TESTING THE EFFICIENCY OF A SERIES HYBRID DRIVETRAIN FOR AGRICULTURAL APPLICATIONS

Because of high fuel costs and rising concern over controlling motor vehicle emissions, there has been a surge in the number of hybrid passenger vehicles on roads in recent years. This transition has not yet been seen with agricultural vehicles. With this in mind, this study created a test scheme to characterize and replicate agricultural loads, and design of a hybrid drivetrain that is suitable for agricultural purposes. Torque and power data were recorded from the controller area network of a tractor performing a baling operation. The recorded data was characterized using statistical and time series analyses, and converted into a simplified torque profile that could be run on a common type of dynamometer. The prototype series hybrid drivetrain was subjected to the simplified profile developed, and drivetrain efficiency was compared to the efficiency under constant load. The effect of battery pack, and engine size was also tested. On average, the prototype developed was not more efficient than a similarly sized standard geared vehicle, but there is significant room for further optimization

EFFECT OF COLLABORATIVE CONCEPT MAPPING TEACHING STRATEGY ON STUDENTS’ ACHIEVEMENT AND ATTITUDES TOWARDS MATHEMATICS IN SELECTED SECONDARY SCHOOLS IN KENYA

Achievement level in Mathematics in Secondary Schools in Kenya is still low despite numerous interventions. Conceptual understanding and attitudes have emerged in recent discoveries as the critical factors contributing to the continued inertia in performance in the subject. This study sought to establish the effect of Collaborative Concept Mapping (CCM) teaching strategy on secondary school students’ development of cognitive and affective domain. Specifically, the study sought to find out if there was any difference in Students’ achievement in mathematics, as a group and gender wise, and students’ attitude toward Mathematics subject when taught using the Collaborative Concept Mapping Teaching Strategy and the Conventional Methods of Instruction. The theoretical framework is based on constructivist theory which views learners as active constructors of meaning from input by processing it through existing cognitive structures and retaining it in the long-term memory. This study used a Quasi-experimental Solomon Four-Fold research design. The sample for the study comprised 161 form three students and 4 teachers of mathematics from 4 randomly selected sub-county co-educational secondary schools in the 4 sub-counties of Bomet County. The four co-educational schools were randomly assigned into two experimental (E1 & E2) and two control (C1 & C2) groups. Students in the experimental group were taught using Collaborative Concept Mapping (CCM) Teaching Strategy for three weeks while the control group was taught using Conventional Methods of Instruction. Students’ Attitude Towards Mathematics Questionnaire (SATMQ) was used to collect data. Circles Concept Achievement Test (CCAT) was administered to determine students’ conceptual understanding and achievement on the topic of ‘circles concept’ in Mathematics. Descriptive and inferential statistics were used in data analysis which included frequencies, mean, t-test and ANOVA. All the statistical tests were subjected to a test of significance at alpha (α) level of 0.05. The results revealed that there was statistically significant difference in mathematics achievement and attitudes towards mathematics in favour of CCM between students exposed to Collaborative Concept Mapping teaching strategy (CCM) and those taught using Conventional Method of Instruction. The findings further revealed that there was no statistically significant gender difference among students exposed to CCM teaching strategy. From the findings it can be concluded that the level of achievement in the learning of mathematical concepts and the attitude towards mathematics is marked higher when the students are taught using the Collaborative Concept Mapping Teaching Strategy (CCM) than when the conventional method is employed. Based on the findings, recommendations were made on the need for teachers to integrate Collaborative Concept Mapping Teaching Strategy (CCM) teaching strategy in the mathematics instruction to enhance conceptual understanding, improve achievement and foster positive attitude in the subject. There is also need for teacher training institutions to incorporate CCM as one of the strategies in mathematics instruction and that the serving teachers can be retooled to enable them to integrate CCM teaching strategy effectively in Mathematics learning. Mathematics curriculum developers need to restructure and integrate CCM among learner-centred strategies in Mathematics education.  Article visualizations

Influence of microphone housing on the directional response of piezoelectric mems microphones inspired by Ormia ochracea

The influence of custom microphone housings on the acoustic directionality and frequency response of a multiband bio-inspired MEMS microphone is presented. The 3.2 mm by 1.7 mm piezoelectric MEMS microphone, fabricated by a cost-effective multi-user process, has four frequency bands of operation below 10 kHz, with a desired first-order directionality for all four bands. 7×7×2.5 mm3 3-D-printed bespoke housings with varying acoustic access to the backside of the microphone membrane are investigated through simulation and experiment with respect to their influence on the directionality and frequency response to sound stimulus. Results show a clear link between directionality and acoustic access to the back cavity of the microphone. Furthermore, there was a change in direction of the first-order directionality with reduced height in this back cavity acoustic access. The required configuration for creating an identical directionality for all four frequency bands is investigated along with the influence of reducing the symmetry of the acoustic back cavity access. This paper highlights the overall requirement of considering housing geometries and their influence on acoustic behavior for bio-inspired directional microphones

High-Grade Prostate Cancer: Favorable Results in the Modern Era Regardless of Initial Treatment

Purpose. We performed a retrospective study to determine the outcome of a modern cohort of patients with high-grade (Gleason score ≥ 8) prostate cancer treated with radical prostatectomy, radiation therapy, or hormone therapy. Methods. We identified 404 patients in the South Texas Veteran's Healthcare System Tumor Registry diagnosed with high grade prostate cancer between 1998 and 2008. Mean follow-up was 4.62 ± 2.61 years. End points were biochemical failure-free survival, overall survival, metastasis-free survival, and cancer-specific survival. Results. 5-year overall survival for patients undergoing radical prostatectomy, radiation therapy, and hormone therapy was 88.9%, 76.3%, and 58.9%, respectively. 5-year metastasis-free survival for patients undergoing radical prostatectomy, radiation therapy, and hormone therapy was 96.8%, 96.6%, and 88.4%, respectively, and 5-year cancer-specific survival was 97.2%, 100%, and 89.9%, respectively. Patients with a Gleason score of 10 and pretreatment prostate-specific antigen > 20 ng/mL had decreased 5-year biochemical failure-free and cancer-specific survival. Patients with a pretreatment prostate-specific antigen > 20 ng/mL had decreased 5-year overall survival. Discussion. Even for patients with high-grade disease, the outcome is not as dire in the modern era regardless of primary treatment modality chosen. While there is room for improvement, we should not have a nihilistic impression of how these patients will respond to treatment

Hydrogenation of alkynyl substituted aromatics over rhodium/silica

The cascade reactions of phenylacetylene to ethylcyclohexane and 1-phenyl-1-propyne to propylcyclohexane were studied individually, under deuterium and competitively at 343 K and 3 barg pressure over a Rh/silica catalyst. Both systems gave similar activation energies for alkyne hydrogenation (56 ± 4 kJ mol−1 for phenylacetylene and 50 ± 4 kJ mol−1 for 1-phenyl-1-propyne). Over fresh catalyst the order of reactivity was styrene > phenylacetylene ≫ ethylbenzene. Whereas with the cascade hydrogenation starting with phenylacetylene, styrene hydrogenated much slower phenylacetylene even once all the phenylacetylene was hydrogenated. The activity of ethylbenzene was also reduced in the cascade reaction and after styrene hydrogenation. These reductions in rate were likely due to carbon laydown from phenylacetylene and styrene. Similar behavior was observed with the 1-phenyl-1-propyne cascade. Deuterium experiments revealed similar positive KIEs for phenylacetylene (2.6) and 1-phenyl-1-propyne (2.1). Ethylbenzene hydrogenation/deuteration gave a KIE of 1.6 obtained after styrene hydrogenation in contrast to the inverse KIE of 0.4 found with ethylbenzene hydrogenation/deuteration over a fresh catalyst, indicating a change in rate determining step. Competitive hydrogenation between phenylacetylene and styrene reduced the rate of phenylacetylene hydrogenation but increased selectivity to ethylbenzene suggesting a change in the flux of sub-surface hydrogen. In the competitive reaction between 1-phenyl-1-propyne and propylbenzene, the rate of hydrogenation of 1-phenyl-1-propyne was increased and the rate of alkene isomerization was decreased, likely due to an increase in the hydrogen flux for hydrogenation and a decrease in the hydrogen species active in methylstyrene isomerization

Synthesis of Nm-PHB (nanomelanin-polyhydroxy butyrate) nanocomposite film and its protective effect against biofilm-forming multi drug resistant Staphylococcus aureus

Melanin is a dark brown ubiquitous photosynthetic pigment which have many varied and ever expanding applications in fabrication of radio-protective materials, food packaging, cosmetics and in medicine. In this study, melanin production in a Pseudomonas sp. which was isolated from the marine sponge Tetyrina citirna was optimized employing one-factor at a time experiments and characterized for chemical nature and stability. Following sonication nucleated nanomelanin (Nm) particles were formed and evaluated for antibacterial and antioxidant properties. Nanocomposite film was fabricated using combinations (% w/v) of polyhydroxy butyrate-nanomelanin (PHB: Nm) blended with 1% glycerol. The Nm was found to be spherical in shape with a diameter of 100-140 nm and showed strong antimicrobial activity against both Gram positive and Gram negative bacteria. The Nm-PHB nanocomposite film was homogeneous, smooth, without any cracks, and flexible. XRD and DSC data indicated that the film was crystalline in nature, and was thermostable up to 281.87 degrees C. This study represents the first report on the synthesis of Nm and fabrication of Nm-PHB nanocomposite film which show strong protective effect against multidrug resistant Staphyloccoccus aureus. Thus this Nm-PHB nanocomposite film may find utility as packaging material for food products by protecting the food products from oxidation and bacterial contamination

Extreme call amplitude from near-field acoustic wave coupling in the stridulating water insect Micronecta scholtzi (Micronectinae)

Underwater acoustic transducers, particularly at low frequencies, are beset by problems of scale and inefficiency due to the large wavelengths of sound in water. In insect mating calls, a high call volume is usually desirable, increasing the range of signal transmission and providing a form of advertisement of the signaller's quality to a potential mate; however, the strength of the call is constrained by body size and by the need to avoid predators who may be listening in. Male crickets and water boatmen avoid some of the limitations of body size by exploiting resonant structures, which produce sharply tuned species specific songs, but call frequency and volume remain linked to body size. Recently, the water boatman Micronecta scholtzi was found to circumvent this rule, producing a louder mating call than that of similar, but much larger, Corixa. The resonant structure in Corixidae and Micronectinae is believed to be the trapped air reserves around the insect as it dives, driven by a stridulatory apparatus. However, the method by which energy is transferred from the striated area to the bubble is unknown. Here, we present modelling of a system of near-field coupling of acoustic sources to bubbles showing an exponential increase in sound power gain with decreasing distance that provides a simple solution to the stimulus of the air bubbles in Corixidae and Micronectinae and explains the discrepancy of M. scholtzi's extreme call volume. The findings suggest a possible route to engineered systems using near-field coupling to overcome size constraints in low-frequency (less than 500 Hz) underwater transducers, where the input efficiency of a piezoelectric device can be coupled through the hydrodynamic field to the high radiative efficiency of a near-ideal monopole emitter

Exposure of Candida albicans β (1,3)-glucan is promoted by activation of the Cek1 pathway

Candida albicans is among the most common causes of human fungal infections and is an important source of mortality. C. albicans is able to diminish its detection by innate immune cells through masking of β (1,3)-glucan in the inner cell wall with an outer layer of heavily glycosylated mannoproteins (mannan). However, mutations or drugs that disrupt the cell wall can lead to exposure of β (1,3)-glucan (unmasking) and enhanced detection by innate immune cells through receptors like Dectin-1, the C-type signaling lectin. Previously, our lab showed that the pathway for synthesizing the phospholipid phosphatidylserine (PS) plays a role in β (1,3)-glucan masking. The homozygous PS synthase knockout mutant, cho1Δ/Δ, exhibits increased exposure of β (1,3)-glucan. Several Mitogen Activated Protein Kinase (MAPK) pathways and their upstream Rho-type small GTPases are important for regulating cell wall biogenesis and remodeling. In the cho1Δ/Δ mutant, both the Cek1 and Mkc1 MAPKs are constitutively activated, and they act downstream of the small GTPases Cdc42 and Rho1, respectively. In addition, Cdc42 activity is up-regulated in cho1Δ/Δ. Thus, it was hypothesized that activation of Cdc42 or Rho1 and their downstream kinases cause unmasking. Disruption of MKC1 does not decrease unmasking in cho1Δ/Δ, and hyperactivation of Rho1 in wild-type cells increases unmasking and activation of both Cek1 and Mkc1. Moreover, independent hyperactivation of the MAP kinase kinase kinase Ste11 in wild-type cells leads to Cek1 activation and increased β (1,3)-glucan exposure. Thus, upregulation of the Cek1 MAPK pathway causes unmasking, and may be responsible for unmasking in cho1Δ/Δ

Space Shuttle Program: Automatic rendezvous, proximity operations, and capture (category 3)

The NASA Johnson Space Center is actively pursuing the development and demonstration of capabilities for automatic rendezvous, proximity operations, and capture (AR&C) using the Space Shuttle as the active vehicle. This activity combines the technologies, expertise, tools, and facilities of the JSC Tracking and Communications Division (EE), Navigation, Control and Aeronautics Division (EG), Automation and Robotics Division (ER), and Structures and Mechanics Division (ES) of the Engineering Directorate and the Flight Design and Dynamics Division (DM) of the Mission Operations Directorate. Potential benefits of AR&C include more efficient and repeatable rendezvous, proximity operations, and capture operations; reduced impacts on the target vehicles (e.g., Orbiter RCS plume loads); reduced flight crew work loads; reduced ground support requirements; and reduced operational constraints. This paper documents the current JSC capabilities/tools/facilities for AR&C and describes a proposed plan for a progression of ground demonstrations and flight tests and demonstrations of AR&C capabilities. This plan involves the maturing of existing technologies in tracking and communications; guidance, navigation and control; mechanisms; manipulators; and systems management and integrating them into several evolutionary demonstration stages