Small-Scale Electric Vehicle DC-DC Converter for Nano-Grids Applications

Have you ever wondered what it would be like to have a self-sustained charging system that does not cost you any money on your electric bill? Electric car owners know that even though their cars do not require gasoline to run, they will require electricity and like everyone else that is tied to the grid will have to pay a price per kilowatt hour that is determined by their utility company. With gasoline prices falling somewhat in the past year the hype of electric vehicles has been somewhat less but who knows what the oil market is going to be like in the future, so why not be prepared. Our paper involves implementing an electric vehicle charging station that uses harvested energy from the sun

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

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

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 variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

Petrography and geochemistry of a limestone-shale sequence with early and late lithification: the Middle Purbeck of Dorset, England

The Middle Purbeck Group (Upper Jurassic-Lower Cretaceous) consists predominantly of limestones and shales of shallow, brackish-water origins. The type-section, Durlston Bay, was investigated and correlations made with other exposures. Samples were studiedwerepetrographically, examined by X.R.D., and 200 of these analysed for 28 elements mainly by X.R.S. Porosities and heavy minerals were studied.The limestones, the &quot;Purbeck Stone&quot;, are mostly bivalve biosparrudites. Bivalve biomicrudites, ostracod hiomicrites and charophyte biomierites also occur. The micrite was calcite mud, often argillaceous: most bivalves were aragonite and this is unchanged in thin shell beds within shales. Partial dissolution has led to precipitation -of fibrous calcite or 'beef. Porosities of biosparrudites increase with increase in aragonite, organic carbon and clay. Calcitized minor evaporites were discovered; calciostrontianite is reported.Chemistry of the limestones is mostly controlled by clay content and by extent of diagenesis. Sparry calcite contains less Mg than micrite. Some migration of Ni, Fe, Zn,S and organic matter from shales into aragonitic beds has occurred. Manganese contents, however, have apparently undergone little change during aragonite-calcite inversion.The shales consist of illite with montmorillonite. Kaolinite occurs above the Cinder Beds as do the heavy minerals kyanite and staurolite. The shales have chemical composition similar to the world average. Rubidium, Ba, Sr and Pb substitute for potassium. Zinc, Fe, Ni, Mn, P and organic carbon are relatively enriched in the calcareous shales. Sodium occurs in calcite. The clays have been derived from older marine sediments and there seemsu9W4rdsto have been a progressive increase in sedimentation rate probably due to increase in rainfall. Lithification of the biosparrudites, the most common limestones, took place in two major stages. Some were lithified early in vadose conditions. These are uncompacted. and occur as thick beds, occasionally with dinosaur footprints. Most biosparrudites, however, were compacted first and then lithified at a late stage. These, which retain more Sr, and organic matter, occur as thinner beds intercalated in shale sequences. Many characteristics, both chemical and petrographic, of these limestone types are detailed here and criteria given for their recognition.</p

Special Purpose Power Electronics Converters for Nano-Grids and Smart Homes Applications

A Nano-grid is a model version of a smart grid with the ability to function as separate power generator. The power electronics converters are playing very important roles in smart homes. So this paper proposes three important converters as the following: Single-Input Multi-Outputs (SIMO) DC-DC Converter, Multi-Inputs Multi-Outputs Converter (MIMO) and Multi-Level Cascaded Inverter (MLCI) Design, Simulation and Implementation. A DC-DC converter is designed effectively and precisely to suit its function in a Nano-grid. The converter is a single-input-multi-output converter (SIMO) which is taking one dc voltage from alternative energy sources like solar photovoltaic panel and applying it to two dc output voltages. This boost converter takes the input and increases its voltages level, leading to the outputs respectively based on the customer’ needs. This single input- multi output converter is designed, simulated and tested using MATLAB/SIMULINK. The input and output characteristic are well depicted in figures form. The Multi-Input-Multi-Output (MIMO) converter, in this work, is a type of switch-mode power supply. The alternative power supplies are in many different operating modes. Finding the right operating mode is key to the MIMO converter fulfilling the needs of design. Simulation and experimental results for rectification, conversion modes are presented with the switching criteria and control characteristics. The modeling, design and simulation are done with the aid of multi-sim software and Simulink. The implementation is done using printed board, power diodes and MOSFETs. Finally, this paper proposes design, modeling and implementation of a multi-level cascaded inverter for a single-phase connected photovoltaic system. The cascaded inverter consists of two full bridge topologies and AC outputs in series. Each bridge has the ability to produce three different voltage outputs. In this work, a single level, three level, and nine levels are proposed using MATLAB/Simulink with circuit implementations. The proposed configuration reduces the complexity in design and modularity when compared to conventional method which also provides reduced switching losses and harmonics