Reduction of pollutants emissions on si engines : accomplishments with efficiency increase

This paper presents an experimental study aiming to identify the means to minimize the reduction of the overall performance of a gasoline engine when employing the Exhaust- Gas Recirculation (EGR) technique that reduces NOx emissions. The increase of the compression ratio and turbocharging was evaluated as a mean to recover the original performance. The formation of pollutants and the engine performance were verified at full and partial loads. The results show that the combination of exhaust gas recirculation with turbocharger or through an increase of the compression ratio enhance the relation between the engine performance and the emission of NO. However, the turbocharger seemed to be more sensitive to the negative effects of the EGR technology

Assessing the crashworthiness of a vehicle seat for rear and frontal impacts

A vehicle seat represents an automotive passive system because it limits the damage caused to passengers in the events of an accident or a crash. This way, the present work intends to evaluate the safety of an anchorage mechanism of a frontal vehicle driver seat considering two hazardous situations rear and frontal impacts. Performing a nonlinear FE in static and transient analyses provide the stress distribution in the main components of the mechanism, such as the inner track, the lock device and the bolts using Ansys®. Regulation Nº 17 from Un/ECE regulates the acceleration levels predicted in a crash test and therefore applied in the simulation. In addition, departing from a crash of 5g a fatigue analysis is carried out. From this particular analysis, it becomes possible to evaluate the actual safety of the vehicle seat after a minor crash

Desempenho na barra de tração de um conjunto trator-semeadora / Performance in the drawbar of a tractor-sower set

Para que se tenha máximo aproveitamento da energia gerada no motor e transmitida para barra de tração, faz se necessários estudos sobre diversas condições de carga na barra de tração. Objetivou-se com esse trabalho avaliar o desempenho na barra de tração de um conjunto trator-semeador em função do preparo do solo e escalonamentos de marchas. Foi utilizada uma semeadora-adubadora da marca Tatu Marchesan, modelo SDA³ de fluxo contínuo de 15 linhas com espaçamento de 0,158 m para semeadura de arroz, tracionada por um trator 4x2 TDA. O delineamento experimental foi em blocos casualizados em arranjo fatorial 2x3 com 4 repetições. Os tratamentos foram constituídos por dois preparos do solo (preparo com arado + grade e escarificador), e três escalonamentos de marchas L3T, L3C e L4C, correspondendo as velocidades de 4,56; 5,71 e 7,63 km h-1, respectivamente. Foram calculados a velocidade de deslocamento, força e potência na barra de tração. Os dados foram submetidos à análise de variância e quando significativos foi aplicado o teste de Tukey a 5% de probabilidade. O melhor desempenho na barra de tração foi obtido no solo preparado com o uso de escarificado. A marcha L4C (7,63 km h-1) foi a que apresentou maior exigência de potência na barra de tração no processo de semeadura

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

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

Evaluation of PETG mechanical behavior for application in vehicle protection

During the last decades, highway authorities and motor vehicle manufacturers attempt to reduce the statistics of accidents in the world. However, the number of road traffic deaths continues to rise steadily, reaching 1.35 million in 2016. One of the accidents present in this statistic is the side-impact. Several researchers have dedicated themselves to develop passive safety devices that meet the demand for protection of the occupants in the event of collisions. Thin-walled energy absorbers are currently used to protect vehicle passengers against the harmful consequences of frontal collisions; though, the idea of using them against side impacts has not been appropriately explored. This work aims to present the experimental tests performed on the material PETG (polyethylene terephthalate glycol), a semicrystaline thermoplastic. The ASTM C365 covers the determination of compressive strength and modulus of sandwich cores, under quasi-static compressive loads. ASTM D638 reports the procedure to determine the tensile properties. The results draw that the material could have a significant contribution to resisting the impact, whether applied as a core of a thin-walled square mild-steel tube

Development of a test device for roof crush in real and reduced scale

Estatísticas mundiais mostram que capotamentos podem causar vítimas fatais ou ferimentos graves aos ocupantes do carro. O teste de esmagamento do teto estabelecido no FMVSS 216a permite avaliar a integridade estrutural da cabine do veículo. O objetivo principal é evitar mortes e ferimentos devido ao esmagamento do teto no compartimento do ocupante em colisões de capotamento. O teste considera que uma força de certa magnitude é aplicada de maneira quase estática em um lado do teto. Essa força representa a força envolvida no contato teto/solo durante a capotagem. O trabalho tem como objetivo apresentar o desenvolvimento de um dispositivo de teste que pretende avaliar a resistência das estruturas do teto de veículos respeitando os requisitos de força e intrusão. No entanto, este dispositivo é adequado para testar a resistência dos tetos em escalas reais e reduzidas. Além disso, para realizar o teste não é necessário todo o veículo, mas apenas seu teto com colunas A, B e C rigidamente fixadas em um sistema de suportes. Este sistema é equivalente ao apresentado na norma. Nessas condições, a superfície necessária para o teste e o custo são mais acessíveis e simples de operar. Observe que o teste em escala reduzida leva em consideração a similaridade na geometria e cinemática com base na perspectiva da teoria da similaridade.World statistics show that rollovers can cause fatal victims or severe injuries to the car occupants. The roof crush test established in the FMVSS 216a allows assessing the structural integrity of the vehicle's cabin. The primary purpose is to avoid deaths and injuries due to the crushing of the roof into the occupant compartment in rollover crashes. The test considers that a force of a certain magnitude is applied in a quasi-static manner to one side of the roof. Such a force represents the force involved in the contact roof/ground during the rollover. The work aims to present the development of a test device that intend to evaluate the strength of vehicle roof structures respecting the requirements of force and intrusion. However, this device is suitable to test roofs’ strength in real and reduced scales. In addition, to proceed the test the entire vehicle is not necessary, but only its roof with A, B, and C columns rigidly attached in a system of supports. This system is equivalent to the one presented in the standard. Under these conditions, the surface required to the test, and the cost are more accessible and simple to operate. Notice that the reduced scale test takes into account the similarity in geometry and kinematic based on the perspective of the theory of similarity