3,688 research outputs found
Effect of connecting shunt capacitor on nonlinear load terminals
This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. Copyright @ 2003 IEEEThe use of terminal shunt capacitance has different effects on the displacement factor and distortion factor components of the power factor. These effects are considered for nonlinear loads with ideal supply, and also where the supply impedance exists but is small compared with the load impedance. Optimization of the displacement factor is found to result in reduction of the distortion factor to a minimum value
Biological pretreatment of lignocellulosic biomass for volatile fatty acid production
Volatile fatty acid (VFA) platform has been suggested as a potential alternative to sugar platform for the production of biofuels and fine chemicals. Biomass-derived VFA is one of the potential alternatives for VFA production that required only a mild pretreatment process to open up the lignocellulosic biomass structure for anaerobic digestion (AD), whereas some of the biomass like food waste, manure, sludge, or any biodegradable biomass do not require any pretreatments. Lignocellulosic biomass such as hardwood (forestry and agricultural biomass) does require pretreatments to remove lignin or to alter the lignocellulosic compositions. Besides, VFA also can be produced from all types of organic polymers (carbohydrates, protein, and lipid) that will increase the VFA yield as compared with sugar platform, which can be produced from carbohydrate polymers only. Biological pretreatment of lignocellulosic biomass offers an advantage for the production of VFA. This chapter will focus on suitable pretreatment strategies for VFA production especially on the biological pretreatments
Fluorescence spectroscopy for analysing deterioration of palm olein in batch deep-fat frying
Palm olein has been commercially used as frying medium in batch deep-fat frying. During frying, the oil usually deteriorates due to the exposure to high temperature. In this study, a fluorescence spectroscopy technique was applied to monitor the deterioration of refined, bleached, and deodorized palm olein (RBDPO) in batch deep-fat frying. 22.5 kg of French fries were used as the frying material. In 30 batches, the french fries were intermittently fried at 185 ± 5°C for eight hours a day over five consecutive days capturing 40 hours. The fluorescence intensity of the RBDPO was recorded with excitation at 390 nm and resulting emission of 465 nm. The fluorescence intensity of the RBDPO over five days of frying decreased considering the wavelength range of emission 430-640 nm and excitation 360-430 nm. The decreased in intensity of fluorescence emission and excitation spectra were inversely correlated with the FFA content of the oil samples. This study demonstrates the potential of fluorescence spectroscopy in monitoring the deterioration of RBDPO during batch deep-fat frying
Modified EDF Goodness of Fit Tests for Logistic Distribution under SRS and RSS
Modified forms of goodness of fit tests are presented for the logistic distribution using statistics based on the empirical distribution function (EDF). A method to improve the power of the modified EDF goodness of fit tests is introduced based on Ranked Set sampling (RSS). Data are collected via the Ranked Set Sampling (RSS) technique (McIntyre, 1952). Critical values for the logistic distribution with unknown parameters are provided and the powers of the tests are given for a number of alternative distributions. A simulation study is presented to illustrate the power of the new method
Ex-situ experimental set-up for pink guava juice fouling deposit study
A study has been conducted on pink guava juice (PGJ) fouling deposit. Several ex-situ experimental rigs were set-up to obtain PGJ fouling deposit, while the best ex-situ experimental rig was also selected. PGJ was heated at 93°C and its fouling deposit was obtained after 1 hour of heating. Then, it was used for the ex-situ cleaning study at 1 litre min-1, at several temperatures (70, 80 and 90°C), and in some chemical concentrations (1.6 v/v% of Maxiclean CP6 or 0.325 % OH–; 1.8 v/v% of Maxiclean CP6 or 0.369 % OH–; 2.0 v/v% of Maxiclean CP6 or 0.44 % OH–). The best cleaning combinations were investigated. Carbohydrate is the main content in the fouling deposit. The morphology of the deposit was studied using SEM and it showed an aggregated structure. The cleaning process improved as the temperature increased with the increasing of the chemical solution concentration. The shortest cleaning time was 40 minutes, for cleaning using 2.0 v/v % of Maxiclean CP6 (0.44 % OH–) at 90°C
Synthesis of Diarylpyrazoles Containing a Phenylsulphone or Carbonitrile Moiety and their Chalcones as Possible Anti-Inflammatory Agents
A series of chalcone-based diarylpyrazoles containing a phenylsulphone or carbonitrile moiety was synthesized. Thus, 3-acetylpyrazoles 6a–c and 10a–c were used as useful substrates in facile synthesis of functional pyrazoles 7a–f and 11a–f, respectively. The anti-inflammatory activity and ulcerogenic effect were evaluated and some of the obtained products possessed a significant anti-inflammatory activity. 1-[1-(3-Methylphenyl)-5-phenyl-4-(phenylsulfonyl)-1H-pyrazol-3-yl]ethanone (6b) showed a high activity when compared with indomethacin as reference drug with lower gastrointestinal (GI) profile. Furthermore, molecular docking studies were performed in order to rationalize the obtained biological results
Dexmedetomidine as an adjuvant to bupivacaine in ultrasound fascia iliaca compartment block in proximal end femur surgeries
Background: Fracture neck femur is a common cause of hospital admission among the elderly population. Many patients admitted with fracture femur have long-standing cardiac, hepatic or renal problems. This makes a challenge to balance adequate analgesia with side effects of opioids. Fascia iliaca compartment block (FICB) is one of the peripheral nerve block techniques. It became widely used in providing postoperative analgesia for patient with fracture neck femur either in emergency department or in the operating room.Objective: To evaluate the efficacy of addition of dexmedetomidine to bupivacaine on the duration and quality of postoperative analgesia in ultrasound guided fascia iliaca compartment block in proximal end femur surgeries.Patients and methods: Sixty patients with American Society of Anesthesiologists (ASA) physical status I - II of both sexes aged from 20-60 years scheduled for proximal end femur surgeries. They were randomly assigned to one of two equal groups (n=30 each), using closed envelope technique: Bupivacaine group (B group), and Bupivacaine + dexmedetomidine (BD group). Result: Our study demonstrated prolongation of postoperative analgesia in bupivacaine-dexmedetomidine group (BD) compared to bupivacaine group (B). It showed statistically significant reduction in cumulative pethidine doses and prolongation in the time till first rescue analgesic is required in the BD group in comparison with the B group in the first 24 hours. Hemodynamic changes and incidence of side effects, were statistically insignificant among the two groups. Conclusion: Addition of dexmedetomidine, as an adjuvant to the local anesthetic bupivacaine, in ultrasound fascia iliaca compartment block provides prolongation of the duration of postoperative analgesia with less opioid consumption without remarkable side effects
Brain-derived neurotrophic factor in asthmatic children
Background: Brain-derived neurotrophic factor (BDNF) regulates the cross-talk between the immune and nervous systems which may play an important role in asthma pathophysiology. Objective: This study was aimed to investigate the relation between BDNF and asthma exacerbation and severity, and to study its possible correlation to eosinophilic counts in blood and sputum. Methods: Twenty-seven asthmatic children were studied during both exacerbation and remission. According to acute exacerbation severity as assessed clinically and by peak expiratory flow rate (PEFR), they were equally subdivided into 3 groups (mild, moderate and severe). Serum and sputum BDNF levels as well as blood and sputum eosinophilic counts were estimated in all patients in comparison to 30 healthy children with no personal or family history of atopy. Results: BDNF levels (in serum and sputum) and eosinophilic counts (in blood and sputum) were significantly elevated in asthmatic patients, whether studied as one group or subgrouped into mild, moderate and severe as compared to controls. Patients with mild, moderate and severe acute asthma exacerbation had significantly higher values of BDNF (in serum and sputum) and eosinophilic count (in blood and sputum) than the corresponding values measured during remission. The latter values were still higher than those of the control group. BDNF in serum and sputum indirectly correlated with asthma severity as evidenced by their negative correlation with PEFR. However, sputum BDNF correlated better with the severity of asthma exacerbation as evidenced directly by its significant increase with clinical severity. Both serum and sputum BDNF levels revealed significant positive correlations with eosinophilic count in blood and sputum among all studied groups. Conclusion: BDNF probably plays a role in the evolution of asthma exacerbation and it reflects the degree of asthma severity during exacerbation. It might also represent an objective indicator of remission and treatment efficacy. Studies with specific BDNF receptor antagonists or synthesis inhibitors are required as BDNF may prove to be a reasonable target for a new therapy in future.Keywords: BDNF, neurotrophins, bronchial asthma, asthma severity, neurogenic inflammationEgypt J Pediatr Allergy Immunol 2003; 1(2): 102-
Effect of routine pre-operative urethral catheterization of women undergoing minor gynaecological surgeries on urinary symptoms and urinary infections: a randomized control study
Background: The prevalence of urinary tract infection increases in young sexually active women, and women with previous UTI. Routine urethral catheterization performed for bladder evacuation before minor gynecological procedures and it is not clear whether this routine urethral catheterization associated with increased incidence of bacteriuria or UTIs or not. This study designed to detect the effect of routine uretheral catheterization for women undergoing minor gynecological surgeries on urinary symptoms and urinary infections.Methods: Two hundred and forty women infertile women scheduled for uterine assessment by diagnostic hysteroscopy before in-vitro fertilization in assisted reproduction unit of Ahmadi Hospital, Kuwait Oil Company were included in this study. Participants were randomized into; group I (catheterized group) and group II (non-catheterized group). Participants’ urine samples compared pre-operatively and post-operatively and they asked to complete about their pre and post-operative urinary symptoms.Results: Post-operative dysuria, frequency and urgency were significantly higher in catheterized group (22 (18.33%), 26 (21.66%) and 18 (15%); respectively) compared to non- catheterized group [5 (4.16%), 7 (5.83%) and 4 (3.33%); respectively]. Relative risk of dysuria, frequency and urgency after catheterization were 4.4, 3.7 and 4.5; respectively (95% CI; 1.7-11.2, 1.67-8.22 and 1.56-12.9; respectively). Asymptomatic bacteriuria, UTIs and subsequent need for antimicrobial therapy were also significantly high in catheterized group [15 (12.5%), 18 (15%) and 18 (15%); respectively) compared to non-catheterized group (3 (2.5%), 2 (1.96%) and 2 (1.96%); respectively]. Relative risk of asymptomatic bacteriuria and UTIs after catheterization in women undergoing minor gynecological procedures were 5 and 9; respectively (95%CI; 1.48-16.8 and 2.1-37.9).Conclusions: Catheterization in women undergoing minor gynecological surgery was associated with increased risk of dysuria, frequency, urgency, ASB, UTIs and subsequent antimicrobial therapy. Surgeons should revise the practice of routine preoperative catheterization for women undergoing minor gynecological procedures
Impact Of Breast Feeding Versus Formula Feeding On Surgical Wound Healing In Infants During The First Three Months Of Age
Breast milk has antimicrobial and healing properties that actually can help the wound healing. Surgical infants are at a much higher risk for malnutrition as a result of increased metabolic demands from surgery, nutrient losses, and sepsis. Many methods of feeding are used postoperatively for infants; oral feeding (breast or formula milk), enteral, or parenteral feeding. Aim of this work was to assess the effect of breast-feeding versus formula feeding on surgical wound healing in infant during the first three months. Methods and materials: Comparative descriptive research design was used to carry out this study. It comprised 100 infants aged less than 3 months, they were divided into two equal groups as the following: Group 1: received breast milk feeding, Group 2: received formula milk feeding. Tools were developed by the researcher, after that the researcher fulfill assessment sheet and took anthropometric measurements for each infant then the photographs were taken by the researcher on the 7th postoperative day and reassessed for second time on the 14th day. Results: Out of the included breast-fed infants, 78 % were boys, while 22% were girls
- …