Significant Decrease In Power Research Articles

PID Evaluation of Transparent Backsheet Modules

This Work Deals with the Robustness of Transparent Backsheet Modules using Coating/PET/PVF (TPC) Polymer Layers when Exposed to an Extended Potential Induced Degradation (PID) Stress based on IEC 61215. Results show a Significant Power Decrease on the Front Side after 576h of Testing for Negative Voltage with Three Time more Impact at the Rear Side Despite the Absence of Glass. PID is Confirmed with Electroluminescence (EL) and Photoluminescence (PL). Measurements Showing the Appearance of Dark Areas on Several Cells and an Inhomogeneous Signal all Along the Module with “Light trails”. Moreover, Transmission Electron Microscopy Measurement Points out Sodium Presence at Both Cell Interface Despite POE Encapsulant and the Absence of Glass at the Rear Side. Two Types of PID Seem to be Present: Low Light Current-Voltage Measurements Suggest the Presence of PID-Potential at the Rear Side of the Cells And the Dark Area Could Be linked To PID-Corrosion Effect as Depassivation is observed with EL and PL.

Estimation of the power of a geothermal energy recovery system that uses a heat exchanger

Access to new sources of renewable energy free of CO2 emissions is one of the priority needs of the global economy. At great depths underground there are geothermal sources with temperatures of up to several hundred degrees. Recovery of energy from such sources may take place using a heat exchanger placed in rocks at great depths. Before starting the exploitation of such resources, it is necessary to estimate the performance and power of the source with the assumed system parameters. In the conducted research, simulations of the energy acquisition system in the Matlab-simulink environment were carried out. The model of heat flows with distributed variables was used for the simulation, describing changes in the temperature distribution in time and space. The steady-state power of the system, which is possible to download over a long period of time, was also estimated. The most important conclusion from the conducted is that after some time, depending on the power consumed, the system may experience a significant decrease in power. The decrease in power is caused by the cooling of the rocks around the heat exchanger and the thermal resistivity of the medium, which are the rocks.

Performance Analysis of Passive Retro-Reflector Based Tracking in Free-Space Optical Communications With Pointing Errors

In this correspondence, we propose a diversity-achieving retroreflector-based fine tracking system for free-space optical (FSO) communications. We show that multiple retroreflectors deployed around the communication telescope at the aerial vehicle save the payload capacity and enhance the outage performance of the fine tracking system. Through the analysis of the joint-pointing loss of the multiple retroreflectors, we derive the ordered moments of the received power. Our analysis can be further utilized for studies on multiple input multiple output (MIMO)-FSO. After the moment-based estimation of the received power distribution, we numerically analyze the outage performance. The greatest challenge of retroreflector-based FSO communication is a significant decrease in power. Still, our selected numerical results show that, from an outage perspective, the proposed method can surpass conventional methods.

UV‐induced degradation of high‐efficiency silicon PV modules with different cell architectures

AbstractDegradation from ultraviolet (UV) radiation has become prevalent in the front of solar cells due to the introduction of UV‐transmitting encapsulants in photovoltaic (PV) module construction. Here, we examine UV‐induced degradation (UVID) in various commercial, unencapsulated crystalline silicon cell technologies, including bifacial silicon heterojunction (HJ), interdigitated back contact (IBC), passivated emitter and rear contact (PERC), and passivated emitter rear totally diffused (PERT) solar cells. We performed UV exposure tests using UVA‐340 fluorescent lamps at 1.24 W·m−2 (at 340 nm) and 45°C through 4.02 MJ·m−2 (2000 h). Our results showed that modern cell architectures are more vulnerable to UVID, leading to a significant power decrease (−3.6% on average; −11.8% maximum) compared with the conventional aluminum back surface field (Al‐BSF) cells (<−1% on average). The power degradation is largely caused by the decrease in short‐circuit current and open‐circuit voltage. A greater power decrease is observed in bifacial cells with rear‐side exposure compared with those with front‐side exposure, indicating that the rear side is more susceptible to UV damage. Secondary ion mass spectroscopy (SIMS) confirmed an increase in hydrogen concentration near the Si/passivation interface in HJ and IBC cells after UV exposure; the excess of hydrogen could result in hydrogen‐induced degradation and subsequently cause higher recombination losses. Additionally, surface oxidation and hot‐carrier damage were identified in PERT cells. Using a spectral‐based analysis, we obtained an acceleration factor of 5× between unpackaged cells (containing a silicon nitride antireflective coating on the front) in the UV test and an encapsulated module (with the front glass and encapsulant blocking 90% of the UV at 294 nm and 353 nm, respectively) in outdoor conditions. From the analytical calculations, we show that a UV‐blocking encapsulant can reduce UV transmission in the module by an additional factor of ~50.

Effects of VNS stimulation on electrocorticography in patients with dual neuro- stimulation devices

BackgroundOne-third of epilepsy patients become refractory to anti-epileptic medications. In these patients neurostimulation devices are considered as potential treatment options. The FDA has approved vagal nerve stimulation (VNS) and responsive neurostimulation (RNS system) for the treatment of focal epilepsy. There is limited data on interaction between the two devices and their mechanism of action is actively being researched. Limited prior evidence suggests that acute VNS stimulation may reduce epileptiform activity and cause EEG desynchronization. Our study aims to isolate the effects of VNS on electrocorticography (ECoG) as recorded by the RNS system.MethodsECoG from 20 patients were obtained. For each patient, five pairs of ‘on’ recordings of 60-second VNS stimulation on ECoGs were compared to ‘off’ baseline 60s recordings. ECoGs were analyzed for differences in spectral content.ResultsPreliminary results show that acute VNS stimulation is associated with significant decrease in power (i.e. desynchronization) in the theta, beta, and (50–70 Hz) gamma bands.ConclusionThis study demonstrates desynchronization as a mechanism of action of VNS, as recorded by the RNS system. As more patients receive dual neurostimulators, it will be crucial to understand isolated effects of each device to optimize programming and improve therapeutic efficacy.navya.joseph@unmc.edu

Increasing power of generator on nonlinear magnetic nanostructure

Background: One of the most promising areas of development of modern electronics is the creation of spintronic devices, which should replace the traditional semiconductor elements. The use of electron spin as a carrier of information in magnetic nanostructures can radically change modern life. Objectives: The aim of this work is to find ways to increase the power of the generator on the magnetic nanostructure by changing its electrical circuit and more optimal external electromagnetic parameters that affect the state of electrons in the studied layered structure. Materials and methods: The solution of this problem is carried out by numerical simulation of the magnetic nanostructure using a specially created micromagnetic simulator, which implements an algorithm for the simultaneous solution of the system of Maxwell and Landau-Lifshitz-Hilbert equations. The solution of such a complex problem is accelerated by the use of a quasi-static approximation in solving the system of Maxwell's equations, which is justified by the small size of the calculation area compared to the depth of the skin layer. Further calculations of the electrodynamic system are performed using the finite element method. To obtain the best frequency and energy parameters of the generator, it is proposed to introduce a resonant circuit to the schematic diagram of the studied generator, which is excited by short nanosecond pulses. Results: A scheme of a generator on a magnetic nanostructure containing a resonator with concentrated parameters is proposed, and a system of nonlinear integro-differential equations with respect to electric currents is obtained in general. Numerical calculation of this system includes, in addition to the calculation of the scheme, also the modeling of a nonlinear electrodynamic structure by the finite element method. The energy and spectral characteristics of the studied generator are obtained. The search for the optimal values of the geometric parameters of the nanostructure and the magnitude of the external longitudinal magnetization is carried out. Conclusions: Due to the complex nature of nonlinear processes in the magnetic nanostructure, the use of an external resonator, which could improve the spectral parameters of the generated current, did not give a noticeable improvement. The influence of the value of the external magnetization on the output power of the generator is complex and nonlinear, but, in general, a decrease in the level of magnetization leads to a significant decrease in power. It is established that the thickness of the magnetic layer of 6 nm is optimal for improving the energy characteristics of the generator.

Direct brain recordings identify hippocampal and cortical networks that distinguish successful versus failed episodic memory retrieval

Human data collected using noninvasive imaging techniques have established the importance of parietal regions towards episodic memory retrieval, including the angular gyrus and posterior cingulate cortex. Such regions comprise part of a putative core episodic retrieval network. In free recall, comparisons between contextually appropriate and inappropriate recall events (i.e. prior list intrusions) provide the opportunity to study memory retrieval networks supporting veridical recall, and existing findings predict that differences in electrical activity in these brain regions should be identified according to the accuracy of recall. However, prior iEEG studies, utilizing principally subdural grid electrodes, have not fully characterized brain activity in parietal regions during memory retrieval and have not examined connectivity between core recollection areas and the hippocampus or prefrontal cortex. Here, we employed a data set obtained from 100 human patients implanted with stereo EEG electrodes for seizure mapping purposes as they performed a free recall task. This data set allowed us to separately analyze activity in midline versus lateral parietal brain regions, and in anterior versus posterior hippocampus, to identify areas in which retrieval-related activity predicted the recollection of a correct versus an incorrect memory. With the wide coverage afforded by the stereo EEG approach, we were also able to examine interregional connectivity. Our key findings were that differences in gamma band activity in the angular gyrus, precuneus, posterior temporal cortex, and posterior (more than anterior) hippocampus discriminated accurate versus inaccurate recall as well as active retrieval versus memory search. The left angular gyrus exhibited a significant power decrease preceding list intrusions as well as unique phase–amplitude coupling properties, whereas the prefrontal cortex was unique in exhibiting a power increase during list intrusions. Analysis of connectivity revealed significant hemispheric asymmetry, with relatively sparse left-sided functional connections compared to the right hemisphere. One exception to this finding was elevated connectivity between the prefrontal cortex and left angular gyrus. This finding is interpreted as evidence for the engagement of prefrontal cortex in memory monitoring and mnemonic decision-making.

Examination of engine cylinder-piston group damages

Results of investigations of engine cylinder-piston group (CPG) damages and causes of their occurrence are given. The object of the study is the KIA Ceed engine, which came for examination due to a significant decrease in power, increased consumption of motor oil, violation of the dynamics of the car. The analysis of the technical condition of the disassembled engine showed that the parts of the crank mechanism and the cylinder head have no operational damages. Serious damages were detected only in the cylinder-piston group of the engine: abrasive wear of the working surfaces of cylinders, pistons and compression rings, coking of oil removal rings, deposits on the surfaces of all pistons of the engine. According to the results of the studies, the cause of loss of efficiency by the engine is the destruction of the ceramic catalyst, the products of which in the form of ground powdered substance enter the cylinders together with the exhaust gases. This occurs at the moment of simultaneous opening of exhaust valves of two cylinders having different exhaust gas pressure. A small amount thereof, together with the catalyst breakage products, penetrates the lower pressure cylinder through the manifold. A study of the substance of deposits on the pistons of the engine and the destruction products of the elements of the ceramic catalyst (cordierite Al4Mg2O16Si5), carried out on the powder diffractometer BRUKER AXS, showed the identity of their diffraction composition. This indicates that damage to the parts of the CPG and loss of performance by the engine is caused by destruction of the ceramic catalyst.

Beta-band power modulation in the human hippocampus during a reaching task

Objective. Characterize the role of the beta-band (13–30 Hz) in the human hippocampus during the execution of voluntary movement. Approach. We recorded electrophysiological activity in human hippocampus during a reach task using stereotactic electroencephalography (SEEG). SEEG has previously been utilized to study the theta band (3–8 Hz) in conflict processing and spatial navigation, but most studies of hippocampal activity during movement have used noninvasive measures such as fMRI. We analyzed modulation in the beta band (13–30 Hz), which is known to play a prominent role throughout the motor system including the cerebral cortex and basal ganglia. We conducted the classic ‘center-out’ direct-reach experiment with nine patients undergoing surgical treatment for medically refractory epilepsy. Main results. In seven of the nine patients, power spectral analysis showed a statistically significant decrease in power within the beta band (13–30 Hz) during the response phase, compared to the fixation phase, of the center-out direct-reach task using the Wilcoxon signed-rank hypothesis test (p < 0.05). Significance. This finding is consistent with previous literature suggesting that the hippocampus may be involved in the execution of movement, and it is the first time that changes in beta-band power have been demonstrated in the hippocampus using human electrophysiology. Our findings suggest that beta-band modulation in the human hippocampus may play a role in the execution of voluntary movement.

THE NEUROPHENOMENOLOGY OF OUT-OF-BODY EXPERIENCES INDUCED BY HYPNOTIC SUGGESTIONS

Inducing out-of-body experiences in hypnosis (H-OBEs) offers an almost unique opportunity to investigate them under controlled conditions. OBEs were induced as an imaginative task in a resting condition (I-OBE) or in hypnosis (H-OBE) in a group of 15 high hypnotizable subjects. A 32-channel EEG was recorded, and the spectral power and imaginary coherence of each frequency band and each couple of electrodes were calculated. At the end of each session, the Phenomenology of Consciousness Inventory (PCI) was administered to assess the phenomenological aspects of the subjects’ experience. Significantly higher scores in the altered state, positive affect altered experience, and attention subdimensions of the PCI were reported in H-OBE than in I-OBE, which were associated with a significant decrease of power in beta and gamma band activity in right parieto-temporal derivations. These results suggest that the H-OBE may offer a useful experimental model of spontaneous OBEs.

Instantaneous Responses of on-grid PV Plants to Changes in Environmental and Weather Conditions

The operation of an on-grid, 20 KW, PV, pilot plant is analyzed. The instantaneous environmental and weather conditions including solar irradiance, temperature, and wind speed are recorded and analyzed, simultaneously along with, the instantaneous data from the plant including PV module temperature, generated power, current, and voltage. The power decreases with increasing ambient temperature. Increasing solar irradiance increases the temperature difference between modules and ambient. Instantaneous energy and exergy efficiencies during three different days, representing sunny, partly cloudy, and cloudy days, are further calculated. The energy efficiency varies between 5.76% and 15.53%, while that of exergy varies between 4.84% and 15.73%. For cloudy days, the exergy efficiency is higher than that of energy efficiency, while for a sunny day it is in reverse. Another important parameter affecting the generated power is partial shading on PV modules, particularly during early mornings and late afternoons. The instantaneous shading varies between 3% and 9%, because of small azimuth and elevation angles. It was found that partial shading of only 4.73% on PV modules may result significant power decrease of more than 52.3%. A new algorithm based on Fuzzy Logic is proposed to overcome the power decrease even under partial shading conditions.

Respuesta del balance simpático-parasimpático de la variabilidad de la frecuencia cardíaca durante una semana de entrenamiento aeróbico en ciclistas de ruta

ObjectiveTo describe the response of the sympathetic-parasympathetic balance after a week of aerobic training volume in road cyclists. MethodsThe study was based on a non experimental transectional design. A non-random sample of five cyclists men. All participates in category “All competitors” of the national circuit (27.0±1.9 years, 170.0±6.6cm, 66.0±4.3kg). Subjects were evaluated for six days with aerobic training (108.4±49.5km per day). Each day the autonomic balance through the ratio LF/HF was measured, at rest and immediately after training. ResultsMean values of RR (1205.9±35.2 to 993.7±61.2 at baseline and post-training respectively) interval show significant difference (p<0.05). The values of the ratio Low Frequency/High Frequency (0.861±0.090 to 3.067±0.59 at baseline and post-training respectively) show that there is an activation of the autonomic balance immediately completed the training (p<0.05). The High Frequency power of autonomic balance (2567±697 to 926±367 at baseline and post-training respectively), shows a significant decline straight after training and start recovery (p<0.05). ConclusionsThe results of this study show a significant increase in the response of the autonomic balance of the ratio Low Frequency/High Frequency after training. Furthermore, a significant decrease in power of the High Frequency band during recovery may involve and increased activity of the parasympathetic response. These changes can help to the control and design of individual training programs for road cycling as well as being an inexpensive and non-invasive tool.

Long-Lasting Cortical Reorganization as the Result of Motor Imagery of Throwing a Ball in a Virtual Tennis Court.

In order to characterize the neural signature of a motor imagery (MI) task, the present study investigates for the first time the oscillation characteristics including both of the time-frequency measurements, event related spectral perturbation and intertrial coherence (ITC) underlying the variations in the temporal measurements (event related potentials, ERP) directly related to a MI task. We hypothesize that significant variations in both of the time-frequency measurements underlie the specific changes in the ERP directly related to MI. For the MI task, we chose a simple everyday task (throwing a tennis ball), that does not require any particular motor expertise, set within the controlled virtual reality scenario of a tennis court. When compared to the rest condition a consistent, long-lasting negative fronto-central ERP wave was accompanied by significant changes in both time frequency measurements suggesting long-lasting cortical activity reorganization. The ERP wave was characterized by two peaks at about 300 ms (N300) and 1000 ms (N1000). The N300 component was centrally localized on the scalp and was accompanied by significant phase consistency in the delta brain rhythms in the contralateral central scalp areas. The N1000 component spread wider centrally and was accompanied by a significant power decrease (or event related desynchronization) in low beta brain rhythms localized in fronto-precentral and parieto-occipital scalp areas and also by a significant power increase (or event related synchronization) in theta brain rhythms spreading fronto-centrally. During the transition from N300 to N1000, a contralateral alpha (mu) as well as post-central and parieto-theta rhythms occurred. The visual representation of movement formed in the minds of participants might underlie a top-down process from the fronto-central areas which is reflected by the amplitude changes observed in the fronto-central ERPs and by the significant phase synchrony in contralateral fronto-central delta and contralateral central mu to parietal theta presented here.

Encoding of point of view during action observation in the local field potentials of macaque area F5.

The discovery of mirror neurons compellingly shows that the monkey premotor area F5 is active not only during the execution but also during the observation of goal-directed motor acts. Previous studies have addressed the functioning of the mirror-neuron system at the single-unit level. Here, we tackled this research question at the network level by analysing local field potentials in area F5 while the monkey was presented with goal-directed actions executed by a human or monkey actor and observed either from a first-person or third-person perspective. Our analysis showed that rhythmic responses are not only present in area F5 during action observation, but are also modulated by the point of view. Observing an action from a subjective point of view produced significantly higher power in the low-frequency band (2-10 Hz) than observing the same action from a frontal view. Interestingly, an increase in power in the 2-10 Hz band was also produced by the execution of goal-directed motor acts. Independently of the point of view, action observation also produced a significant decrease in power in the 15-40 Hz band and an increase in the 60-100 Hz band. These results suggest that, depending on the point of view, action observation might activate different processes in area F5. Furthermore, they may provide information about the functional architecture of action perception in primates.

Acute Effects of Dynamic versus Static Stretching on Aneorobic Power and Muscle Damage of Wrestlers

The purpose of the presentstudy isto investigate the acute effects of static and dynamic stretching protocols (3 minutes stretching) on a maximal anaerobic Wingate Test (WT) of wrestlers. Fifteen male wrestlers (age, 23.2± 2.6years; body mass, 79.2± 10.7 kg) volunteered to participate in the study. Peak power, mean power, and average powers of the subjects were assessed during the Wingate test (WT) after static stretching and dynamic stretching. CK (creatine kinase) values were obtained before and after ach stretching protocols. Two WT were performed after stretching. Data analysis included paired t-tests. It was found that dynamic stretching caused more power deficits than static stretching and CK (creatine kinase) values of wrestlers increased more with dynamic stretching. Dynamic stretching caused significant decrease in power ascompared to static stretching, considered to be because of different duration of stretchingand continuous dynamic activity may have caused exercise induced muscle damage.

Enregistrement magnéto-encéphalographique (MEG) de réminiscences du trauma chez des femmes souffrant de stress post-traumatique : une étude pilote

The experiment studied the effects of a short duration exposure to traumatic memories using magneto-encephalography (MEG). Nine right-handed DSM-4 PTSD patients were recruited from a unit for anxiety disorders and an organisation supporting victims of violence. In order to have a homogeneous sample, we included only women who suffered from civilian PTSD. Exclusion criteria were co-morbid major medical illness, metallic dental prostheses that would interfere in the magnetic measurement, and current drug treatment. All participants were free from neurological disease and had normal hearing. They signed a written informed consent form. An ethics committee accepted the study. A tape-recorded voice administered a script-driven imagery. The patients had to imagine, successively, a neutral image, a traumatic memory and rest, while MEG measured brain activities across delta, theta, alpha and beta bands. Each condition lasted three minutes. Heart rate (HR), anxiety and the vividness of mental images were recorded at the end of each phase. MEG power analysis was carried out with Statistical Parametric Mapping (SPM) 8. The signals were averaged for each of the three conditions of threeminutes duration. The dependent variable was a subtracted value: (trauma - rest) - (neutral - rest). The significance threshold was set at P<0.01. Anxiety and HR significantly increased during the trauma condition and returned to the neutral level during rest. The vividness of the mental imagery remained stable across the three conditions. The left-brain demonstrated a statistically significant power decrease in the secondary visual cortex (BA 18-19) in the delta band, the insula (BA13) in the beta band, the insula (BA13), premotor cortex (BA 6), Broca area (BA 44), and BA 43, in the alpha band. The symptom provocation protocol was successful in eliciting subjective anxiety and HR response in relation to traumatic memories. Our MEG results are in keeping with previous neuro-imagery studies showing decreased activities in the insula and Broca area during PTSD symptom provocation. However, we did not replicate the activation in the amygdala and the cingulate and prefrontal cortex found in some studies. Moreover, the within-group design, the small sample, and the inclusion of only female patients with milder dissociative symptoms limit our conclusions. The MEG protocol we used may also explain some partial discrepancies with previous MEG studies. However, our aim was to provoke a specific autobiographic recall of a traumatic event unfolding several sequential mental images along three minutes as in exposure therapy for PTSD. Despite its limitations, this pilot study is the first to provide MEG data during trauma recall. It suggests that recalling a specific traumatic event along three minutes results in hypo-activations of the brain regions regulating language and emotions. This paves the way to recording whole sessions of specific therapies for PTSD, with MEG using the millisecond resolution. MEG might be of interest to study the suppression of traumatic memories and their activation and habituation through prolonged graduated exposure in imagination across several sessions. MEG could also be used to study the effects of medication on PTSD symptoms. A controlled replication in a larger sample including male and female patients with various traumatic experiences is needed.

Globus pallidus internus oscillatory activity is related to movement speed

Local field potentials (LFPs) recorded from deep brain stimulation electrodes implanted in the globus pallidus internus (GPi) of patients with hyperkinetic movement disorders (dystonia and Tourette's syndrome) have shown desynchronized activity at 8-20Hz and synchronized activity at 30-90Hz during voluntary movements. However, the impact of the speed of the motor task on these frequency shifts is still unclear. In the current study, we recorded LFPs bilaterally from the GPi in seven patients with hyperkinetic movement disorders during normal/slow and fast horizontal line drawing movements as well as during rest. In comparison with rest, the low beta band showed a significant decrease in power during the motor tasks. Low beta power was more suppressed with increasing speed of the movement on the contralateral side. In contrast, a significant increase in power was induced by movements in the high beta and gamma bands on the contralateral side. When comparing slow and fast movements, the power of the low gamma frequency band was significantly elevated on the contralateral side with fast movements. In conclusion, an increase in movement speed changes the power of GPi oscillations by means of a reduction of the activity in the low beta band and an elevation of activity in the gamma band. The current study yields new insights into the physiological mechanism of GPi during the execution of the motor task at low and high speed.

Resting-State Neuronal Oscillatory Correlates of Working Memory Performance

PurposeWorking memory (WM) represents the brain’s ability to maintain information in a readily available state for short periods of time. This study examines the resting-state cortical activity patterns that are most associated with performance on a difficult working-memory task.MethodsMagnetoencephalographic (MEG) band-passed (delta/theta (1–7 Hz), alpha (8–13 Hz), beta (14–30 Hz)) and sensor based regional power was collected in a population of adult men (18–28 yrs, n = 24) in both an eyes-closed and eyes-open resting state. The normalized power within each resting state condition as well as the normalized change in power between eyes closed and open (zECO) were correlated with performance on a WM task. The regional and band-limited measures that were most associated with performance were then combined using singular value decomposition (SVD) to determine the degree to which zECO power was associated with performance on the three-back verbal WM task.ResultsChanges in power from eyes closed to open revealed a significant decrease in power in all band-widths that was most pronounced in the posterior brain regions (delta/theta band). zECO right posterior frontal and parietal cortex delta/theta power were found to be inversely correlated with three-back working memory performance. The SVD evaluation of the most correlated zECO metrics then provided a singular measure that was highly correlated with three-back performance (r = −0.73, p<0.0001).ConclusionOur results indicate that there is an association between WM performance and changes in resting-state power (right posterior frontal and parietal delta/theta power). Moreover, an SVD of the most associated zECO measures produces a composite resting-state metric of regional neural oscillatory power that has an improved association with WM performance. To our knowledge, this is the first investigation that has found that changes in resting state electromagnetic neural patterns are highly associated with verbal working memory performance.

Diesel vehicle performance on unaltered waste soybean oil blended with petroleum fuels

Interest in using unaltered vegetable oil as a fuel in diesel engines has experienced an increase due to uncertainty in the crude oil market supply and the detrimental effects petroleum fuels have on the environment. Unaltered vegetable oil blended with petroleum fuels is less expensive, uses less energy to produce and is more environmentally friendly compared to petroleum diesel or biodiesel. Here we investigate the engine performance of unaltered waste soybean oil blended with petroleum diesel and kerosene for three vehicles. Five biofuel blends ranging from 15% to 50% oil by volume were tested on a 2006 Jeep Liberty CRD, a 1999 Mercedes E300 and a 1984 Mercedes 300TD. A DynoJet 224x chassis dynamometer was used to test vehicle engine performance for horsepower and torque through a range of RPMs. Results for the Jeep showed a modest decrease in horsepower and torque compared to petroleum diesel ranging from 0.9% for the 15% oil blend to 5.0% lower for the 50% oil blend. However, a 30% oil blend showed statistically better performance (P<0.05) compared to petroleum diesel. For the 1999 Mercedes, horsepower performance was 1.1% lower for the 15% oil blend to 6.4% lower for the 50% oil blend. Engine performance for a 30% blend was statistically the same (P<0.05) compare to diesel. Finally, horsepower performance was 1.1% lower for the 15% oil blend to 4.7% lower for the 50% oil blend for the 1984 Mercedes. Overall, the performance on these oil blended fuels was excellent and, on average 1.1% lower than petroleum diesel for blends containing 40% or lower waste soybean oil content. The more significant decrease in power between the 40% and 50% oil blends indicates that oil content in these blended fuels should be no more than 40%.

Randomised, Multicentre, Placebo-controlled, Double-blind Crossover Study Investigating the Effect of Solifenacin and Oxybutynin in Elderly People with Mild Cognitive Impairment: The SENIOR Study

BackgroundCompared with younger people, the elderly are more likely to suffer from overactive bladder (OAB) and to have other chronic conditions that affect physical or cognitive function. Despite this, there are few data on the cognitive safety of antimuscarinic agents in older patients and none that examine the effect of these agents on those with mild cognitive impairment (MCI). ObjectiveTo evaluate cognitive effects during chronic stable dosing with solifenacin and oxybutynin versus placebo in older (≥75 yr) subjects with MCI. Design, setting, and participantsA randomised, double-blind, triple-crossover trial in 26 elderly volunteers with MCI. Cognitive function was assessed using Cognitive Drug Research (CDR) computerised testing. InterventionThree treatment periods of 21 d each with solifenacin 5mg once daily, oxybutynin 5mg twice daily, or placebo, separated by 21-d washout periods. Outcome measurements and statistical analysisThe primary end point was change from baseline in cognitive function with solifenacin at 6h postdose and oxybutynin at 2h postdose (time points close to their predicted time to peak concentration). Secondary end points included change in cognitive function at additional time points, and safety and tolerability assessments. Results and limitationsNeither agent was associated with significant changes from baseline in any of the five standard, composite outcomes of cognitive function (power of attention, continuity of attention, quality of working memory, quality of episodic memory, and speed of memory). In a secondary analysis, oxybutynin was associated with significant decreases in power and continuity of attention versus placebo at 1–2h postdose. Both agents were well tolerated, with the most frequently reported adverse event being mild or moderate dry mouth. ConclusionsSolifenacin had no detectable effect on cognition in this group of elderly people with MCI.