Hybrid electric vehicle fuel minimization by DC-DC converter dual-phase-shift control

The paper introduces an advanced DC-link variable voltage control methodology that improves significantly the fuel economy of series Hybrid Electric Vehicles (HEVs). The DC-link connects a rectifier, a Dual Active Bridge (DAB) DC-DC converter and an inverter, interfacing respectively the two sources and the load in a series HEV powertrain. The introduced Dual Phase Shift (DPS) proportional voltage conversion ratio control scheme is realized by manipulating the phase shifts of the gating signals in the DAB converter, to regulate the amount of DAB converter power flow in and out of the DC-link. Dynamic converter efficiency models are utilized to account for switching, conduction, copper and core losses. The control methodology is proposed on the basis of improving the individual efficiency of the DAB converter but with its parameters tuned to minimize the powertrain fuel consumption. Since DPS control has one additional degree of freedom as compared to Single Phase Shift (SPS) voltage control schemes, a Lagrange Multiplier optimization method is applied to minimize the leakage inductance peak current, the main cause for switching and conduction losses. The DPS control scheme is tested in simulations with a full HEV model and two associated conventional supervisory control algorithms, together with a tuned SPS proportional voltage conversion ratio control scheme, against a conventional PI control in which the DC-link voltage follows a constant reference. Nonlinear coupling difficulties associated with the integration of varying DC-link voltage in the powertrain are also exposed and addressed

School Violence Among a Nationally Representative Sample of Adolescents in Chile

Background: School violence is widely acknowledged as a public health problem with considerable consequences on student learning and social development. There are also a wide range of health consequences. A large share of previous research on school violence has focused on populations in the global north, with significant gaps in the state of knowledge in the world's emerging economies. To this end, the present study provides an examination of correlates for school-based violence in Chile using a nationally representative cohort.Methods: Six independent variables were considered (age, sex, physical activity, sedentary life style, bullying victimization, food insecurity) within a logistic regression model to ascertain the strength and direction of associations with physical fighting.Results: Among the surveyed students, ~13.08% reported being involved in two or more physical fights during the twelve month recall period. Males were significantly over represented among those reporting being involved in a fight OR 2.91 (CI = 1.98–4.27). Those who reported experiencing food insecurity were 5.29 (CI = 1.43–19.50) times more likely to have been involved in a physical fight. Students who reported being bullied were 2.41 (CI = 1.67–3.47) times more likely to have been involved in physical fights. While age provided protection from involvement in physical fights with an adjusted odds ratio of 0.91 (CI = 0.84–0.98).Conclusion: Consistent with previous research, our results suggest that the use of school-based interventions that target multiple risk behaviors may be helpful in reducing rates of physical fighting.</p

Investigation of Non-linear Chirp Coding for Improved Second Harmonic Pulse Compression

Non-linear frequency-modulated (NLFM) chirp coding was investigated to improve the pulse compression of the second harmonic chirp signal by reducing the range side lobe level. The problem of spectral overlap between the fundamental component and second harmonic component (SHC) was also investigated. Therefore, two methods were proposed: method I for the non-overlap condition and method II with the pulse inversion technique for the overlap harmonic condition. In both methods, the performance of the NLFM chirp was compared with that of the reference LFM chirp signals. Experiments were performed using a 2.25 MHz transducer mounted coaxially at a distance of 5 cm with a 1 mm hydrophone in a water tank, and the peak negative pressure of 300 kPa was set at the receiver. Both simulations and experimental results revealed that the peak side lobe level (PSL) of the compressed SHC of the NLFM chirp was improved by at least 13 dB in method I and 5 dB in method II when compared with the PSL of LFM chirps. Similarly, the integrated side lobe level (ISL) of the compressed SHC of the NLFM chirp was improved by at least 8 dB when compared with the ISL of LFM chirps. In both methods, the axial main lobe width of the compressed NLFM chirp was comparable to that of the LFM signals. The signal-to-noise ratio of the SHC of NLFM was improved by as much as 0.8 dB, when compared with the SHC of the LFM signal having the same energy level. The results also revealed the robustness of the NLFM chirp under a frequency-dependent attenuation of 0.5 dB/cm·MHz up to a penetration depth of 5 cm and a Doppler shift up to 12 kHz

Global School-based Student Health Survey reveals correlates of suicidal behaviors in Brunei Darussalam: a nationwide cross-sectional study

This study aimed to determine the prevalence of and correlates for suicidal behaviors among school attending adolescents in Brunei.Nationally representative cross-sectional data on (n=2599) adolescents derived from the Global School-based Health Survey in Brunei Darussalam were examined. Data on suicidal behaviors, psychosocial and demographic characteristics were analyzed using multiple logistic regression taking survey design into account.Twelve months prior to being surveyed, the prevalence of suicidal behaviors was 9.3%, 6.5% and 5.9% for suicidal ideation, suicidal plan and suicidal attempt, respectively. Females were overrepresented in attempts (61.2%). Several self-reported characteristics such as suicide ideation (69%), anxiety (28%), and loneliness (30%) were significantly different between the attempters of suicide and non-attempters (p less than 0.05). Also, some suicide-related behaviors such as having planned a suicide (52%), being bullied (21%), involved in a physical fight (29%), serious injury (29%), early sexual debut (8.5%), alcohol use at early age (21%), alcohol use in the past 30-days (12%), and being physically attacked (30%) differed by suicide category (p less than 0.05). Compared to those who did not report attempting suicide, attempters were more likely to have suicide ideation (OR=10.58; 95% CI 5.10, 21.97); have planned suicide (OR=9.82; 95% CI 4.60, 20.96); or sustained serious injury (OR=4.01; 95% CI 2.03, 7.93) within the recall period.This study provided evidence, which overall confirm that the psycho-social environment in school settings modify suicidal behavior. The results, taken together emphasize the importance of the school environment on the development of school attending adolescents. Where possible, the results may provide additional information on which self-reported behaviors represent avenues for potential preventive programming.</div

Physical Fighting among School-Attending Adolescents in El Salvador: An Examination of the 2013 Global School-Based Health Survey

Background: Violence among school-attending adolescents is an important public health problem worldwide. The present study examined demographic correlates for physical fighting behavior among a nationally representative sample of school-attending adolescents in El Salvador. Methods: Initial cross-tabulations to screen for correlations was then followed by logistic regression to understand the direction and the strength of selected demographic variables for physical fighting behavior, which occurred within a 12 month period of recall. Results: Out of a sample of 1910 school-attending adolescents in El Salvador, 11.5% reported having been involved in two or more physical fights during the recall period. Regression analyses indicated that being male (OR = 3.55; 95% CI = 2.11–6.00); having experienced bullying (OR = 2.16; 95% CI = 1.44–3.24); physical activity (OR 0.61; 95% CI 0.46–0.80); a sedentary lifestyle (OR 1.54; 95% CI 1.05–2.27), suicide planning (OR 2.28; 95% CI 1.46–3.56), and having non-understanding parents (OR = 1.45; 95% CI 1.06–1.98) were significantly associated with physical fighting among the sampled adolescents. Conclusion: Within the limitations of cross-sectional surveys conducted in school settings, the results of the present study suggest that giving attention to preventing bullying behavior among males and involving parents should be components of a multi-pronged strategy to preventing physical fighting in schools in El Salvador

Head and Neck Trauma in a Rapidly Growing African Metropolis: A Two-Year Audit of Hospital Admissions

Understanding injury-related burdens is an essential part of trauma quality improvement programs aimed at decreasing morbidity and mortality. This is especially the case in low and middle-income country settings where data on injuries remains limited. The aim of this study was to audit the types of head and neck injuries, which have been diagnosed among patients admitted to a major national hospital in the context of a rapidly growing sub Saharan city. Data were collected retrospectively for head and neck trauma from the Muhimbili National Hospital (MNH) in Dar es Salaam, Tanzania from the years 2016 and 2017. Distribution of ICD-10 codes by age and sex for the five most common diagnoses were determined using frequencies and percentages. The most common diagnosis was ICD-10-S02 (fracture of skull and facial bones) with 277 cases (44.1%), which was followed by S05 (injury of the eye and orbit), 114 cases (18.2%), and S09 (other and unspecified injuries of head) 77 cases (12.3%). The mean ages of admission for these three diagnoses were 28.1 (SD: 11.6), 23.8 (SD: 18.9), and 30.8 (SD: 18.0) years, respectively. This study provides information on the overall burden of head and neck trauma at a major regional tertiary care facility. It provides an initial understanding of the burden of head and neck trauma and suggests follow-up in the form of clarification of injury mechanisms and contextual factors for future work.</p

Magnetite (Fe 3

Accumulation of heavy metals in the ecosystem and their toxic effects through food chain can cause serious ecological and health problems. In the present study, experiments were performed to understand how the addition of magnetite (Fe3O4) nanoparticles reduces the toxicity caused by Cd, Pb, Cu, and Zn in cucumber plants. Plant growth parameters, lipid peroxidation, and antioxidant enzymes were measured in seedling samples treated with either metals or metals supplemented with Fe3O4 to demonstrate the reduction in metal-induced oxidative stress conferred by Fe3O4. Results showed that the toxic effect of metals on seedling growth parameters can be arranged in the rank order of inhibition as follows: Cu > Cd > Zn > Pb. Exposure to metals significantly decreased the seedlings growth, the activities of superoxide dismutase (SOD) and peroxidases (POD), while the malondialdehyde (MDA) content significantly increased in cucumber seedlings. The reducing activity of nano-Fe3O4 against heavy metals stresses was confirmed in this study by the decrease in MDA content. The correlation between the decrease of MDA concentration and the increase in SOD and POD activities in the presence of nano-Fe3O4 suggest that the MDA reduction in the tested seedlings can result from the increased enzyme activity

Concomitant primary breast carcinoma and primary choroidal melanoma: a case report

<p>Abstract</p> <p>Introduction</p> <p>Choroidal melanoma and choroidal metastasis are distinct pathological entities with very different treatments and prognoses. They may be difficult to distinguish to the untrained observer.</p> <p>Case presentation</p> <p>A case of concomitant choroidal melanoma in a woman with primary breast carcinoma is described. The choroidal lesion was thought initially to be a metastasis, and treated with external beam radiotherapy. The tumour did not regress but remained stable in size for a period of three years. Following referral to an ophthalmologist, the diagnosis was revised after re-evaluation of the clinical, ultrasonographic and angiographic findings.</p> <p>Conclusion</p> <p>Although metastases are the most common ocular tumour, a differential diagnosis of a concurrent primary ocular malignancy should always be considered, even in patients with known malignant disease. Thorough ophthalmic evaluation is important, as multiple primary malignancies may occur concomitantly. The prognostic and therapeutic implications of accurate diagnosis by an ophthalmologist are of profound significance to affected patients and their families.</p

Privacy-enhancing Aggregation of Internet of Things Data via Sensors Grouping

Big data collection practices using Internet of Things (IoT) pervasive technologies are often privacy-intrusive and result in surveillance, profiling, and discriminatory actions over citizens that in turn undermine the participation of citizens to the development of sustainable smart cities. Nevertheless, real-time data analytics and aggregate information from IoT devices open up tremendous opportunities for managing smart city infrastructures. The privacy-enhancing aggregation of distributed sensor data, such as residential energy consumption or traffic information, is the research focus of this paper. Citizens have the option to choose their privacy level by reducing the quality of the shared data at a cost of a lower accuracy in data analytics services. A baseline scenario is considered in which IoT sensor data are shared directly with an untrustworthy central aggregator. A grouping mechanism is introduced that improves privacy by sharing data aggregated first at a group level compared as opposed to sharing data directly to the central aggregator. Group-level aggregation obfuscates sensor data of individuals, in a similar fashion as differential privacy and homomorphic encryption schemes, thus inference of privacy-sensitive information from single sensors becomes computationally harder compared to the baseline scenario. The proposed system is evaluated using real-world data from two smart city pilot projects. Privacy under grouping increases, while preserving the accuracy of the baseline scenario. Intra-group influences of privacy by one group member on the other ones are measured and fairness on privacy is found to be maximized between group members with similar privacy choices. Several grouping strategies are compared. Grouping by proximity of privacy choices provides the highest privacy gains. The implications of the strategy on the design of incentives mechanisms are discussed

Synergistic Antibacterial Effects of Metallic Nanoparticle Combinations

© The Author(s) 2019.Metallic nanoparticles have unique antimicrobial properties that make them suitable for use within medical and pharmaceutical devices to prevent the spread of infection in healthcare. The use of nanoparticles in healthcare is on the increase with silver being used in many devices. However, not all metallic nanoparticles can target and kill all disease-causing bacteria. To overcome this, a combination of several different metallic nanoparticles were used in this study to compare effects of multiple metallic nanoparticles when in combination than when used singly, as single elemental nanoparticles (SENPs), against two common hospital acquired pathogens (Staphylococcus aureus and Pseudomonas. aeruginosa). Flow cytometry LIVE/DEAD assay was used to determine rates of cell death within a bacterial population when exposed to the nanoparticles. Results were analysed using linear models to compare effectiveness of three different metallic nanoparticles, tungsten carbide (WC), silver (Ag) and copper (Cu), in combination and separately. Results show that when the nanoparticles are placed in combination (NPCs), antimicrobial effects significantly increase than when compared with SENPs (P < 0.01). This study demonstrates that certain metallic nanoparticles can be used in combination to improve the antimicrobial efficiency in destroying morphologically distinct pathogens within the healthcare and pharmaceutical industry.Peer reviewe