20 research outputs found
The effects of Visual Stability Index (VSI) on fresh segregation of self consolidating concrete (SCC) using fly ash class C and F
Self-consolidating concrete (SCC) is a concrete technology that is growing in popularity with the precast/prestressed industry and contractors. SCC increases the ease of concrete placement as well as reduces overall cost by requiring less labor and time for a concrete placement. This study is part of the proposed project by Tennessee Department of Transportation (TDOT) carried out by University of Tennessee at Chattanooga (UTC) to develop four new SCC mixtures (two Class P-SCC (precast) and two Class A-SCC (general use), and insure they meet the minimum strength and durability requirement for TDOT Class P and Class A mixtures. The objectives of the study presented in this thesis are to analyze a survey of state Departments of Transportation SCC specifications and requirements and investigate the effect of fly ash class and aggregate size and shape on fresh properties of Class A-SCC. In addition, investigate the relationship between Visual stability index (VSI) and fresh segregation of SCC. Finally, recommend the specifications of fresh performance requirements for the Class A-SCC that the Tennessee Department of Transportation (TDOT) should apply to establish SCC stability and flowability during the production of general concrete elements
An Online Numeral Recognition System Using Improved Structural Features – A Unified Method for Handwritten Arabic and Persian Numerals
With the advances in machine learning techniques, handwritten recognition systems also gained importance. Though digit recognition techniques have been established for online handwritten numerals, an optimized technique that is writer independent is still an open area of research. In this paper, we propose an enhanced unified method for the recognition of handwritten Arabic and Persian numerals using improved structural features. A total of 37 structural based features are extracted and Random Forest classifier is used to classify the numerals based on the extracted features. The results of the proposed approach are compared with other classifiers including Support Vector Machine (SVM), Multilayer Perceptron (MLP) and K-Nearest Neighbors (KNN). Four different well-known Arabic and Persian databases are used to validate the proposed method. The obtained average 96.15% accuracy in recognition of handwritten digits shows that the proposed method is more efficient and produces better results as compared to other techniques
Maternal and perinatal outcomes of dengue in PortSudan, Eastern Sudan
<p>Abstract</p> <p>Aim</p> <p>To investigate maternal and perinatal outcomes (maternal death, preterm delivery, low birth weight and perinatal mortality) of dengue at PortSudan and Elmawani hospitals in the eastern Sudan.</p> <p>Method</p> <p>This was a retrospective Cohort study where medical files of women with dengue were reviewed.</p> <p>Results</p> <p>There were 10820 deliveries and 78 (0.7%) pregnant women with confirmed dengue IgM serology at the mean (SD) gestational age of 29.4(8.2) weeks. While the majority of these women had dengue fever (46, 58.9%), hemorrhagic fever and dengue shock syndrome were the presentations in 18 (23.0%) and 12, (15.3%) of these women, respectively. There were 17(21.7%) maternal deaths. Fourteen (17.9%) of these 78 women had preterm deliveries and 19 (24.3%) neonates were admitted to neonatal intensive care unit. Nineteen (24.3%) women gave birth to low birth weight babies. There were seven (8.9%) perinatal deaths. Eight (10.2%) patients delivered by caesarean section due to various obstetrical indications.</p> <p>Conclusion</p> <p>Thus dengue has poor maternal and perinatal outcomes in this setting. Preventive measures against dengue should be employed in the region, and more research on dengue during pregnancy is needed.</p
Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries
Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
Microscopic and Image Processing Characterization of Aggregates to Predict ASR Expansion Potential of Concrete
Preventing ASR occurrence in new concrete structures requires reliable and quick methods to identify reactive aggregates and to evaluate proper mitigation alternatives. The current accelerated mortar-bar expansion tests (ASTM C 1260 or ASTM C1567) and the concrete prism expansion test (ASTM C 1293) have been reported to have several limitations. Assessment of the extend of ASR damage in existing affected structures requires more understanding on how ASR expansion and damage develop in field conditions such as under confinements and under relatively slow rate of ASR reaction.
The significance of ASR expansion rate and bi-axial restrain on concrete degradation has been investigated. Results show that degradation of mechanical properties was significantly influenced by the rate of ASR expansion and slightly affected by confinement. Specifically, slow rate of ASR expansion was beneficial in limiting concrete degradation while the direction of restraint influenced the crack orientation.
A quantitative petrographic characterization was conducted to predict the ASR reactivity of Tennessee aggregates, mainly granite and limestone aggregates. The reactivity of limestone aggregates is strongly related to the amount of SiO2. The silica content of 26 limestones shows a strong correlation with the expansion in the concrete prism test. The early and highly expansive limestones are characterized by a high clay/ mica content (\u3e 5%). The reactivity of limestone aggregates is mainly caused by crypto/microcrystalline quartz, chert, and finely disseminated silica in carbonate and clay/mica matrices.
The reactivity of granite aggregates is related to the microstructural features of the minerals, namely the quartz grain size distribution and quartz grain boundaries. These features can be quantified using image processing of combined polarized microscope images. The grain size of quartz can only provide an indication of aggregate reactivity. The amount and distribution of quartz need to be considered to confirm aggregate reactivity and the potential expansion of an aggregate. Results indicated that an increase in the amount of quartz \u3c 60 µm shows a corresponding increase in the ASR expansion. Granite aggregates with more than 7% of quartz \u3c 60 µm exceed the expansion limits on both ASTM C1293 and ASTM C1260
Effect of Rhizobium and Bacillus strains on the growth, symbiotic properties and nitrogen and phosphorus content of lablab bean (Lablab purpureus L.)
Effect of Rhizobium and Bacillus strains on the growth, symbiotic properties and nitrogen and phosphorus content of lablab bean (Lablab purpureus L.) ABSTRACT Two field experiments were carried out at two different locations viz :EL-Hudaiba and Shambat (Sudan) to study the effect of biofertilization with Rhizobium and BMP on the symbiotic properties and shoot nitrogen and phosphorus content of lablab bean. Randomized complete block design was adopted in the two experimental sites in a factorial combination of 5 Rhizobia x 3 BMP x 4 replications x 2 times of sampling. Four Rhizobium strains were used throughout this study, these are cowpea strain, ENRRI 16A, USDA 5019 and TAL 169. BMP in the form of phosphobacterin and phosphorin were used. Rhizobium and BMP inoculation individually significantly ((P#0.05) increased nodulation, shoot, root and nodule dry weight per plant and phosphorus and nitrogen content of the shoot. In all parameters tested, in the two locations, cowpea strain was superior to other strains followed by strain ENRRI 16A, TAL 169 and USDA 5019 respectively. Phosphobacterin overweighed phosphorin in the two locations for the tested parameters. Co-inoculation with Rhizobium and BMP compared to individual inoculation and uninoculated control significantly ((P#0.05) increased the parameters under investigation. cowpea strain and phosphobacterin co-inoculation was the best combination in the two locations. The study revealed the need for biological fertilizers with compatible effective strains to compensate the chemical fertilizers
Low-Complexity Angle-Domain MIMO NOMA System with partial channel state information for MmWave Communications *
In millimeter-wave communication, digital beamsteering (DBS), only based on the user direction, is a promising angle-domain multi-antenna technique to mitigate the severe path loss and multiuser interference, with low-complexity and partial channel state information (CSI). In this paper, we design a power-domain non-orthogonal multiple access (NOMA) scheme that enhances the DBS performance trading-off complexity , energy-consumption and capacity performance. In particular, we propose a user-clustering algorithm to pair users, based on a geometric-interference metric, so that the inter-user interference is reduced. Afterward, based on a fixed inter-cluster power allocation, we derive analytically a sub-optimal intra-cluster power allocation optimization problem to maximize the network throughput. To address the issue of partial CSI, we rewrite the aforementioned optimization problem, by relying only on the user direction. Performance evaluation of the proposed schemes is developed in rural environment, based on the New York University millimeter-wave simulator. The obtained results demonstrate that the proposed low-complexity NOMA-DBS schemes with either full-or partial-CSI achieve significant performance improvement over the classical DBS, in terms of spectral-and energy-efficiencies (up to 26.8% bps/Hz rate gain for 45 users using the proposed scheme with partial CSI).0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 DBS UPA M V =5 DBS UPA M V =4 DBS UPA M V =