Determination of the Change in Electrical Conductivity of Single, Bimetallic and Trimetallic Cylindrical Billets with Plastic Deformation Induced by Upsetting Process

In this study, measurement of the effect of singular, bimetallic and multimetallic materials exposed to cold plastic deformation on electrical conductivity properties was investigated. The main subject of this research is plastic deformation occurring in the upsetting process and changing the conductivity properties of the parts. In the experiments, steel, aluminium, copper, brass, bimetallic and multimetallic materials designed with different combinations of these materials were used as test materials. Experimental upsetting tests were performed as a height reduction ratio 10%, 20% and 30%. The electrical conductivity measurement results of the deformed samples were obtained with a conductivity measuring device. The results obtained from the experiments are presented in graphs with electrical conductivity axis that change due to deformation. As a result of the experiments and measurements, it was concluded that the electrical conductivity of the deformed materials generally decreased slightly due to the plastic deformation of the deformed materials, and the bimetallic and multimetallic materials were similar to the properties of the majority material

Leakage tests reduce the frequency of biliary fistulas following hydatid liver cyst surgery

BACKGROUND AND AIM: Biliary fistulas are the most common morbidity (8.2-26%) following hydatid liver surgery. The aim of our study was to reduce the incidence of postoperative biliary fistulas after the suturing of cystobiliary communications by applying a bile leakage test. PATIENTS AND METHODS: A total of 133 hydatid liver cysts from 93 patients were divided into two groups, according to whether the test was performed. Tests were performed on 56 cysts from 34 patients, and the remaining 77 cysts from 59 patients were treated without the test. In both groups, all visible biliary orifices in the cysts were suture ligated, and drains were placed in all cysts. The visibility of the biliary orifices and postoperative biliary drainage through the drains were recorded. Patients in both groups were also compared with respect to the number of days living with the drains, the length of the hospital stay, and secondary interventions related to biliary complications. RESULTS: Biliary orifices were more visible in the tested cysts (13% vs. 48%; P <0.001). Fewer biliary complications occurred in the tested patients (8.8% vs. 27.7%, P = 0.033). The mean drain removal time (4.1±3.3 days vs. 6.8±8.9 days, P<0.05) and the length of the hospital stay (6.7±2.7 days vs. 9.7±6.3 days, P,0.01) were shorter for the tested patients. None of the patients in the test group required postoperative Endoscopic retrograde cholangiopancreaticography (ERCP) or nasobiliary drainage (0.0% vs. 8.4%, P = 0.09). There were no long-term biliary complications for either group after three years of follow-up. CONCLUSIONS: Identification of biliary orifices with a bile leakage test and the suturing of cystobiliary communications significantly reduced postoperative biliary complications following hydatid liver surgery

Effect of receiver shape and volume on the Alzheimer disease for molecular communication via diffusion

The work of I. Isik and M. E. Tagluk was supported by the Inonu University Project of Scientific Research Unit (BAP) under the project number FBA-2018-1013. The authors thank HP Turkey section for providing a powerful computer for computational tasks in this study. The work of H.B. Yilmaz is supported by the Scientific and Technical Research Council of Turkey (TUBITAK) under grant no. 118C274. The work of I. Demirkol was supported by the Spanish Government, MINECO, through project RYC-2013-13029Peer ReviewedPostprint (published version

Electrically tunable radiative cooling performance of a photonic structure with thermal infrared applications

Thermal infrared (IR) radiation has attracted considerable attention due to its applications ranging from radiative cooling to thermal management. In this paper, we design a multi-band graphene-based metamaterial absorber compatible with infrared applications and radiative cooling performance. The proposed structure consists of the single-sized metal-insulator-metal (MIM) grating deposited on metal/insulator substrate and single-layer graphene. The system realizes a broadband perfect absorption ranging from 940 nm to 1498 nm and a narrowband perfect absorption at the resonance wavelength of 5800 nm. Meanwhile, the absorptivity of the structure is suppressed within the mid-wave infrared (MWIR) and long-wave infrared (LWIR) ranges. Furthermore, to demonstrate the tunability of the structure, an external voltage gate is applied to the single-layer graphene. It is shown that, by varying the chemical potential of graphene layer from 0 eV to 1 eV , the absorption resonances at the mid-infrared (MIR) range can shift toward the shorter wavelengths. It is also observed that the structure can possess an average net cooling power over 18 at the ambient temperature, when is varied from 0 eV to 1 eV. Finally, we investigate the overall performances of the structure as a function of temperature to realize thermal infrared applications.Comment: 11 pages, 6 figure

Determination of permanent deformation of flexible pavements using finite element model

Nevezani zrnati materijal koji se koristi u savitljivim kolničkim konstrukcijama ponaša se elastoplastično pod utjecajem ponavljanih prometnih opterećenja. Trajne deformacije koje se javljaju na površini kolnika uslijed prometnog opterećenja jedan su od osnovnih problema koji negativno utječu na ponašanje kolničkih konstrukcija. Zbog toga su u novije vrijeme razvijeni brojni modeli za analizu trajnih deformacija, tj. za izračunavanje pojave kolotraga na kolnicima. Većina istraživanja koja se bave tim pitanjem temelje se na provedbi dinamičkih troosnih ispitivanja. U ovom je istraživanju deformabilnost nevezanih zrnatih materijala određena ispitivanjem prema metodi rezonantnog stupca. Također, umjesto određivanja ukupnih trajnih deformacija zbrajanjem izračunanih deformacija pojedinačnih slojeva kolnika, u ovom se radu na četiri različita tipa kolničkih konstrukcija provode dinamičke dvodimenzionalne osnosimetrične analize metodom konačnih elemenata kako bi se predvidjela ukupna trajna deformacija koja se javlja na površini kolnika nakon određenog broja ciklusa opterećenja. Nevezani slojevi za prvi modelirani tip kolničke konstrukcije sastoje se od prirodnog agregata. Nevezani nosivi sloj i/ili tamponski sloj preostalih triju kolničkih konstrukcija sastoji se od otpadnog materijala čelične zgure. Odnos trajnih deformacija i broja ciklusa opterećenja za sva četiri tipa kolničkih konstrukcija prikazan je na polulogaritamskim dijagramima. Za svaki je analizirani tip kolničke konstrukcije prikazana jednadžba trajnih deformacija.The unbound granular material used in flexible road pavements exhibits an elastoplastic behaviour under repetitive traffic loads. Permanent deformation occurring on pavement surface under traffic load is one of the main road pavement problems affecting road performance. Therefore, many permanent deformation models for calculating road pavement rutting have recently been developed by researchers. Most of these studies involve performance of dynamic triaxial tests. In this study, deformation characteristics of unbound granular materials are determined using the resonant column test. Then, instead of determining the total permanent deformation by summing up the calculated permanent deformations obtained in each pavement layer, dynamic 2D axisymmetric finite element analyses are performed for four different pavement cross sections to predict the total permanent deformation occurring on pavement surface under certain load cycles. The first modelled cross section of unbound granular material consists of natural aggregate. The base and/or subbase of remaining three cross sections consists of steel slag waste material. The permanent deformation versus load cycle is presented for four multi-layer road cross sections using semi logarithmic graphs. Finally, the permanent deformation model equation is developed for each pavement cross section using their fitting curves

world multidisciplinary earth sciences symposium wmess 2017

Preface Dedicated volume of IOP conference series journal IOP Earth and Environmental Sciences contains the papers presented in the third "World Multidisciplinary Earth Sciences Symposium", which was held in Hotel Duo in the city of romance Prague (Czech Republic) during 11-15 September 2017. The World Multidisciplinary Earth Sciences Symposium (WMESS) has become a popular international event with participants from more than 50 countries, where experienced scientists, experts, university teachers and young researchers have the opportunity to discuss topics related to geosciences. Traditionally, this year's symposium had a very interesting scientific program supplemented with rich social events and geological field trip to the old mining city Přibram

Plasticity in dendroclimatic response across the distribution range of Aleppo pine (Pinus halepensis)

We investigated the variability of the climate-growth relationship of Aleppo pine across its distribution range in the Mediterranean Basin. We constructed a network of tree-ring index chronologies from 63 sites across the region. Correlation function analysis identified the relationships of tree-ring index to climate factors for each site. We also estimated the dominant climatic gradients of the region using principal component analysis of monthly, seasonal, and annual mean temperature and total precipitation from 1,068 climatic gridpoints. Variation in ring width index was primarily related to precipitation and secondarily to temperature. However, we found that the dendroclimatic relationship depended on the position of the site along the climatic gradient. In the southern part of the distribution range, where temperature was generally higher and precipitation lower than the regional average, reduced growth was also associated with warm and dry conditions. In the northern part, where the average temperature was lower and the precipitation more abundant than the regional average, reduced growth was associated with cool conditions. Thus, our study highlights the substantial plasticity of Aleppo pine in response to different climatic conditions. These results do not resolve the source of response variability as being due to either genetic variation in provenance, to phenotypic plasticity, or a combination of factors. However, as current growth responses to inter-annual climate variability vary spatially across existing climate gradients, future climate-growth relationships will also likely be determined by differential adaptation and/or acclimation responses to spatial climatic variation. The contribution of local adaptation and/or phenotypic plasticity across populations to the persistence of species under global warming could be decisive for prediction of climate change impacts across populations. In this sense, a more complex forest dynamics modeling approach that includes the contribution of genetic variation and phenotypic plasticity can improve the reliability of the ecological inferences derived from the climate-growth relationships.This work was partially supported by Spanish Ministry of Education and Science co-funded by FEDER program (CGL2012-31668), the European Union and the National Ministry of Education and Religion of Greece (EPEAEK- Environment – Archimedes), the Slovenian Research Agency (program P4-0015), and the USDA Forest Service. The cooperation among international partners was supported by the COST Action FP1106, STREeSS

Effect of the COVID-19 pandemic on surgery for indeterminate thyroid nodules (THYCOVID): a retrospective, international, multicentre, cross-sectional study

Background Since its outbreak in early 2020, the COVID-19 pandemic has diverted resources from non-urgent and elective procedures, leading to diagnosis and treatment delays, with an increased number of neoplasms at advanced stages worldwide. The aims of this study were to quantify the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic; and to evaluate whether delays in surgery led to an increased occurrence of aggressive tumours.Methods In this retrospective, international, cross-sectional study, centres were invited to participate in June 22, 2022; each centre joining the study was asked to provide data from medical records on all surgical thyroidectomies consecutively performed from Jan 1, 2019, to Dec 31, 2021. Patients with indeterminate thyroid nodules were divided into three groups according to when they underwent surgery: from Jan 1, 2019, to Feb 29, 2020 (global prepandemic phase), from March 1, 2020, to May 31, 2021 (pandemic escalation phase), and from June 1 to Dec 31, 2021 (pandemic decrease phase). The main outcomes were, for each phase, the number of surgeries for indeterminate thyroid nodules, and in patients with a postoperative diagnosis of thyroid cancers, the occurrence of tumours larger than 10 mm, extrathyroidal extension, lymph node metastases, vascular invasion, distant metastases, and tumours at high risk of structural disease recurrence. Univariate analysis was used to compare the probability of aggressive thyroid features between the first and third study phases. The study was registered on ClinicalTrials.gov, NCT05178186.Findings Data from 157 centres (n=49 countries) on 87 467 patients who underwent surgery for benign and malignant thyroid disease were collected, of whom 22 974 patients (18 052 [78 center dot 6%] female patients and 4922 [21 center dot 4%] male patients) received surgery for indeterminate thyroid nodules. We observed a significant reduction in surgery for indeterminate thyroid nodules during the pandemic escalation phase (median monthly surgeries per centre, 1 center dot 4 [IQR 0 center dot 6-3 center dot 4]) compared with the prepandemic phase (2 center dot 0 [0 center dot 9-3 center dot 7]; p&lt;0 center dot 0001) and pandemic decrease phase (2 center dot 3 [1 center dot 0-5 center dot 0]; p&lt;0 center dot 0001). Compared with the prepandemic phase, in the pandemic decrease phase we observed an increased occurrence of thyroid tumours larger than 10 mm (2554 [69 center dot 0%] of 3704 vs 1515 [71 center dot 5%] of 2119; OR 1 center dot 1 [95% CI 1 center dot 0-1 center dot 3]; p=0 center dot 042), lymph node metastases (343 [9 center dot 3%] vs 264 [12 center dot 5%]; OR 1 center dot 4 [1 center dot 2-1 center dot 7]; p=0 center dot 0001), and tumours at high risk of structural disease recurrence (203 [5 center dot 7%] of 3584 vs 155 [7 center dot 7%] of 2006; OR 1 center dot 4 [1 center dot 1-1 center dot 7]; p=0 center dot 0039).Interpretation Our study suggests that the reduction in surgical activity for indeterminate thyroid nodules during the COVID-19 pandemic period could have led to an increased occurrence of aggressive thyroid tumours. However, other compelling hypotheses, including increased selection of patients with aggressive malignancies during this period, should be considered. We suggest that surgery for indeterminate thyroid nodules should no longer be postponed even in future instances of pandemic escalation.Funding None.Copyright (c) 2023 Published by Elsevier Ltd. All rights reserved

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p&lt;0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p&lt;0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

Prospective Observational Study on acute Appendicitis Worldwide (POSAW)

Background: Acute appendicitis (AA) is the most common surgical disease, and appendectomy is the treatment of choice in the majority of cases. A correct diagnosis is key for decreasing the negative appendectomy rate. The management can become difficult in case of complicated appendicitis. The aim of this study is to describe the worldwide clinical and diagnostic work-up and management of AA in surgical departments.Methods: This prospective multicenter observational study was performed in 116 worldwide surgical departments from 44 countries over a 6-month period (April 1, 2016-September 30, 2016). All consecutive patients admitted to surgical departments with a clinical diagnosis of AA were included in the study.Results: A total of 4282 patients were enrolled in the POSAW study, 1928 (45%) women and 2354 (55%) men, with a median age of 29 years. Nine hundred and seven (21.2%) patients underwent an abdominal CT scan, 1856 (43.3%) patients an US, and 285 (6.7%) patients both CT scan and US. A total of 4097 (95.7%) patients underwent surgery; 1809 (42.2%) underwent open appendectomy and 2215 (51.7%) had laparoscopic appendectomy. One hundred eighty-five (4.3%) patients were managed conservatively. Major complications occurred in 199 patients (4.6%). The overall mortality rate was 0.28%.Conclusions: The results of the present study confirm the clinical value of imaging techniques and prognostic scores. Appendectomy remains the most effective treatment of acute appendicitis. Mortality rate is low.</p