Cross-sectional Area Ratio Research Articles

Exfoliation of hexagonal boron nitride nanosheets assisted with covalent organic frameworks by ball-milling

Boron nitride nanosheets have superior chemical and physical properties. However, there are many problems in the preparation of hexagonal boron nitride nanosheets, and an effective exfoliation method is still lacking. To solve this problem, this paper intends to obtain boron nitride nanosheets by ball milling using TpPa from COFs material as a ball milling aid, and to investigate various factors affecting the ball milling effect. The h-BN obtained by using some other polymer materials such as starch and pvp as ball milling aids were compared with the h-BN peeled by using COFs materials as ball milling aids, and the results showed that the peeling effect of using TpPa as ball milling aids was not satisfactory because the structure of COFs materials was too stable. This paper also further conducted ball milling experiments on a variety of dry auxiliaries and compared them according to the ball milling effect The strength, friction, softening point and hardness were analyzed by machine learning. The analysis revealed that these aspects affect the cross-sectional area, thickness and aspect ratio of h-BN nanosheets. To obtain good h-BN nanosheets, the main conclusions of this paper are as follows: For the cross-sectional area of h-BNNS: the bond strength, friction, hardness and softening point of the ball milling agents have a strong influence on it and are positively correlated with it, while the friction and softening point of the ball milling agents are negatively correlated with it. For the thickness of h-BNNS: the bond strength and decomposition point of ball abrasives have influence on it, but not much, while hardness, softening point and contact angle have more influence on it, and hardness and contact angle are positively correlated with it, and softening point is negatively correlated with it. For the aspect ratio of h-BNNS: the hardness, softening point and contact angle of the ball abrasive have a greater effect on it, while the softening point has the greatest effect on it with a positive trend and the hardness and contact angle with a negative trend.

Micro-Computed Tomography Evaluation of Minimally Invasive Shaping Systems in Mandibular First Molars.

The aim of this study was to compare the shaping ability of a modified ProTaper Next technique (PTNm) with that of TruNatomy (TN) in lower molars mesial curved canals using micro-computed tomography (Micro-CT). Sixty mesial canals of first mandibular molars were randomly assigned between two groups (n = 30). After canal scouting with K-File #10, glide path and shaping were carried out with TN or PTNm systems. The PTNm sequence consists of ProGlider, followed by ProTaper Next X1 and apical finishing with NiTiFlex #25 up to working length (WL) to ensure adequate apical cleaning. Samples were scanned using micro-CT and pre- and post-shaping volumes were matched to analyse geometric parameters: the volume of removed dentin; the difference of canal surface; centroid shift, minimum and maximum root canal diameters; cross-sectional areas; the ratio of diameter ratios (RDR) and the ratio of cross-sectional areas (RA). Measurements were assessed 2 mm from the apex and in relation to the middle and coronal root canal thirds. Data were analysed using ANOVA (p < 0.05). No statistically significant differences were found between the groups for any parameter at each level of analysis, except for RA at the coronal level (p = 0.037). The PTNm system showed the tendency to enlarge more in the coronal portion with a lower centroid shift at apical level compared with TN sequence (p > 0.05). Both PTNm and TN sequences demonstrated similar maintenance of original anatomy during the shaping of lower molar mesial curved canals.

High Performance Fully Inkjet-Printed Organic Electrochemical Transistor (OECT) Biosensor

High throughput, high sensitivity, and scalability point-of-care biosensors have the potential to significantly improve diagnosis and disease monitoring. Organic electrochemical transistors (OECTs) are a powerful platform for point-of-care biosensing given their sensitivity and performance. Unfortunately, this is seldom achieved with novel and cost-effective fabrication methods. In this work, we built high-performance OECTs using state-of-the-art inkjet printing technology a, scalable, highly reproducible, and low-cost fabrication process. The design utilizes unique high conductivity PEDOT: PSS formulations driving higher ion-to-electron conversion, and volumetric capacitance reaching a value of 18.524 F cm−3. The design included a high ratio of channel cross-sectional area to length reaching a maximum corresponding transconductance (gm) value of 15.2 mS, an order of magnitude improvement on published work. The design was also tested with Bovine Serum Albumin (BSA) protein and showed a limit of detection on the order of 1 pM of BSA. This work shows the potential of inkjet printing for fabricating low-cost, high-performance OECT-based point-of-care biosensors.

The Effects of roof angle, inlet gap size and drying time on dryer mass flow rate and moisture content in a chimney-dependent solar crop dryer using design of experiments (DOE)

A chimney dependent solar crop dryer (CDSCD) was designed and developed. Design of Experiments (DOE) was used to carry out experiments using a statistical three level non randomized factorial experimental design in Minitab statistical software version 19.0. The effect of three drying parameters, roof angle (º), Inlet gap size (mm), and time (h) on dryer inlet mass flow rate (kg/s) and moisture content (%) were studied. The regression results showed that there was a satisfactory fit of the model variability for both dryer inlet mass flow rate and crop moisture content. The p-value for each parameter was less than 0.005, which is statistically significant. The R-squared (R2) value was 94.67% for inlet air mass flow rate study and 99.72% for moisture content. It was observed that the optimal values for achieving a low moisture content response (≤ 24%) were roof angle of 81º, inlet to outlet cross-sectional area ratio of 1.08768:1 and a minimum drying time of 24 hours while the optimal values for achieving high inlet air mass flow rate (≥ 0.357 kg/s) were roof angle of 51º, inlet to outlet cross-sectional area ratio of 1.08768:1 and a minimum drying time of 5 hours. The findings could be implemented and utilized for achieving optimum ventilation and drying performances to refine dryer (CDSCD) design.

Does the asymmetry and extension function of the preoperative cervical paraspinal extensor predict postoperative cervical sagittal deformity in patients who undergo modified laminoplasty?

BACKGROUND CONTEXTA previous study found that the cross-sectional area (CSA) of the preoperative cervical paraspinal extensors (CPEs) was associated with loss of cervical lordosis after laminoplasty, while a recent study found that CPE asymmetry was associated with symptoms of degenerative cervical myelopathy. Whether preoperative CPE asymmetry can predict cervical sagittal deformity (CSD) after laminoplasty is unknown. PURPOSETo assess whether asymmetry, degree of degeneration, and extension function of the CPE can be used as predictors of postoperative CSD in patients who undergo laminoplasty. STUDY DESIGNA retrospective study. PATIENT SAMPLEFrom January 2017 to December 2019, 55 patients with multilevel cord compression and myelopathic symptoms were enrolled. OUTCOME MEASURESThe visual analog scale (VAS), neck disability index (NDI), and modified Japanese Orthopedic Association (mJOA) were used to assess cervical spinal function and quality of life. METHODSFrom January 2017 to December 2019, 55 patients undergoing modified laminoplasty were included. The following parameters were measured preoperatively and 24 months postoperatively on X-ray: (1) C0–C2 Cobb angle; (2) C2–C7 Cobb angle (CL); (3) T1 slope (T1S); (5) C2–C7 sagittal vertical axis (SVA); (6) T1S minus CL; (7) Preoperative extension function: Extension CL minus Neutral CL (EF). Preoperative global alignment parameters: (8) spino cranial angle, (9) C7-S1 sagittal vertical axis (C7 SVA), (10) pelvic incidence, (11) lumbar lordosis, (12) thoracic kyphosis. (13) Preoperative CPE parameters: Summation of bilateral total cross-sectional area (STCSA), summation of bilateral total cross-sectional area ratio (STCSAR), total cross-sectional area asymmetry, summation of bilateral functional cross-sectional area of muscle (SFCSA), summation of bilateral functional cross-sectional area of muscle ratio (FCSAR), and functional cross-sectional area of muscle asymmetry (FCSAA). The VAS, mJOA, and NDI were used to evaluate cervical spine function and quality of life. Patients were divided into the CSD group and the non-deformed group (N-CSD) group postoperatively, and the parameters between the two groups were compared. The Pearson correlation coefficient was used to evaluate the relationship between the parameters, and multiple regression analysis and ROC curve analysis were used to determine the predictors and key values. RESULTSCompared with functional scores, mJOA in the CSD group was significantly lower than that in the N-CSD group, while NDI and VAS were significantly higher. Postoperative CL was significantly correlated with EF, SFCSA/STCSA (C3–C6), SFCSAR (C4 and C6), STCSAR (C6), and FSCAA (C6). T1S minus CL was significantly correlated with EF, SFCSA/STCSA (C3–4 and C6), SFCSAR (C4 and C6), STCSAR (C6) and FSCAA (C6). C2–7 SVA was significantly correlated with EF, SFCSAR (C4 and C6), STCSAR (C6), and FSCAA (C6). Multiple regression analysis showed that FCSAA (C6), SFCSAR (C6), SFCSAR (C4), and EF were significant predictors of postoperative CSD. ROC curve analysis showed that the optimal cutoff points were 18.405, 2.95, 4.47, and 11.96. CONCLUSIONSThe present study found that preoperative extension dysfunction of CPEs, asymmetry at the C6 level cervical extensors, and cervical extensor CSAs without fatty infiltration at the C4 and C6 levels were associated with cervical sagittal imbalance after modified laminoplasty. These factors can be considered when future spine surgeons formulate surgical plans.

Recycling alkaline fuel cell waste heat for cooling production via temperature-matching elastocaloric cooler

To recycle byproduct waste heat, a new hybrid system model that integrates alkaline fuel cell (AFC) with temperature-matching elastocaloric cooler (ECC) is proposed. Considering diverse irreversible effects in thermodynamic and electrochemical processes, the mathematical model of hybrid system is formulated, and the performance metrics of the hybrid system are obtained. The optimally operating current density range of AFC enabling ECC to work is determined. Numerical calculation shows that the equivalent peak output power density and its according efficiency can be 51.64% and 20.88% higher than that of the single AFC, respectively. ECC is demonstrated to be an effective and competitive technology for AFC waste heat harvesting. In addition, considerable sensitivity analyses are performed to check the dependence of the proposed system performance on some key variables, including operating pressure, operating temperature, thermodynamic loss composite parameter, elastocaloric material types and elastocaloric properties, cross-sectional area ratio and length ratio for ECC. The results derived may offer some insights into the design or operation of practical AFC-ECC hybrid systems.

Association of preoperative variables of ipsilateral hip abductor muscles with gait function after total hip arthroplasty: a retrospective study

BackgroundThis study aimed to identify the association of preoperative variables of ipsilateral hip abductors with gait function after total hip arthroplasty (THA).MethodsThis study enrolled 42 patients who underwent unilateral primary THA for osteoarthritis. Gait speed and Timed Up-and-Go test were conducted 6 months postoperatively. Preoperative composition of the glutei medius and minimus and the upper portion of gluteus maximus was evaluated by computed tomography. Cross-sectional area ratio of individual composition to the total muscle was calculated. Preoperative variables associated with gait speed and Timed Up-and-Go test after THA were identified by using stepwise regression analysis.ResultsFaster gait speed and shorter Timed Up-and-Go test correlated with smaller cross-sectional area of low-density lean tissue or intramuscular adipose tissue (low-density lean tissue plus intramuscular fat) in the glutei medius and minimus and lower cross-sectional area ratio of low-density lean tissue to the total glutei medius and minimus. Faster gait speed and shorter Timed Up-and-Go test also correlated with larger cross-sectional area of lean muscle mass in the gluteus maximus, higher cross-sectional area ratio of lean muscle mass to the total gluteus maximus, and lower cross-sectional area ratio of intramuscular fat or intramuscular adipose tissue to the total gluteus maximus. Faster gait speed additionally correlated with larger total cross-sectional area of the gluteus maximus. Regression analysis showed that the total cross-sectional area of the gluteus maximus and the low-density lean tissue cross-sectional area of the glutei medius and minimus were the explanatory variables of gait speed and Timed Up-and-Go test after THA, respectively.ConclusionsThere was a potential association between preoperative composition of ipsilateral hip abductors and gait function 6 months after THA. This study indicates a predictive role of preoperative assessment of ipsilateral hip abductor composition in the recovery of gait function after THA.

Assessment of Nasal Structure Using CT Imaging of Brachycephalic Dog Breeds.

Simple SummaryFrench bulldogs and pugs are classified as brachycephalic dogs and are characterized by short, stenotic noses. The outward characteristics of this breed can cause dyspnea, which may be surgically improved. However, brachycephalic dog breeds have different rates of disease progression and response to treatment. We hypothesized that this difference was due to the difference in the structure of the nasal cavity. To verify this, the ratio of the airway cross-sectional area to the total nasal cavity area was compared between the three brachycephalic dog breeds using head computed tomography (CT) images. The results revealed that the distribution of narrow and wide airway locations in the nasal cavity differed among the breeds. The method used in this study was suitable for observing and evaluating canine nasal structures. These results provide a new approach for the diagnosis of canine respiratory diseases and improve our understanding of the pathogenesis of brachycephalic dogs.The response to treatment of brachycephalic airway syndrome (BAS) varies among brachycephalic dog breeds. We hypothesized that variations in nasal structure are one of the factors responsible for this difference. To confirm this variation, we measured the ratio of the airway cross-sectional area to the total nasal cavity area (AA/NC) in three brachycephalic dog breeds. Head CT images of French bulldogs, shih tzus, and pugs were retrospectively collected. Four specific transverse planes were used to calculate AA/NC ratios. Fifty brachycephalic dogs were included in the study: French bulldogs (n = 20), shih tzus (n = 20), and pugs (n = 10). The AA/NC ratio of Shih Tzus was larger in the rostral nasal cavity and smaller toward the caudal area, whereas the other two breeds showed an inverse tendency. The results obtained from the current research indicate that the AA/NC ratio can be used to evaluate the structure of the nasal cavity. Moreover, analyzing the point with the smallest AA/NC ratio can be useful in quantifying nasal airway obstruction and the severity of BAS. These results will be useful in understanding the complexity of BAS pathophysiology and in the implementation of treatment.

Do Preoperative Vastus Medialis Volume and Quality Affect Functional Outcomes after Total Knee Arthroplasty?

Background: Vastus medialis function has been implicated in the development and progression of knee osteoarthritis; however, studies evaluating the influence of its preoperative volume and quality on functional outcomes following total knee arthroplasty (TKA) remain scarce. This study aimed to determine the association between vastus medialis volume, quality, and clinical outcomes after TKA. Methods: Among the patients who underwent unilateral TKA, 92 who had undergone magnetic resonance imaging (MRI) before TKA were included. Preoperative vastus medialis volume and quality were assessed using the cross-sectional area (CSA) and fat infiltration ratio on MRI. Clinical outcomes were evaluated using the Knee Society knee score (KSKS) and Knee Society function score (KSFS) at baseline and 1 year after surgery. The relationships between preoperative CSA, fatty infiltration ratio, and clinical outcomes were analyzed using univariate and multivariate linear regression. Results: Only the fatty infiltration ratio was significantly associated with postoperative KSFS in the univariate linear regression analysis. In the multivariate linear regression analysis, age and fatty infiltration ratio were significantly associated with postoperative KSFS. Conclusions: Increased vastus medialis fat infiltration is associated with worse functional outcomes after TKA. Preserving vastus medialis quality could improve functional outcomes, and surgeons should encourage patients to perform quadriceps strengthening exercises before surgery.

Nerve Ultrasound Findings in Carpal Tunnel Syndrome and its Correlation with Clinical and Electrophysiological Data

Background: Sonologic evaluation of the median nerve has been shown to be a useful tool in carpal tunnel syndrome diagnosis. Neurosonology supplants clinical and electrodiagnostic work up. Objectives: To determine the median nerve ultrasound parameters in carpal tunnel syndrome (CTS) patients and find their correlation with patient reported clinical data and electrophysiology findings,to assess diagnostic accuracy of nerve ultrasound in CTS in comparison to clinical evaluation combined with electrodiagnosis as reference standard. Methods: 23 consecutive patients with carpal tunnel syndrome symptoms (46 wrists-35 with nerve conduction study confirmed CTS, 11 without CTS) underwent neurosonologic evaluation with high resolution ultrasound including median nerve cross sectional area(CSA) at carpal tunnel inlet, flattening ratio, Wrist/forearm CSA ratio measurements. Patient reported measures were recorded using Boston carpal tunnel syndrome questionnaire (BCTQ). Results: Statistically significant correlation was found between median nerve CSA at carpal tunnel inlet and disease severity assessed by electrodiagnosis (r=0.545, p value-0.002), hand function status had significant correlation with electrodiagnostic severity class (r=0.422, p value 0.012). Flattening ratio, Wrist/forearm CSA ratio did not show significant correlation with clinical and electrophysiology measures. Sensitivity and specificity for a cross sectional area cut off of 9 cm2 for diagnosis of CTS was found to be 85.7 percent and 64 percent respectively. Conclusion: Median nerve cross sectional area CSA measurement is the most useful neurosonologic parameter and correlates with electrodiagnostic severity. Ultrasound is a useful complementary tool for CTS diagnosis, assessment alongside electrodiagnosis. Keywords: Carpal Tunnel Syndrome, Neurosonology, Compression neuropathy

Effects of cross-sectional area and aspect ratio coupled with orientation on mechanical properties and deformation behavior of Cu nanowires

Metal nanomaterials exhibit excellent mechanical properties compared with corresponding bulk materials and have potential applications in various areas. Despite a number of studies of the size effect on Cu nanowires mechanical properties with square cross-sectional, investigations of them in rectangular cross-sectional with various sizes at constant volume are rare, and lack of multifactor coupling effect on mechanical properties and quantitative investigation. In this work, the dependence of mechanical properties and deformation mechanisms of Cu nanowires/nanoplates under tension on cross-sessional area, aspect ratio of cross-sectional coupled with orientation were investigated using molecular dynamics simulations and the semi-empirical expressions related to mechanical properties were proposed. The simulation results show that the Young’s modulus and the yield stress sharply increase with the aspect ratio except for the 〈110〉{110}{001} Cu nanowires/nanoplates at the same cross-sectional area. And the Young’s modulus increases while the yield stress decreases with the cross-sectional area of Cu nanowires. However, both of them increase with the cross-sectional area of Cu nanoplates. Besides, the Young’s modulus increases with the cross-sectional area at all the orientations. The yield stress shows a mildly downward trend except for the 〈111〉 Cu nanowires with increased cross-sectional area. For the Cu nanowires with a small cross-sectional area, the surface force increases with the aspect ratio. In contrast, it decreases with the aspect ratio increase at a large cross-sectional area. At the cross-sectional area of 13.068 nm2, the surface force decreases with the aspect ratio of the 〈110〉 Cu nanowires while it increases at other orientations. The surface force is a linearly decreasing function of the cross-sectional area at different orientations. Quantitative studies show that Young’s modulus and yield stress to the aspect ratio of the Cu nanowires satisfy exponent relationship. In addition, the main deformation mechanism of Cu nanowires is the nucleation and propagation of partial dislocations while it is the twinning-dominated reorientation for Cu nanoplates.

Influence of geometric parameter and contact resistances on the thermal-electric behavior of a segmented TEG

Thermoelectric (TE) generation technology plays an increasingly significant role in a global environment. A desirable approach to improve the efficiency of thermoelectric generator (TEG) is to segment the n- and/or p-leg into several parts with different materials for increasing the average thermoelectric figure of merit of the legs, and to operate with a relatively larger temperature gradient. In this study, a three-dimensional model is developed for the performance analysis of a segmented TEG, and the geometric design optimization of the TEG is examined numerically with the use of the temperature-dependent thermoelectric materials. Specifically, the temperature, heat flow, electric potential, electric current and Joule heating in the thermoelectric modules are investigated in detail. Also, the efficiency and effectiveness of the TEG is analyzed with the design variables such as the ratio of cross-sectional area of p-leg and n-leg, the length ratio of different materials in the segmented leg, and the geometry configurations of p- and n-legs. Furthermore, the effect of the contact resistance on the TEG performance is considered. The results show that a proper design of the geometric parameters can lead to an optimal design of thermoelectric generation systems with higher efficiency.

Effect of Polymer Mixtures on Physical-Chemical Properties of Sandy Soil and Plant Growth

Serious desertification problems were found in alpine grassland of the Qinghai-Tibet Plateau, China. The rehabilitation progress of degraded grassland is slow under natural conditions that have low rainfall and large evaporation. Organic agent-solidified soil is one of the most important measurements that limit desertification and grassland conservation-restoration. However, the characteristics of vegetation growth and development in solidified soil need to be studied in depth. This research is based on the modified carboxymethyl cellulose (MCMC) of independent development. Based on the sand soil taken from moving sandy land of Zoige, potted plants were tested in the environmental chamber at the laboratory. The physical, chemical, and biological characteristics of root soil were monitored for more than 7 months. As a result, the plant biomass in the experimental group increased, lodging rate decreased, drought tolerance and survival rate increased, and the number of plant roots and root surface area index, root cross-sectional area ratio, and root volume ratio increased compared with the matched group. It is shown that MCMC can effectively promote plant root development and improve plant drought tolerance and lodging resistance. We also found that, compared with the matched group, the values of the rhizosphere soil mass, root soil mass, and soil crust layer thickness of the experimental group were much higher, meaning that MCMC has strengthened the root soil-fixation ability and soil-crusting ability of plants. The soil nutrient indexes and bioactivity of the experimental group were higher than the matched group, indicating that MCMC has a positive influence on soil maturation. The quantitative description model of soil aging enhancement of MCMC material during root growth and development was established to explore the soil-fixation mechanism of MCMC plant root succession and provided an important scientific basis and technical support for the conservation and restoration of alpine grassland desertification grassland.

Micro CT assessment of the effect of single and fractionated X radiation doses in rats tibias

The aim of this study was to evaluate the effect of X radiation in single and fractionated doses in tibias of rats by micro-computer tomography (µCT) analysis. The sample was consisted by 20 male rats, divided into 3 groups: Control, Single dose and Fractionated dose. The rats were submitted to a radiation X exposure on lower limbs. The single dose group was exposed to single radiation of 15 gray (Gy), while the fractionated group was submitted to three irradiation sessions of 5 Gy each, totaling 15 Gy. After 24 hours and 25 days, the rats were euthanized; the tibias were removed and scanned using a µCT unit, SkyScan 1174 Compact Micro-CT (Kontich, Bélgica). The parameters total bone area (Tt.Ar) , cortical bone area (Ct.Ar) , total cross-sectional bone area ratio (Ct.Ar / Tt.Ar) e cortical thickness (Ct.Th) for cortical bone, e bone volume ratio (BV / TV), trabecular number (Tb.N), trabecular thickness (Tb.Th) e trabecular separation (Tb.Sp), for trabecular bone analysis were evaluated. Data were submitted to one-way ANOVA and Tukey’s test (α = 0.05). The µCT evaluation showed significant differences on Tt.Ar and Tb.Sp parameters (p&lt;0,05). It was observed a lower Tt.Ar in the fractionated group compared to control, and higher Tb.Sp in the group receiving a single dose when compared to the control and fractionated groups. It is concluded, in relation to bone microarchitecture, that the radiation X in fractionated doses presents more deleterious effects on the cortical bone and when in singe doses, more damage on trabecular spaces, leading to a higher porosity.

만성 요통환자의 굽힘과 폄편향이 허리근육의 횡단면적과 근활성도에 미치는 영향

The purpose of study was to explore the influence of flexion and extension bias on the electromyographic (EMG) activities and cross-sectional area of lumbar muscles in chronic low back pain. twenty-two patients with chronic low back pain were divided into either flexion bias or extension bias groups by symptom provoking posture. The multifidus, iliopsoas, and erector spinae muscles were measured by magnetic reasoning imaging (MRI) and calculated with ratio by body of the 4th lumbar vertebra. EMG activities of multifidus and erector spinae was measured, and all the EMG amplitude were normalized into %maximum voluntary isometric contraction (%MVIC). Flexion bias group has significantly lower ratio of iliopsoas cross-sectional area than that of extension bias group (p<.05). As a result, flexion bias group has higher ratio of cross-sectional area of multifidus at the more involved side (p<.05). Flexion bias group has significantly higher %MVIC in erector spinae than extension bias group during trunk flexion and extension (p<.05). Consequently, the results of this study suggest that necessity of exercise for preventing multifidus muscle atrophy for flexion bias group.

THEORETICAL INVESTIGATION OF HYDRAULIC CHARACTERISTICS OF A DOWNHOLE EJECTION SYSTEM

To analyze the peculiarities of the local swirling of injected flow, there are studied design and technological parameters in the form of the inclination angle of guiding elements and the flow rates of the swirling flow. Based on the application of the conservation law of fluid momentum in adjacent jets with a parabolic pressure distribution, there are obtained equations to determine the pressure characteristic of a jet pump, taking into account the additional dynamic pressure made by swirling the injected flow. In the process of analyzing the obtained relations, there has been set the dependence of the relative pressure growth and the efficiency of the ejection system under the conditions of injected flow swirling on the relative flow rate of a jet pump and an inversely proportional dependence of the above parameters on its main geometric parameter in the form of the ratio of cross-sectional areas of the mixing chamber and the nozzle.

Deformation and cyclic behavior of partially-restrained energy dissipaters with yielding end connections

Partially-restrained Energy Dissipater (PED) is a metal hysteresis dissipative device and exhibits an excellent low-cycle fatigue performance. Each PED typically consists of an inner core and an outer restraining member. The inner core is manufactured from a steel rod, forming a milled portion (the fuse) to dissipate energy and two intact external portions (external bars) to connect with structural members. External bars were expected to remain elastic in prior studies and the cyclic responses of PEDs with yielding external bars were hardly discussed. In this paper, a total of eight PEDs were designed and tested to comprehensively investigate the hysteresis responses of PEDs with yielding external bars. The three variable parameters of the test were loading patterns, the unrestrained length of the external bar lur and the cross-sectional area ratio ρ of the fuse to the external bar. The test results illustrated that most of PEDs exhibited stable cyclic performances after external bars yielding and two failure modes were observed, including fuse fracture and end bending. Besides, a larger area ratio ρ significantly improved the low-cycle fatigue life and energy dissipation capacity of PEDs, meanwhile it increased the demand on the flexural stiffness of the external bar to avoid end bending. Finally, an analytical model was established for the deformation of the external bar and a design criteria was presented to avoid the end bending failure of PEDs with yielding end connections

Predictive Modeling of New-Onset Postoperative Diplopia Following Orbital Decompression for Thyroid Eye Disease.

To identify risk factors for the development of new-onset, postoperative diplopia following orbital decompression surgery based on patient demographics, clinical exam characteristics, radiographic parameters, and surgical techniques. We conducted a multi-center retrospective chart review of patients who underwent orbital decompression for thyroid eye disease (TED). Patient demographics, including age, gender, smoking history, preoperative exophthalmometry, clinical activity score (CAS), use of peribulbar and/or systemic steroids, and type of orbital decompression were reviewed. Postoperative diplopia was determined at a minimum of 3 months postoperatively and before any further surgeries. Cross-sectional area ratios of each extraocular muscle to orbit and total fat to orbit were calculated from coronal imaging in a standard fashion. All measurements were carried out using PACS imaging software. Multivariable logistic regression modeling was performed using Stata 14.2 (StataCorp, College Station, TX). A total of 331 patients without preoperative diplopia were identified. At 3 months postoperatively, 249 patients had no diplopia whereas 82 patients developed diplopia. The average postoperative follow-up was 22 months (range 3-156) months. Significant preoperative clinical risk factors for postoperative diplopia included older age at surgery, proptosis, use of peribulbar or systemic steroids, elevated clinical activity score, and presence of preoperative compressive optic neuropathy. Imaging findings of enlarged cross-sectional areas of each rectus muscle to the overall orbital area also conferred a significant risk of postoperative diplopia. Regarding surgical factors, postoperative diplopia was more common among those undergoing medial wall decompression, bilateral orbital surgery, and balanced decompression, whereas endoscopic medial wall decompression was found to be relatively protective. This study identifies risk factors associated with the development of diplopia following orbital decompression using multivariable data. This study demonstrates that several characteristics including age, clinical activity score, the cross-sectional muscle to orbit ratios, in addition to the type of orbital decompression surgery, are predictive factors for the development of new-onset postoperative diplopia.

Study on the Flexural Strength of Interior Thick Wall-Thick Slab Joints Subjected to Lateral Force Using Finite-Element Analysis

A brand-new structural type, termed thick wall-thick slab structure, has been developed in recent years based on the reinforced concrete wall structure in Japan. This type of structural system can not only maintain high seismic performance, but also provide large interior space and improve the flexibility of the architectural design that is more favored by architects. In the present study, an equivalent cross-sectional area concept in which a coefficient termed the equivalent cross-sectional area ratio is proposed to estimate the flexural strength of the horizontal member of the interior wall-slab joints, which are critical assemblies in the thick wall-thick slab structures. To capture the stress condition of slab flexural reinforcement for calculating the equivalent cross-sectional area ratio, the method of finite-element analysis was employed in this work. The finite-element modeling was calibrated firstly using two isolated interior wall-slab joints from literature and consequently applied to a parametric numerical study. Finally, results from these finite-element analyses are adopted to propose the equivalent cross-sectional area ratio for modifying the current code formula to predict the flexural strength of interior wall-slab joints in TWTS structures subjected to lateral force.

Bone Density, Geometry, and Mass by Peripheral Quantitative Computed Tomography and Bone Turnover Markers in Children with Diabetes Mellitus Type 1.

Background The type 1 diabetes mellitus (T1DM) is a chronic systemic autoimmune-mediated disease characterised by the insulin deficiency and hyperglycaemia. Its deleterious effect on bones concerns not only bone mass, density, and fracture risk but also may involve the linear growth of long bones. Studies on the lower leg in children with T1DM by pQCT have generated conflicting results, and most of the studies published so far focused only on a selected features of the bone. An additional information about growth, modelling, and remodelling processes can be gathered by the bone turnover marker measurement. The objective of the study was to evaluate bone mineral density, mass, and geometry using peripheral quantitative computed tomography as well as bone turnover markers in the patients with type 1 diabetes mellitus. Material and Methods. Bone mineral density, mass, and geometry on the lower leg using peripheral quantitative computed tomography and serum osteocalcin (OC) and carboxyterminal cross-linked telopeptide of type 1 collagen (CTx) were measured in 35 adolescents with T1DM (15 girls) aged 12.3-17.9 yrs. The results were compared to age- and sex-adjusted reference values for healthy controls. Results Both sexes reveal lower than zero Z-scores for lower leg 66% total cortical bone cross-sectional area to muscle cross-sectional area ratio (−0.97 ± 1.02, p = 0.002517 and −0.98 ± 1.40, p = 0.007050, respectively) while tibia 4% trabecular bone density Z-score was lowered in boys (−0.67 ± 1.20, p = 0.02259). In boys in Tanner stage 5 bone mass and dimensions were diminished in comparison to Tanner stages 3 and 4, while in girls, such a phenomenon was not observed. Similarly, bone formation and resorption were decreased in boys but not in girls. Consistently, bone turnover markers correlated positively with bone size, dimensions, and strength in boys only. Conclusions T1DM patients revealed a decreased ratio of cortical bone area/muscle area, reflecting disturbed adaptation of the cortical shaft to the muscle force. When analyzing bone mass and dimensions, boys in Tanner stage 5 diverged from “less-mature” individuals, which may suggest that bone development in these individuals was impaired, affecting all three: mass, size, and strength. Noted in boys, suppressed bone metabolism may result in impairment of bone strength because of inadequate repair of microdamage and accumulation of microfractures.