Battery State of Charge Management for an Electric Vehicle Traction System

This chapter introduces a battery state of charge (SOC) management technique designed for an electric vehicle traction system that incorporates an indirect field-oriented induction motor drive. The primary goal of this technique is to restrict the change in battery SOC from exceeding a maximum limit, by compensating for the motor speed tracking performance. It employs a fuzzy-tuned model predictive controller (FMPC), where a fuzzy logic controller (FLC) adjusts the input weight in the objective function to ensure that the change in battery SOC does not exceed the maximum permitted value while regulating the motor speed. The various components of the EV traction system are thoroughly modeled, and simulations are conducted using MATLAB/Simulink 2018b. The simulation results, carried out using the New European Drive Cycle (NEDC), verify that the technique limits the change in SOC while controlling the motor speed. This approach offers the advantage of maintaining precise control over the battery bank SOC, which distinguishes it from conventional speed regulators

Design and Analysis of Microwave Devices Based on Gap Waveguide Technology

Among state-of-the-art guiding structures, the Ridge Gap Waveguide (RGW) is a promising technology, as it minimizes the losses in high-frequency applications and supports wide operating bandwidth. There is another form of the guiding structures that utilize the idea of the Artificial Magnetic Conductor (AMC) surfaces such as Groove Gap Waveguide (GGWG). It has the same advantages as the RGW in terms of losses, and immunity to leakages without the need for electrical contacts, but with different dispersion characteristics. The RGW supports a quasi-TEM mode while the GGWG supports TE modes as it's a different form of the rectangular waveguide. Therefore, GGWG has high power capability comparable to the standard waveguides. As currently, interest is increasing of millimeter wave and microwave applications, the RGW and GGWG are excellent candidates for these applications due to their low loss. It is quite essential to develop microwave components with superior electrical characteristics for such applications. The anisotropic materials have useful physical properties that can benefit the microwave devices, due to their enormous advantages such as high stability and wide bandwidth in the millimeter wave band. Ferrite is an example of such anisotropic materials. Their properties can be deployed to improve the performance of the millimeter microwave devices in terms of higher stability, wider band, and high power handling. Taking advantages of the above characteristics, the research work in this thesis is focusing on their use for microwave and millimeter wave frequencies. The presented devices are responsible for the feeding of the antenna systems. Moreover, they can be deployed in different applications such as antenna beamforming. In this thesis, the differential phase shifters and the orthomode transducers (OMTs) are realized by different technologies that are suitable for both of the microwave and the millimeter wave bands that serve different applications of the wireless communication systems. The research work done can also be summarized in two parts. The first part starts with the study and investigation of the ferrite material properties and their role in the microwave devices. Then, later providing a new accurate model with mathematical formulas for the differential ferrite phase shifter. Moreover, a new design methodology for those phase shifters is presented. Later, the ferrite is applied in the conventional waveguide, Substrate Integrated Waveguide (SIW), and RGW technologies. In the second part, study, design, and analysis of different types of the orthomode transducers are presented. They are devices responsible for combining and separation of two orthogonal polarizations. The presented OMTs has a compact size with excellent performance. Several OMT types are considered such as the one-fold symmetry, asymmetric, and two-fold symmetry. The first mentioned two OMTs are realized by deploying the waveguide technology, while the two-fold symmetry OMT is based on the GGWG technology. It has the ability to design a feeding network for an array of antennas based on the GGWG technology. Moreover, this OMT is fabricated using 3D printed technology that uses the carbonated plastic material, in which two copper layers are covering all the structure surfaces by electroplating. This fabrication is a new promising technology that is not expensive, lightweight and less complex than traditional machining. However, there are some concerns about power handling and high temperature withstanding. Such problems might have a solution in the future with a more accurate 3D metallic printers

Emergency small- vs large-tube thoracostomy in chest trauma patients

Background: Therapeutic drainage is used to treat pleural disorders such as pneumothorax, hemothorax, empyema, chylothorax, and malignant effusions. This study aimed to conduct a comparative analysis of small (24-26 Fr) versus large (30-32 Fr) tube thoracostomy in terms of the efficacy of drainage due to concerns about obstruction (in the case of hemothorax) or inadequate drainage (in the case of hemothorax, pneumothorax, or hemopneumothorax), pain score, repositioning, and the need for thoracotomy. Methods: This randomized prospective study included 112 chest trauma patients who experienced significant hemothorax, pneumothorax, or a combination of these conditions in a trauma unit (reception, inpatient, or ICU) between December 2021 and December 2022. Patients were randomly divided into two groups. Group I included 56 patients who underwent small (24–26 Fr) tube thoracostomy and 56 patients in Group II, in which a large (30-32 Fr) tube thoracostomy was performed. We investigated the differences between the two groups in terms of pain score, complication rate, duration of tube insertion, and need for another chest tube or thoracotomy. Results: There was no statistically significant difference between the two groups concerning the mode of trauma, chest trauma, or effect of trauma (p= 0.781, 0.622, >0.99, and >0.99, respectively). The two groups had a highly statistically significant difference regarding the pain score (p<0.001). There was no statistically significant difference between the two groups regarding the duration of tube insertion (P<0.001). There were no statistically significant differences between the two groups regarding outcomes (drainage efficacy, tube repositioning, tube replacement, or the need for thoracotomy) (p= 0.315, 0.344, and 0.814, respectively). Conclusion: Increasing the tube size might not affect the efficacy of drainage, the duration of tube insertion, the need for another tube, or the need for thoracotomy. Small (24-26 Fr) tube thoracostomies could also have favorable pain score outcomes

Cardiac Myxomas: A single center experience and ten-years follow up

Background: Cardiac myxoma is a benign tumor that carries the risk of embolization and obstruction of the blood flow. The ideal surgical approach is still debatable. We present our experience in the surgical treatment of cardiac myxomas and its ideal surgical approach.Methods: We retrospectively analyzed the data for all patients who underwent surgical excision of cardiac myxoma at our institution over 11 years starting from January 2006 to December 2016. Descriptive statistics were used to present preoperative, operative and postoperative data and Kaplan Meier curve to plot long-term survival.Results: Twenty-one patients had surgical excision of a primary, single and sporadic cardiac myxoma. Thirteen patients (62 %) were females, and the mean age at operation was 55.2 years (range: 28 – 71 years). The location of myxomas was in the left atrium in 17 patients (81%) and right atrium in 4 patients (19 %). Dyspnea was the main presenting symptom (71.4%) followed by constitutional symptoms (28%), palpitations (23.8%), syncope (14.2%) and stroke (14.2%). A right atrial trans-septal incision was used in 76.5% of left atrial myxoma cases. Five patients had concomitant operative procedures (coronary artery bypass grafting (n=2), tricuspid valve repair (n=1), mitral valve replacement (n=1) and bullectomy (n=1)). Postoperative complications were reported in six patients (28.6%) (supraventricular arrhythmia (n=2), temporary conduction deficit (n=2), pulmonary atelectasis (n=1), and postoperative bleeding (n=1)). Early postoperative mortality occurred in one patient (4.76 %), and there were no late deaths related to myxoma.Conclusion: Surgical treatment of cardiac myxoma is safe with low morbidity and mortality. The right atrial trans-septal incision is the recommended surgical approach

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was USD 92 492 million using approach 1 and USD 73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was USD 95 004 million using approach 1 and USD 75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially.publishedVersio

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

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 &lt; 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

Global economic burden of unmet surgical need for appendicitis

Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population