Behaviour of Grey Cast Iron Under Combined Bending and Tension

This paper deals with the strength of grey cast iron components subjected to combined bending and tension, this case of loading being met in C-frames and clamps, crane hooks and various eccentrically—loaded protruding machine parts. Specimens of rectangular as well as trapezoidal sections, made of flake graphite cast iron, were tested under conditions of eccentric loading. With due consideration of non-linearities and inequalities in stress-strain relations in tension and compression, stress distribution for these sections was obtained from strain measurements. The ratio of bending to tensile stress components is herein shown to play a significant role in locating the neutral plane and in identifying the dominating failure stress. The value 2, for this ratio, is shown to draw some demarkation border between the two modes of fracture encountered in the tests. The apparent superiority of bending strength over tensile strength is herein attributed to the widely differing stress-strain relations in tension and compression

Magnetostatic surface waves on left-handed materials (LHM)

The nonlinear characteristics of magnetostatic surface waves at microwave frequencies in a layered structure of left-handed material film and a semi-infinite linear ferrite substrate have been investigated. The general dispersion relation is derived and analyzed numerically. It is found that it has two solutions for ω (k), one represents a physical solution and other unacceptable. The effects of the applied external magnetic field around the proposed region have also been examined

Trends of complications and innovative techniques' utilization for colectomies in the United States.

Despite an increasing trend towards utilization of minimally invasive approaches (MIS), results regarding their safety profile are contradictory. All patients who underwent elective colectomy for any underlying disease with an identifiable operative approach available from the targeted colectomy files of the ACS-NSQIP PUFs 2013 to 2018 were included. The trend of utilization and complication rates of the different operative approaches (open, laparoscopic, robotic) were assessed during the inclusion period. Furthermore, overall, surgical, and medical complications were compared between the three approaches. The study cohort included 78,987 patients. Of them, 12,335 (15.6%) patients underwent open, 57,874 (73.3%) laparoscopic, and 8,778 (11.1%) robotic surgery. There was an increasing trend towards the utilization of robotic surgery (2.5% increase per year) at the expense of the other approaches. With the increasing trend toward the utilization of the robotic approach, a decreasing trend in overall and surgical complications and length of stay was observed. After adjusting for the baseline confounders, robotic surgery was associated with shorter length of stay, lower rate of overall (OR 0.397; p < 0.05 compared to open and OR: 0.763; p < 0.05 compared to laparoscopy) and surgical complications (OR: 0.464; p < 0.05 compared to open and OR: 0.734; p < 0.05 compared to laparoscopy). This study revealed an increasing trend toward the utilization of MIS for elective colectomy in the US. Robotic surgery was associated with a decreasing trend in overall and surgical morbidity and length of stay

Heat Treated NiP–SiC Composite Coatings: Elaboration and Tribocorrosion Behaviour in NaCl Solution

Tribocorrosion behaviour of heat-treated NiP and NiP–SiC composite coatings was investigated in a 0.6 M NaCl solution. The tribocorrosion tests were performed in a linear sliding tribometer with an electrochemical cell interface. It was analyzed the influence of SiC particles dispersion in the NiP matrix on current density developed, on coefficient of friction and on wear volume loss. The results showed that NiP–SiC composite coatings had a lower wear volume loss compared to NiP coatings. However, the incorporation of SiC particles into the metallic matrix affects the current density developed by the system during the tribocorrosion test. It was verified that not only the volume of co-deposited particles (SiC vol.%) but also the number of SiC particles per coating area unit (and consequently the SiC particles size) have made influence on the tribocorrosion behaviour of NiP–SiC composite coatings

A PDRMIP multi-model study on the impacts of regional aerosol forcings on global and regional precipitation

Atmospheric aerosols such as sulfate and black carbon (BC) generate inhomogeneous radiative forcing and can affect precipitation in distinct ways compared to greenhouse gases (GHGs). Their regional effects on the atmospheric energy budget and circulation can be important for understanding and predicting global and regional precipitation changes, which act on top of the background GHG-induced hydrological changes. Under the framework of the Precipitation Driver Response Model Inter-comparison Project (PDRMIP), multiple models were used for the first time to simulate the influence of regional (Asian and European) sulfate and BC forcing on global and regional precipitation. The results show that, as in the case of global aerosol forcing, the global fast precipitation response to regional aerosol forcing scales with global atmospheric absorption, and the slow precipitation response scales with global surface temperature response. Asian sulphate aerosols appear to be a stronger driver of global temperature and precipitation change compared to European aerosols, but when the responses are normalised by unit radiative forcing or by aerosol burden change, the picture reverses, with European aerosols being more efficient in driving global change. The global apparent hydrological sensitivities of these regional forcing experiments are again consistent with those for corresponding global aerosol forcings found in the literature. However, the regional responses and regional apparent hydrological sensitivities do not align with the corresponding global values. Through a holistic approach involving analysis of the energy budget combined with exploring changes in atmospheric dynamics, we provide a framework for explaining the global and regional precipitation responses to regional aerosol forcing

When global norms meet local politics : localising transparency in extractive industries governance

Processes of norm localisation play a crucial role in shaping the extent to which global governance norms are institutionalised at national and sub‐national levels. This article explores the politics of norm localisation through an empirical investigation of how global norms of “transparency” were localised in sub‐national processes of extractive industry governance in Bojonegoro, Indonesia. Previous theories of localisation have emphasised “constructivist” dynamics through which patterns of norm localisation are shaped decisively by efforts to build normative or cognitive congruence with local ideas and identities. In contrast, the mix of a newly democratised environment, the persistent power of corporatist elite networks and a populist style of local politics prevailing in Bojonegoro have diminished the significance of such constructivist dynamics as a basis for explaining varied patterns of norm localisation. Instead, patterns of norm localisation have depended crucially on the capacity of local political leaders to harness global governance norms instrumentally as a basis for consolidating and strengthening their own local power base. These findings have important implications for both theoretical and practical understandings of how global norm localisation processes vary in response to the contrasting political contexts in which global governance norms targeting the extractive sector are implemented

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700