risk of cancer and other adverse effects. An American National Standards Institute phantom was used to study the relationship between measured entrance surface exposure (MESE) and distance from the X-ray source in postero-anterior, left anterior oblique, and right anterior oblique projections. Three distance settings for table height were evaluated with "low" defined as 52 cm, "mid" 66 cm, and "high" 80 cm from the focal point of the X-ray source. Air-kerma and dose-area product measurements were recorded. Operator exposure with each of these conditions was measured, in a short operator (150 cm) as well as in a tall operator (190 cm). Aggregate results for the three projections were as follows. MESE (μGy/frame) significantly decreased as table-height increases (median, interquartile range, p-value) (low table-height 192.5 [122.4-201.2], mid table-height 105.8 [82.7-115.8], and high table-height 71.7 [58.4-75], p < .0005). The operator exposure (μGy/frame), significantly increased as the table-height increased (low table-height 0.0943 [0.0598-0.1157], medium table-height 0.1128 [0.0919-0.1397], and high table-height 0.158 [0.1339-0.2165], p < .0005). A shorter operator received higher radiation exposure compared to a taller operator (short operator 0.1405 [0.1155-0.1758] and tall operator 0.0995 [0.0798-0.1212], p < .0005). Increasing table-height is associated with a significant decrease in MESE. Operator radiation exposure increases with increasing table-height and shorter operators receive greater radiation exposure compared to taller operators.

Automated patient positioning in CT using a 3D camera for body contour detection: accuracy in pediatric patients

ObjectiveTo assess the accuracy of a 3D camera for body contour detection in pediatric patient positioning in CT compared with routine manual positioning by radiographers.Methods and materialsOne hundred and ninety-one patients, with and without fixation aid, which underwent CT of the head, thorax, and/or abdomen on a scanner with manual table height selection and with table height suggestion by a 3D camera were retrospectively included. The ideal table height was defined as the position at which the scanner isocenter coincides with the patient’s isocenter. Table heights suggested by the camera and selected by the radiographer were compared with the ideal height.ResultsFor pediatric patients without fixation aid like a baby cradle or vacuum cushion and positioned by radiographers, the median (interquartile range) absolute table height deviation in mm was 10.2 (16.8) for abdomen, 16.4 (16.6) for head, 4.1 (5.1) for thorax-abdomen, and 9.7 (9.7) for thorax CT scans. The deviation was less for the 3D camera: 3.1 (4.7) for abdomen, 3.9 (6.3) for head, 2.2 (4.3) for thorax-abdomen, and 4.8 (6.7) for thorax CT scans (p < 0.05 for all body parts combined).ConclusionA 3D camera for body contour detection allows for automated and more accurate pediatric patient positioning than manual positioning done by radiographers, resulting in overall significantly smaller deviations from the ideal table height. The 3D camera may be also useful in the positioning of patients with fixation aid; however, evaluation of possible improvements in positioning accuracy was limited by the small sample size.Key Points• A 3D camera for body contour detection allows for automated and accurate pediatric patient positioning in CT.• A 3D camera outperformed radiographers in positioning pediatric patients without a fixation aid in CT.• Positioning of pediatric patients with fixation aid was feasible using the 3D camera, but no definite conclusions were drawn regarding the positioning accuracy due to the small sample size.

How Simulations of the Land Carbon Sink Are Biased by Ignoring Fluvial Carbon Transfers: A Case Study for the Amazon Basin

Summary Land-surface models are important tools for simulation of the past, present, and future capacity of terrestrial ecosystems to absorb anthropogenic CO2 emissions. However, fluvial carbon (C) transfers are presently neglected in these models. Using the Amazon basin as a case study, we show that this negligence leads to significant underestimation of the net uptake of atmospheric C while terrestrial C storage changes are overestimated. These biases arise from the fact that C—in reality, leached from soils and exported through the river network—is instead represented as partly being respired and partly being stored in soils. Moreover, these biases scale mainly to the fluvial C export to the coast, despite aquatic CO2 emission to the atmosphere being the major pathway of riverine C exports. We further show that fluvial C transfers may change significantly in response to changes in either hydrology or in atmospheric C uptake by vegetation.

Effect of miscentering and low-dose protocols on contrast resolution in computed tomography head examination

BackgroundUnoptimized protocols, including a miscentered position, might affect the outcome of diagnostic in CT examinations. In this study, we investigate the effects of miscentering position during CT head examination on the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). MethodWe simulate the CT head examination using a water phantom with a standard protocol (120 kVp/180 mAs) and a low dose protocol (100 kVp/142 mAs). The table height was adjusted to simulate miscentering by 5 cm from the isocenter, where the height was miscentered superiorly (MCS) at 109, 114, 119, and 124 cm, and miscentered inferiorly (MCI) at 99, 94, 89, and 84 cm. Seven circular regions of interest were used, with one drawn at the center, four at the peripheral area of the phantom, and two at the background area of the image. ResultsFor the standard protocol, the mean CNR decreased uniformly as table height increased and significantly differed (p < 0.05) at +20 cm for MCS (435.70 ± 9.39) and −20 cm for MCI (438.91 ± 10.94) from the isocenter. Similarly, significant reductions (p < 0.05) were also noted for SNR for MCS (at +20 cm) and MCI (at −20 cm). For the low dose protocol, both CNR and SNR were significantly reduced (p < 0.05) at table heights of +20 and −20 cm from the isocenter. ConclusionMiscentering is proven to significantly affect the image quality in both low and standard dose protocols for head CT procedure. This study implies that accurate patient centering is one of the approaches that can improve CT optimization practice.

A flexible ergonomic redesign of the sewing machine workstation

Purpose The apparel industry is a labor-intensive industry, which depends mainly on the performance of the worker. The purpose of this study is to present an ergonomic redesign of the sewing machine workstation, with different sewing table heights and inclination angles, based on the operator’s anthropometric data. Design/methodology/approach A flexible ergonomic sewing table has been designed, four main workstation-setting factors were studied; sewing desk inclination angles – X_1, height – X_2, sewing machine type – X_3 and operator’s body mass index (BMI) – X_4, with three levels for each factor, except sewing machine type, which only has two levels. The study was undertaken to specify the limitations and advantages of each combination tested. Different measurement techniques were used; subjective information, production rates – P, working postures (head, neck and trunk inclination angles in the kinematic stage) were measured. Findings Sewing operators’ sitting posture angles in the kinematic stage were affected more or less by their anthropometric measurements and the type of sewing machine. These two factors should be taken into consideration when ergonomically redesigning the sewing machine workstation. Practical implications A new ergonomically redesigned sewing machine table can be incorporated into garment factories, taking into consideration the BMI of the operators to improve their productivity and reduce musculoskeletal disorder complaints due to incorrect operators’ posture. Originality/value An important correlation was found between the sewing operator’s anthropometric body measurement – BMI and the type of sewing machine (with significant R^2 = 0.8385 and 0.9764 with both the head and neck inclination angles O_H, O_N, respectively).

Evaluation of ICESat-2 ATL08 Data Product: Performance Assessment in Inland Water

Advanced Topographic Laser System (ATLAS) instrument on-board NASA's Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) enabled the capability of detecting certain properties of the Earth's surface at a photon level. Primary applications of ICESat-2 are for cryosphere but extendable to measure and determine the changes in elevation for land terrain and canopy. ICESat-2 ATL08 data product is a level 3A product that contains the best fit height above a reference ellipsoid processed in fixed 100 m data segments, which typically uses more than 100 signal photons from level 2 product namely ATL03. In this article, ICESat-2 ATL08 has been evaluated for its accuracy. Accuracy assessment of a point ellipsoidal height can be done using known benchmarks or survey points. In the absence of known points, the performance of these points can be assessed by hydro-flatness test as well as by comparing the satellite observed surface water level with gauged water table height. Both these tests have been done on 5 large reservoirs in the Indian sub-continent. Hydro-flatness test on ICESat-2’s ATL08 data product determined the permissible variations that occur on the surface water body due to ripples, wavelets, and streaks at a centimeter-level. Water level from ICESat-2 data will be in ellipsoidal height and cannot be compared with gauged data as it gives the height of the water surface above an established altitude where the stage is zero, because of this we have compared the change of surface water level from different dates. The results indicate that the surface water levels from ICESat-2’s ATL08 data product are in line with gauged data at centimeter-level accuracy.

Increases in Greenhouse Gases Following the Use of Peatlands for Agricultural Areas

Peatlands with very high C contents are generally considered a source of greenhouse gas (GHG) emissions. This research aimed to quantify the changes in peatland characteristics and GHG emission from the conversion of peatlands to agricultural areas. Height of water table, pH, electrical conductivity (EC), redox potential (Eh), organic carbon (OC), hot water-soluble C, total-N, the concentrations of NH4 +, and NO3 −, soluble-Al, soluble- Fe, and the emission of CH4, CO2 and N2O were quantified before and after land clearing of peats for agriculture. Results of study showed that pH, EC, OC contents, hot water-soluble-C, and total-N did not change after peatland clearing for agriculture. On the other hand, the concentrations of NH4 +, NO3 −, soluble-Al, soluble-Fe, redox potential and height of water table increased significantly after the peatland land clearing. Methane emissions from peatlands before peatland clearing were in the range of 0.13-0.22 mg C m−2 h−1 increased significantly to 0.14-0.31 mg C m−2 h−1 after the peatland clearing. The land clearing of peatlands for agricultural practices also caused increases in CO2 and NOx emissions by 85% and 76%, respectively. Changes in GGH emissions were not related to the changes in substrates quality of peats (OC contents, total-N and hot water- soluble-C). Results of the study indicate that increases in the GHG emission following the use of peatlands for agricultural areas are attributed to the changes in the peat characteristics.

Effect of table height displacement and patient center deviation on size-specific dose estimates calculated from computed tomography localizer radiographs.

The aim of this study is to evaluate the effect of table height displacement and patient center deviation along the [Formula: see text]-axis on size-specific dose estimate (SSDE) calculations based on computed tomography (CT) localizer radiographs in pediatric and adult abdominal CT examinations. CT localizer radiographs and CT axial images were acquired with table heights of - 5.0, - 2.5, 0.0 (center), 2.5, and 5.0cm using two acrylic self-made phantoms filled with water. Water-equivalent diameters ([Formula: see text]) were calculated from the CT localizer radiographs and CT axial images. Relative errors of SSDEs from the CT localizer radiographs to SSDEs from the CT axial images were calculated to evaluate the effect of table height displacement. Furthermore, patient center deviations and indices of SSDE overestimation were measured from the clinical data of 110 abdominal CT examinations. The relative errors of SSDEs in phantoms equivalent to 1-year-old and 20-year-old Japanese reference persons ranged from - 2.45% (table height of 50mm) to + 1.88% (- 50mm) and from - 4.22% (50mm) to + 3.79% (- 50mm), respectively. The largest center deviation in all patients ranged from - 43.1 to 21.5mm (median: - 14.4mm). The indices of SSDE overestimation for all patients ranged from - 16.2 to 6.9mm (median: - 2.2mm). We found that the effects of table height displacement and patient center deviation along the [Formula: see text]-axis on SSDEs calculated from CT localizer radiographs in pediatric phantoms were smaller compared to adult phantoms. In order to correct these patient center deviations, it is necessary to apply an appropriate correction technique in each section along the [Formula: see text]-axis.

Bank stability and toe erosion model as a decision tool for gully bank stabilization in sub humid Ethiopian highlands

Gullies that are expanding at alarming rate are responsible for the majority of soil losses in the (sub) humid highlands of Ethiopia. Few affordable and effective methods for gully erosion control are available in the highlands. The objective of the study was to develop cost-effective measures to halt gully expansion by determining stable-bank conditions under a variety of environmental situations using the Bank Stability and Toe Erosion Model (BSTEM). The study was carried out in the sub humid Debre Mawi watershed, located 30 km south of Lake Tana. Input data for the BSTEM model were collected using field surveys and soil sampling. After the BSTEM was tested on actual measured soil data, soil cohesion and internal friction angle were calibrated against observed gully bank retreat. Using the calibrated parameters, the model evaluated the stabilization of the existing gully bank under different scenarios in which groundwater table, bank angle and bank height, tension crack depth, vegetation, and toe protection were varied. Finally, the head-cut of the study gully was treated based on the model recommendation. The simulated results showed that a 5 m deep gully was stable under fully saturated conditions when the bank toe is protected, its upper surface is vegetated, and its bank angles do not exceed 45°. If the depth of the gully is less than 5 m or if its water table is deeper than 0.5 m, only regrading the gully bank to an angle of 45° can stabilize the gully. BSTEM showed to be an effective tool that can be used to evaluate gully control measures.

Temporal Variability in the Vertical Separation Distance of Septic System Drainfields Along the Southern Rhode Island Coast

Many coastal communities rely on individual onsite wastewater treatment (i.e., septic) systems to treat and disperse wastewater. Proper wastewater treatment in these systems depends on sufficient volume of unsaturated soil below the drainfield’s infiltrative surface. This is governed by the vertical separation distance—the distance between the groundwater table and the drainfield infiltrative surface—which is specified in (regulatory jurisdictions’ onsite wastewater system) regulations. Groundwater tables along the southern New England coast are rising due to sea-level rise, as well as changes in precipitation and water use patterns, which may compromise the functioning of existing septic systems. We used long-term shallow groundwater monitoring wells and ground-penetrating radar surveys of 10 drainfields in the southern Rhode Island coastal zone to determine whether septic system drainfields have adequate separation distance from the water table. Our results indicate that only 20% of tested systems are not impaired by elevated groundwater tables, while 40% of systems experience compromised separation distance at least 50% of the time. Surprisingly, 30% of systems in this study do not meet separation distance requirements at any time of the year. Neither age of system nor a system’s geographical relationship to a tidal water body was correlated with compromised separation distance. The observed compromised separation distances may be a result of inaccurate methods, specified by the regulations, to determine the height of the seasonal high water table. Our preliminary results suggest that enacting changes in the regulatory permitting process for coastal zone systems may help protect coastal drinking and surface water resources.

A Systematic Ergonomics Approach of Maintenance Workstation

The transportation systems contribute very vital role in growth of country, either it may private, public or own transportation system, and to keep the automobiles or machine in good condition without any interruption consistent corrective or preventive maintenance has to be done, and this maintenance activities should take the least time and cost of maintenance along with good quality, and to achieve this it is preferred to design a good maintenance workstation with a systematic ergonomic consideration which has a great influence on time, service, comfort, quality, productivity. For the design of a maintenance workstation, systematic ergonomic procedures are considered these procedures should concern for good ergonomically design of workstation. In an actual design of workstation ergonomically approach is needed concern of the worker anthropometric data with the various parameter of the workstation like adequate posture, work table or chair height, position of the operating nobs and levers comfortable sufficient working areas that help to reduce MSD (Musculoskeletal disorder) and prevent injuries of worker along with enhancing productivity. The main objective of this paper is to propose a systematic ergonomically designed maintenance workstation. Existing workstation of Maintenance in MSRTC (Maharashtra State Road Transport Corporation) Solapur workshop, is not designed with consideration of Ergonomic principle, so the ergonomic analysis has been made for different posture of maintenance activity, and modifications in workstation has been suggested. For analysis CATIA software is used, Manikin (simulated posture of worker) has been developed based on the anthropometric data collected from MSRTC for RULA analysis under quasi-static loading and dynamic loading conditions.

How table height influences image quality and radiation dose of chest CT scans with automatic exposure control: a phantom study?

To investigate the influence of table height on image quality and radiation dose of chest CT scan with automatic exposure control (AEC) technology. A chest phantom was scanned with AEC technology at 11 different table heights from 100 to 200 mm with 130 mm table height (iso-center was positioned at the midaxillary line of the phantom) used as reference center position. Image quality and radiation doses at different heights were statistically analyzed. Compared with 130 mm table height, the radiation dose of chest CT scan changed about 15% with the table height at 160 mm, or table height at 100 mm. The trend of the tube current–time (mAs) curve at different table heights was the same. In the thoracic inlet area, mAs changed most obviously, compared to the heart area. The noise of the image at higher table heights was not significantly different from the reference table height, but lower table heights increased the noise. When the height of the table was decreased from 130 to 100 mm, the size of the measured phantom changed greatly, by 5.22%, and when the height of the table was increased from 130 to 160 mm, the measured phantom size decreased to 95.07%. The score of the subjective image quality was lower when the table height was lowered. With table height settled between anterior axillary line and midaxillary line of the phantom, acceptable subjective image quality could be obtained with a lower radiation dose.