Materials Selection, Synthesis, and Dielectrical Properties of PVC Nanocomposites

Materials selection process for electrical insulation application was carried out using Cambridge Engineering Selector (CES) program. Melt mixing technique was applied to prepare polyvinyl-chloride- (PVC-) nanofumed silica and nanomontmorillonite clay composites. Surface analysis and particles dispersibility were examined using scanning electron microscope. Dielectrical properties were assessed using Hipot tester. An experimental work for dielectric loss of the nanocomposite materials has been investigated in a frequency range of 10 Hz–50 kHz. The initial results using CES program showed that microparticles of silica and clay can improve electrical insulation properties and modulus of elasticity of PVC. Nano-montmorillonite clay composites were synthesized and characterized. Experimental analyses displayed that trapping properties of matrix are highly modified by the presence of nanofillers. The nanofumed silica and nanoclay particles were dispersed homogenously in PVC up to 10% wt/wt. Dielectric loss tangent constant of PVC-nanoclay composites was decreased successfully from 0.57 to 0.5 at 100 Hz using fillers loading from 1% to 10% wt/wt, respectively. Nano-fumed silica showed a significant influence on the electrical resistivity of PVC by enhancing it up to 1 × 1011 Ohm·m

The impact of urban spatial structure on travel demand in the United States

The authors combine measures of urban form and public transit supply for 114 urbanized areas with the 1990 Nationwide Personal Transportation Survey to address two questions: (1) How do measures of urban form, including city shape, road density, the spatial distribution of population, and jobs-housing balance affect the annual miles driven and commute mode choices of U.S. households? (2) How does the supply of public transportation (annual route miles supplied and availability of transit stops) affect miles driven and commute mode choice? The authors find that jobs-housing balance, population centrality, and rail miles supplied significantly reduce the probability of driving to work in cities with some rail transit. Population centrality and jobs-housing balance have a significant impact on annual household vehicle miles traveled (VMT), as do city shape, road density, and (in rail cities) annual rail route miles supplied. The elasticity of VMT with respect to each variable is small, on the order of 0.10-0.20 in absolute value. However, changing several measures of form simultaneously can reduce annual VMT significantly. Moving the sample households from a city with the characteristics of Atlanta to a city with the characteristics of Boston reduces annual VMT by 25 percent.Housing&Human Habitats,Roads&Highways,Environmental Economics&Policies,Economic Theory&Research,Transport Economics Policy&Planning,Economic Theory&Research,Roads&Highways,Transport Economics Policy&Planning,Geographical Information Systems,Housing&Human Habitats

Numerical Analysis of Effect of Crack Location on the Crack Breathing Behavior

In this work, a three-dimensional finite element model was developed to investigate the crack breathing behavior at different crack locations considering the effect of unbalance force. A two-disk rotor with a crack is simulated using ABAQUS. The duration of each crack status (open, closed and partially open/closed) during a full shaft rotation was examined to analyse the crack breathing behavior. Unbalanced shaft crack breathing behavior was found to be different at different crack locations. The breathing behavior of crack along the shaft length is divided into different regions depending on the unbalance force and crack location. The simulated results in this work can be further utilised to obtain the time-varying stiffness matrix of the cracked shaft element under the influence of unbalance force

Performance comparison of selection nanoparticles for insulation of three core belted power cables

This paper presents an investigation on the enhancement of electrical insulations of power cables materials using a new multi-nanoparticles technique. It has been studied the effect of adding specified types and concentrations of nanoparticles to polymeric materials such as PVC for controlling on electric and dielectric performance. Prediction of effective dielectric constant has been done for the new nanocomposites based on Interphase Power Law (IPL) model. The multi-nanoparticles technique has been succeeded for enhancing electric and dielectric performance of power cables insulation compared with adding individual nanoparticles. Finally, it has been investigated on electric field distribution in the new proposed modern insulations for three-phase core belted power cables. This research has focused on studying development of PVC nanocomposite materials performance with electric field distribution superior to the unfilled matrix, and has stressed particularly the effect of filler volume fraction on the electric field distribution

Evaluating Delay Causes for Constructing Road Projects in Saudi Arabia

In this paper, we evaluate the causes of delays in road construction projects in Saudi Arabia. The research identifies four main groups of delay causes: external factors, contractor-related factors, project management factors, and environmental factors. External factors include changes in regulations and delays in obtaining permits and approvals. Contractor-related factors include inadequate resources and poor project planning. Project management factors encompass ineffective communication and poor coordination among stakeholders. Environmental factors include adverse weather conditions and unforeseen site conditions. The study recommends measures such as improved coordination, enhanced contract management, and advanced project management techniques to mitigate these delay causes. The findings provide valuable insights for stakeholders involved in road infrastructure development in Saudi Arabia, enabling them to implement strategies for timely project delivery and improved project performance

Social and Financial Incentives for Overcoming a Collective Action Problem

Addressing public health externalities often requires community-level collective action. Each person’s sanitation behavior can affect the health of neighbors. We report on a cluster randomized controlled trial conducted with 19,000 households in rural Bangladesh where we randomized (1) either group financial incentives or a non-financial “social recognition” reward, and (2) asking each household to make either a private pledge or a public pledge to maintain hygienic latrines. The group financial reward has the strongest impact in the short term (3 months), inducing a 7.5-12.5 percentage point increase in hygienic latrine ownership. Getting people to publicly commit to maintaining and using a hygienic latrine in front of their neighbors induced a 4.2-6.1 percentage point increase in hygienic latrine ownership in the short term. In the medium term (15 months), the effect of the financial reward dissipates while the effect of the public commitment persists. Neither social recognition nor private commitments produce effects statistically distinguishable from zero

Prevalence and resistant patterns of multidrug-resistant urinary tract infection caused by Escherichia coli among patients admitted to a teaching hospital

Background: Multi-drug resistant organisms, particularly in urinary tract infections, have become a significant concern in developing countries like Bangladesh. Physicians are facing challenges in treating hospitalized cases due to the ineffectiveness of conventional antibiotics and empirical treatment, as well as the emergence of multi-drug-resistant Escherichia coli. The main goal of the study was to observe the prevalence and resistant pattern of multidrug-resistant Escherichia coli urinary tract infections among patients admitted to a teaching hospital. Methods: The cross-sectional study was conducted between August 2011 to February 2012 at Uttara Adhunik Medical College Hospital (UAMCH), Dhaka, Bangladesh. It included 100 cases, and detailed information was obtained through a standardized protocol. Results: In a study of 100 UTI patients, 45 had MDR E. coli while 55 had non-MDR E. coli. Females accounted for 79% of the patients, with a mean age of 44.85±17.81 years. The majority of participants fell into the 31-40 years age group (28%) and 60 years age group (23%). Among the participants, 57% had a history of UTI while 43% had no previous UTI history. High resistance was observed against amoxicillin, amoxiclav, cephradine, cefuroxime, cefixime, ceftriaxone, ceftazidime, and nalidixic acid. However, ciprofloxacin (2.22%), levofloxacin (6.67%), and cotrimoxazole (31.11%) exhibited lower resistance rates among MDR samples. Imipenem and meropenem showed 100% effectiveness against all MDR samples. Conclusion: MDR E. coli rates were alarmingly high in a teaching hospital in Bangladesh. Excessive antimicrobial drug consumption globally has led to antibiotic-resistant E. coli isolates, posing challenges for effective UTI treatment worldwide. Antibiotic therapy remains crucial in controlling these invasive agents

Tackling Fluid Overload in a High-transporter Diabetic Patient on Continuous Ambulatory Peritoneal Dialysis

Introduction: Diabetic patients on continuous ambulatory peritoneal dialysis (CAPD) are more prone to fluid overload than non-diabetic patients, but the use of hypertonic glucose solutions to improve their ultrafiltration (UF) may hamper their glycemic control. Maintaining euvolemia in such patients may be tricky and needs special care. Case report: A 72 year old diabetic and hypertensive patient presented with severe fluid overload shortly after initiation of CAPD despite producing more than one liter of urine per day. He only achieved modest ultrafiltration (UF) during the day, and had a negative UF during the long hypertonic night dwell. Peritoneal equilibration tests (PET) confirmed that he was a high transporter, and his weekly Kt/V was found to be 1.36. Since automated peritoneal dialysis (APD) is not yet available in Sudan, the PD prescription was modified to comprise five short cycles during the day, including two short hypertonic daytime dwells, and a dry abdomen at night. This approach succeeded in improving his fluid status, but required the addition of intra-peritoneal soluble insulin to his regular subcutaneous insulin in order to achieve acceptable blood sugar control. After 8 months his residual renal function (RRF) had declined remarkably and he began to suffer from intermittent fluid overload of variable degrees. Nevertheless, we managed to maintain him satisfactorily on CAPD for 14 months. Conclusion: Simple measures such as omitting the night dwell and using five short cycles during the day, including two short hypertonic dwells, can be effective in controlling fluid overload in diabetic patients who have a high transporter status. Key words: CAPD, diabetes mellitus, fluid overload, residual renal Functio

Dietary intake and biomarkers of alpha linolenic acid and risk of all cause, cardiovascular, and cancer mortality: systematic review and dose-response meta-analysis of cohort studies

OBJECTIVE: To examine the associations between dietary intake and tissue biomarkers of alpha linolenic acid (ALA) and risk of mortality from all causes, cardiovascular disease (CVD), and cancer. DESIGN: Systematic review and meta-analysis of prospective cohort studies. DATA SOURCES: PubMed, Scopus, ISI Web of Science, and Google Scholar to 30 April 2021. STUDY SELECTION: Prospective cohort studies that reported the risk estimates for death from all causes, CVD, and cancer. DATA SYNTHESIS: Summary relative risks and 95% confidence intervals were calculated for the highest versus lowest categories of ALA intake using random effects and fixed effects models. Linear and non-linear dose-response analyses were conducted to assess the dose-response associations between ALA intake and mortality. RESULTS: 41 articles from prospective cohort studies were included in this systematic review and meta-analysis, totalling 1 197 564 participants. During follow-up ranging from two to 32 years, 198 113 deaths from all causes, 62 773 from CVD, and 65 954 from cancer were recorded. High intake of ALA compared with low intake was significantly associated with a lower risk of deaths from all causes (pooled relative risk 0.90, 95% confidence interval 0.83 to 0.97, I2=77.8%, 15 studies), CVD (0.92, 0.86 to 0.99, I2=48.2%, n=16), and coronary heart disease (CHD) (0.89, 0.81 to 0.97, I2=5.6%, n=9), and a slightly higher risk of cancer mortality (1.06, 1.02 to 1.11, I2=3.8%, n=10). In the dose-response analysis, a 1 g/day increase in ALA intake (equivalent to one tablespoon of canola oil or 0.5 ounces of walnut) was associated with a 5% lower risk of all cause (0.95, 0.91 to 0.99, I2=76.2%, n=12) and CVD mortality (0.95, 0.91 to 0.98, I2=30.7%, n=14). The pooled relative risks for the highest compared with lowest tissue levels of ALA indicated a significant inverse association with all cause mortality (0.95, 0.90 to 0.99, I2=8.2%, n=26). Also, based on the dose-response analysis, each 1 standard deviation increment in blood concentrations of ALA was associated with a lower risk of CHD mortality (0.92, 0.86 to 0.98, I2=37.1%, n=14). CONCLUSIONS: The findings show that dietary ALA intake is associated with a reduced risk of mortality from all causes, CVD, and CHD, and a slightly higher risk of cancer mortality, whereas higher blood levels of ALA are associated with a reduced risk of all cause and CHD mortality only. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021229487

The growth and characterization of GaInSe2 single Crystals

GalnSe(2) single crystals have been grown and characterized by experimental techniques such as high-resolution transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy and optical and electrical measurements. The samples were prepared in single-crystal form from a melt. The structural analysis indicates that GalnSe(2) has a hexagonal structure, and confirms the high quality of the produced single crystals. Quantitative information on electrical and optical properties of single-crystalline GalnSe(2) was obtained by investigating the resistivity and photoluminescence as a function of the temperature and excitation intensity