Hybrid Research Articles

Hybrid surgery for bilateral lower extremity inflow revascularization

ObjectiveAortobifemoral (ABF) bypass is the preferred method of bilateral inflow revascularization, with axillobifemoral (AXBF) bypass reserved for high-risk patients. Hybrid (HYB) surgery in the form of femorofemoral bypass and retrograde endovascular aortoiliac intervention is increasingly being used to achieve the same goal. This study compared the perioperative outcomes of HYB surgery with traditional surgery for bilateral inflow revascularization. MethodsThe American College of Surgeons National Surgical Quality Improvement Program files for the years 2012 to 2015 were reviewed, and all patients undergoing ABF bypass, AXBF bypass, and HYB surgery (femoral-femoral bypass and retrograde endovascular intervention) were included. Patients' demographics, comorbidities, and outcomes were compared between the three groups. A propensity-matched analysis was subsequently performed to compare HYB surgery with ABF bypass only. The χ2 test and analysis of variance with post hoc analysis were conducted to evaluate between-group differences in risk factors and outcomes. SPSS statistical software (IBM Corp, Armonk, NY) was used. ResultsThere were 1426 patients (ABF bypass, 976; AXBF bypass, 257; HYB surgery, 193). There were significant differences in the three populations of patients, with ABF bypass patients significantly more likely to have age <70 years (ABF bypass, 84.2%; AXBF bypass, 49.8%; HYB surgery, 58%; P < .001) and more likely to be independent (ABF bypass, 98%; AXBF bypass, 89.1%; HYB surgery, 93.2%; P < .001). Patients undergoing AXBF bypass were significantly more likely to be treated for critical limb ischemia (ABF bypass, 46.5%; AXBF bypass, 72.4%; HYB surgery, 51.8%; P < .001) under emergent conditions (ABF bypass, 0.9%; AXBF bypass, 5.1%; HYB surgery, 3.6%; P < .001). There was no difference in mortality between the three groups (P = .178). After propensity matching, a total of 571 patients with ABF bypass were compared with HYB surgery patients. HYB surgery patients had significantly less pneumonia (ABF bypass, 8.7%; HYB surgery, 1.6%; P < .001), unplanned intubation (ABF bypass, 7.7%; HYB surgery, 3.1%; P = .032), cardiac arrest (ABF bypass, 3.7%; HYB surgery, 0.5%; P = .025), transfusion (ABF bypass, 44.4%; HYB surgery, 18.1%; P < .001), and composite morbidity (ABF bypass, 55%; HYB surgery, 32.6%; P < .001). Patients undergoing ABF bypass had significantly higher mortality (ABF bypass, 4.2%; HYB surgery, 1%; P = .043) and 30-day reoperation (ABF bypass, 17.5%; HYB surgery, 9.3%; P = .009) and longer total hospital length of stay (ABF bypass, 9.79 ± 10.69 days; HYB surgery, 5.79 ± 9.72 days; P < .001). There was no difference in major amputation (P = .607) and readmission (P = .495) between the two groups. ConclusionsABF bypass is the most common surgery for bilateral lower extremity revascularization in the American College of Surgeons National Surgical Quality Improvement Program database and continues to have good outcomes. In selected patients, HYB surgery was associated with improved perioperative, 30-day outcomes compared with ABF bypass.

Proteomic analysis of the rice (Oryza officinalis) provides clues on molecular tagging of proteins for brown planthopper resistance

BackgroundAmong various pests, the brown planthopper (BPH) that damages rice is the major destructive pests. Understanding resistance mechanisms is a critical step toward effective control of BPH. This study investigates the proteomics of BPH interactions with three rice cultivars: the first resistant (PR) to BPH, the second susceptible (PS), and the third hybrid (HR) between the two, in order to understand mechanisms of BPH resistance in rice.ResultsOver 4900 proteins were identified from these three rice cultivars using iTRAQ proteomics study. A total of 414, 425 and 470 differentially expressed proteins (DEPs) were detected from PR, PS and HR, respectively, after BPH infestation. Identified DEPs are mainly enriched in categories related with biosynthesis of secondary metabolites, carbon metabolism, and glyoxylate and dicarboxylate metabolism. A two-component response regulator protein (ORR22) may participate in the early signal transduction after BPH infestation. In the case of the resistant rice cultivar (PR), 6 DEPs, i.e. two lipoxygenases (LOXs), a lipase, two dirigent proteins (DIRs) and an Ent-cassa-12,15-diene synthase (OsDTC1) are related to inheritable BPH resistance. A heat shock protein (HSP20) may take part in the physiological response to BPH infestation, making it a potential target for marker-assisted selection (MAS) of rice. Quantitative real-time polymerase chain reaction (qRT-PCR) revealed eight genes encoding various metabolic proteins involved in BPH resistance. During grain development the expressions of these genes varied at the transcriptional and translational levels.ConclusionsThis study provides comprehensive details of key proteins under compatible and incompatible interactions during BPH infestation, which will be useful for further investigation of the molecular basis of rice resistance to BPH and for breeding BPH-resistant rice cultivars.

Radar Reflectivity and Altitude Distributions of Lightning as a Function of IC, CG, and HY Flashes: Implications for LNOx Production

AbstractTwo dimensional (2‐D) histogram distributions of lightning flashes relative to radar reflectivity and altitude were created using a total of 41,180 intercloud/intracloud (IC) flashes, 3,326 cloud‐to‐ground (CG) flashes, and 4,349 hybrid (HY) flashes that originated in multicells; 111,479 IC flashes, 8,588 CG flashes, and 11,699 HY flashes that originated in mesoscale convective systems; and 91,283 IC flashes, 3,023 CG flashes, and 7,872 HY flashes that originated in supercells that occurred over northern Alabama and southern Tennessee. It was shown that although CG flashes initiate and propagate at the same altitude irrespective of storm type, IC flashes could have differences of up to 10 °C, while for HY flashes these differences increased to up to 20 °C relative to storm type. Further, IC, CG, and HY flashes propagated in lower reflectivities than where they initiated, while CG flashes initiated and propagated within higher reflectivities than IC and HY flashes. HY flashes were also twice as large as IC flashes and ~40% larger than CG flashes, and flashes that originated in mesoscale convective systems had larger overall sizes as compared to multicells and supercells. When comparing the new 2‐D histogram distributions to the legacy distributions used for the calculation of lightning‐produced nitrogen oxides (LNOx), it was shown that the new distributions perform much better, with higher Pearson product moment correlation coefficient values and much lower root‐mean‐square errors. These new distributions are thus more appropriate to use when modeling LNOx and will lead to more accurate LNOx estimations than using the legacy distributions.

Comparing biofloc, clear-water, and hybrid nursery systems (Part I): Shrimp (Litopenaeus vannamei) production, water quality, and stable isotope dynamics

Indoor, intensive, nursery-based recirculating aquaculture systems (RAS) can provide high-quality juvenile shrimp for indoor or pond-based production systems in a biosecure manner. However, it is unclear what type of RAS is most appropriate for indoor shrimp nurseries. This study compared three types of RAS nurseries: biofloc (BF), clear-water (CW), and hybrid (HY). Each treatment included four, randomly assigned 160 L (0.35-m2) tanks that were stocked with 3000 post-larvae shrimp m−3. The post-larvae (PL10) shrimp had an initial average weight of 7 ± 0.0 mg and were grown for 48 days. The BF tanks included external settling chambers as the only filtration mechanism. The CW tanks had settling chambers, foam fractionators, and external biofilters to fully clarify the water and process nitrogenous waste. Hybrid tanks included settling chambers, and external biofilters to maintain some suspended solids along with external biofiltration. Overall, the CW treatment had significantly higher dissolved oxygen (DO) and pH levels than the BF and HY systems. The HY treatment had significantly higher DO than the BF treatment. Nitrite concentration was significantly higher in the HY treatment than the CW treatment. Turbidity in the BF treatment was significantly higher than the other treatments. On the final sample date, the BF treatment had significantly higher nitrite and nitrate concentrations than the other treatments. Differences between treatments in terms of shrimp survival, mean harvest weight, specific growth rate, and feed conversion ratio were not significant. The final weight of the shrimp at 48 days for the BF, CW, and HY were 670 mg, 640 mg, and 590 mg respectively. A stable isotope mixing model indicated that, in the BF treatment, 13% of the C and 34% of the N in harvested shrimp tissue may have originated from biofloc material, signifying some nutrient recycling. The nitrification process was more effective with the inclusion of an external biofilter. All three system types appear suitable for RAS shrimp nursery production although consideration should be given to water quality consistency and filtration costs.

Comparing biofloc, clear-water, and hybrid recirculating nursery systems (Part II): Tilapia (Oreochromis niloticus) production and water quality dynamics

Indoor, recirculating aquaculture systems (RAS) can be used to nurse tilapia fry in a biosecure environment to support a variety of production systems; however, it is not understood what type of RAS may be most appropriate for this task. Clear-water and biofloc systems have advantages and disadvantages; hybrid systems combining positive features of both could optimize animal performance and minimize production costs. In this study, four replicate 160-L tanks were randomly assigned to clear-water (CW), biofloc (BF), or hybrid (HY) treatments. CW tanks had a settling chamber, foam fractionator, and external biofilter containing biomedia. BF tanks only had a settling chamber, and HY tanks used a settling chamber and external biofilter. Tilapia (Oreochromis niloticus) were stocked at 55 per tank (305 fish/m3) at 0.17 g average weight. Total Ammonia Nitrogen (TAN) and nitrate were not significantly different between systems. Nitrite was significantly higher in BF compared to CW and HY systems during the last 4 weeks of the study. Turbidity was significantly higher in BF systems versus other treatments. Tilapia in HY systems had significantly higher average weight and specific growth rate compared to BF. Tilapia in BF systems had significantly higher feed conversion ratios and significantly lower harvest biomass versus other treatments. Diminished performance in BF systems likely resulted from inferior water quality conditions. The results indicate that CW or HY systems may be a better choice for tilapia nurseries than chemoautotrophic BF systems due to the short term periods in which nurseries operate and the volitility of nitrification in biofloc systems.

Early and Late Reoperation Rates With Various MIS Techniques for Adult Spinal Deformity Correction.

Study Design:A multicenter retrospective review of an adult spinal deformity database.Objective:We aimed to characterize reoperation rates and etiologies of adult spinal deformity surgery with circumferential minimally invasive surgery (cMIS) and hybrid (HYB) techniques.Methods:Inclusion criteria were age ≥18 years, and one of the following: coronal Cobb >20°, sagittal vertical axis >5 cm, pelvic tilt >20°, and pelvic incidence-lumbar lordosis >10°. Patients with either cMIS or HYB surgery, ≥3 spinal levels treated with 2-year minimum follow-up were included.Results:A total of 133 patients met inclusion for this study (65 HYB and 68 cMIS). Junctional failure (13.8%) was the most common reason for reoperation in the HYB group, while fixation failure was the most common reason in the cMIS group (14.7%). There was a higher incidence of proximal junctional failure (PJF) than distal junctional failure (DJF) within HYB (12.3% vs 3.1%), but no significant differences in PJF or DJF rates when compared to cMIS. Early (<30 days) reoperations were less common (cMIS = 1.5%; HYB = 6.1%) than late (>30 days) reoperations (cMIS = 26.5%; HYB = 27.7%), but early reoperations were more common in the HYB group after propensity matching, largely due to infection rates (10.8% vs 0%, P = .04).Conclusions:Adult spinal deformity correction with cMIS and HYB techniques result in overall reoperation rates of 27.9% and 33.8%, respectively, at minimum 2-year follow-up. Junctional failures are more common after HYB approaches, while pseudarthrosis/fixation failures happen more often with cMIS techniques. Early reoperations were less common than later returns to the operating room in both groups, but cMIS demonstrated less risk of infection and early reoperation when compared with the HYB group.

Post-stratified change estimation for large-area forest biomass using repeated ALS strip sampling

Post-stratified model-assisted (MA) and hybrid (HY) estimators are used with repeated airborne laser scanning (ALS) strip sampling and national forest inventory field data for stratum-wise and overall estimation of aboveground biomass (AGB) stock and change. The study area covered the southern portion of the Hedmark County in Norway. Both MA and HY estimation substantially reduced the uncertainty in AGB change when compared with estimation using the field survey only. Relative efficiencies (relative variance) of 4.15 (MA) and 3.36 (HY) for overall estimates were found. The results suggest the MA estimator for single-time estimation and the HY as more appropriate for change estimation by cover class. With the HY estimator, a nested post-stratification scheme is demonstrated, combining cover classes with change classes, which enables detailed reporting for change according to cause within each cover class, and has the potential to improve the estimation precision. Finally, parametric bootstrapping is demonstrated as an empirical alternative to estimate the model-error component in the HY estimator. The model error estimated with parametric bootstrapping converged to the analytically determined value of the HY estimator within 1000 bootstrap samples.

Structure and Properties of Self-Assembling Low-Dimensional Hy brid Materials: the Case of Cadmium Halides in Polyvinyl Alcohol

Structure and Properties of Self-Assembling Low-Dimensional Hy brid Materials: the Case of Cadmium Halides in Polyvinyl Alcohol

An efficient sparse matrix‐vector multiplication on CUDA‐enabled graphic processing units for finite element method simulations

SummaryFinite element method (FEM) is a well‐developed method to solve real‐world problems that can be modeled with differential equations. As the available computational power increases, complex and large‐size problems can be solved using FEM, which typically involves multiple degrees of freedom (DOF) per node, high order of elements, and an iterative solver requiring several sparse matrix‐vector multiplication operations. In this work, a new storage scheme is proposed for sparse matrices arising from FEM simulations with multiple DOF per node. A sparse matrix‐vector multiplication kernel and its variants using the proposed scheme are also given for CUDA‐enabled GPUs. The proposed scheme and the kernels rely on the mesh connectivity data from FEM discretization and the number of DOF per node. The proposed kernel performance was evaluated on seven test matrices for double‐precision floating point operations. The performance analysis showed that the proposed GPU kernel outperforms the ELLPACK (ELL) and CUSPARSE Hybrid (HYB) format GPU kernels by an average of 42% and 32%, respectively, on a Tesla K20c card. Copyright © 2016 John Wiley &amp; Sons, Ltd.

A Combined Nissen Plus Hill Hybrid Repair for Paraesophageal Hernia Improves Clinical Outcomes and Reduces Long-Term Recurrences Compared with Laparoscopic Nissen Alone

IntroductionWe compared clinical and objective outcomes of combined Nissen-Hill hybrid (HYB) to Nissen fundoplication (LNF) for repair of paraesophageal hernia (PEH). MethodsThis study is a single-institution retrospective chart review of prospectively collected data for consecutive patients undergoing PEH repair from 2006 to 2015 with at least 6 months of follow-up. Quality of life metrics (QOLRAD, HRQL, and dysphagia), manometry, radiographic imaging, and pH testing were administered pre- and postoperatively. ResultsWith 319 repairs (HYB = 141, LNF = 178), the groups were comparable in age and gender, but HYB had a higher BMI (30.95 vs 29.27, p < 0.05), larger hernia (6 vs 5 cm, p < 0.05), and more Barrett’s esophagus (42 vs 29, p < 0.05). At a median follow-up of 22 months, DeMeester scores were equivalent but PPI use was higher in the LNF group. All three quality of life scores were better for HYB: GERD-HRQL 3.75 vs 7.49, p = 0.01; QOLRAD 6.59 vs 6.23, p = 0.04; and swallowing 40.71 vs 36.47, p = 0.01. At a median follow-up of 60 months (HYB = 39, LNF = 31), anatomic recurrences and reoperations were lower for HYB: 5 vs 45 % (p < 0.05), 2.6 vs 9.7 % (p = 0.2). ConclusionCombining Nissen and Hill for PEH repair appears to result in better quality of life and fewer recurrences compared to LNF.

Proposal of Hybrid Type Active Magnetic Bearing for Turbo Machinery

New Hybrid (HB) type Active Magnetic Bearing (AMB) is proposed in this paper. It is intended to apply to high speed turbo machinery. This magnetic bearing is easily controlled by a standard linear power amplifier. The proposed magnetic bearing is analyzed and designed through Finite Element Method (FEM). The designed characteristics are compared with the standard electro-magnet type magnetic bearing. The results show good characteristics of high efficiency, good dynamic property and easy manufacturing. The proposed magnetic bearing is fabricated and the simple tests are carried out.

Cardiac Magnetic Resonance Assessment of Ventricular and Vascular Properties after Stage 2 Palliation for Hypoplastic Left Heart Syndrome: A Dual Center Study Comparing the Norwood and Hybrid Approach

Objectives: Stage 1 palliation of hypoplastic left heart syndrome (HLHS) can be achieved either by the Norwood (NW) procedure or the Hybrid (HY) approach. These procedures result in different hemodynamic profiles that may have an impact on ventricular performance and vascular properties in the long term. Accordingly, the aim of this study was to compare CMR data of HLHS patients after stage 2 who underwent either a NW or the HY strategy in two European centers.

Varied Growth Response of Cogongrass Ecotypes to Elevated CO2.

Cogongrass [Imperata cylindrica (L.) P. Beauv] is an invasive C4 perennial grass which is listed as one of the top ten worst weeds in the world and is a major problem in the Southeast US. Five cogongrass ecotypes [Florida (FL), Hybrid (HY), Louisiana (LA), Mobile (MB), and North Alabama (NA)] collected across the Southeast and a red-tip (RT) ornamental variety were container grown for 6 months in open top chambers under ambient and elevated (ambient plus 200 ppm) atmospheric CO2. Elevated CO2 increased average dry weight (13%) which is typical for grasses. Elevated CO2 increased height growth and both nitrogen and water use efficiencies, but lowered tissue nitrogen concentration; again, these are typical plant responses to elevated CO2. The HY ecotype tended to exhibit the greatest growth (followed by LA, NA, and FL ecotypes) whiles the RT and MB ecotypes were smallest. Interactions of CO2 with ecotype generally showed that the HY, LA, FL, and/or NA ecotypes showed a positive response to CO2 while the MB and RT ecotypes did not. Cogongrass is a problematic invasive weed in the southeastern U.S. and some ecotypes may become more so as atmospheric CO2 continues to rise.

Flow-induced vibrations of two side-by-side circular cylinders: Asymmetric vibration, symmetry hysteresis and near-wake patterns

The immersed boundary method was utilised to numerically investigate the flow-induced vibrations (FIV) of two elastically mounted side-by-side circular cylinders in a uniform flow with low Reynolds numbers. Six distinct near-wake patterns were observed; the irregular (IR) pattern, the in-phase synchronized (IS) pattern, the anti-phase synchronized (AS) pattern, the biased anti-phase synchronized (BAS) pattern, the out-of-phase flip-flopping (OFF) pattern, and the hybrid (HB) pattern. A detailed analysis on the asymmetric vibration and symmetry hysteresis phenomena was conducted by focusing on the near-wake patterns and the interaction between the cylinders. Results show that the asymmetric vibrations of the cylinders are closely related with the stably biased gap flow and the resulting narrow-wide near-wake pattern. While the symmetry hysteresis is caused by the coexistence of two distinct near-wake patterns – the IS and the BAS patterns. The transition processes of BAS to IS and IS to BAS were illustrated by using the long-time histories of the lift coefficients, the combined lift coefficient and the phase differences of lift and displacement. Results on hydrodynamic forces and the vibration responses show that the HB pattern is a combination of IS, OFF and AS patterns with a very long period.

电化学法控制聚吡咯/α-磷酸锆/碳毡电极去除水中低浓度铅离子

采用循环伏安法在水相中制备了电活性聚吡咯/α-磷酸锆（PPy/α-Zr P）有机-无机杂化膜,通过FT-IR、XRD、XPS对电活性PPy/α-Zr P杂化膜进行表征.将制备在碳毡（PTCF）基体上的电活性PPy/α-Zr P膜电极（聚吡咯/α-磷酸锆/碳毡电极,PPy/α-Zr P/PTCF）用于电控离子交换去除废水中的铅离子.通过对PPy/α-Zr P膜电极施加氧化还原电位来调节电活性组分PPy/α-Zr P的氧化还原状态,使废水中的铅离子能够快速置入和释放.在10 mg·L-1的Pb（II）水溶液中,膜电极对铅离子的去除效率为单纯离子交换的1.8倍,膜电极的吸附量为单纯离子交换的2倍,表明该膜电极在电控离子交换条件下对铅离子具有较强的去除效率和更高的吸附容量.吸附过程符合准二级动力学模型,电控离子交换的准二级吸附速率常数k2（0.6142 g·mg-1·h-1）明显高于单纯离子交换（0.2632g·mg-1·h-1）.

Does Minimally Invasive Percutaneous Posterior Instrumentation Reduce Risk of Proximal Junctional Kyphosis in Adult Spinal Deformity Surgery? A Propensity-Matched Cohort Analysis.

Proximal junctional kyphosis (PJK) is a known complication after spinal deformity surgery. One potential cause is disruption of posterior muscular tension band during pedicle screw placement. To investigate the effect of minimally invasive surgery (MIS) on PJK. A multicenter database of patients who underwent deformity surgery was propensity matched for pelvic incidence (PI) to lumbar lordosis (LL) mismatch and change in LL. Radiographic PJK was defined as proximal junctional angle >10°. Sixty-eight patients made up the circumferential MIS (cMIS) group, and 68 were in the hybrid (HYB) surgery group (open screw placement). Preoperatively, there was no difference in age, body mass index, PI-LL mismatch, or sagittal vertical axis. The mean number of levels treated posteriorly was 4.7 for cMIS and 8.2 for HYB (P < .001). Both had improved LL and PI-LL mismatch postoperatively. Sagittal vertical axis remained physiological for the cMIS and HYB groups. Oswestry Disability Index scores were significantly improved in both groups. Radiographic PJK developed in 31.3% of the cMIS and 52.9% of the HYB group (P = .01). Reoperation for PJK was 4.5% for the cMIS and 10.3% for the HYB group (P = .20). Subgroup analysis for patients undergoing similar levels of posterior instrumentation in the cMIS and HYB groups found a PJK rate of 48.1% and 53.8% (P = .68) and a reoperation rate of 11.1% and 19.2%, respectively (P = .41). Mean follow-up was 32.8 months. Overall rates of radiographic PJK and reoperation for PJK were not significantly decreased with MIS pedicle screw placement. However, a larger comparative study is needed to confirm that MIS pedicle screw placement does not affect PJK.

Impact of Training System and Pruning Severity on Yield, Fruit Composition, and Vegetative Growth of ‘Niagara’ Grapevines in Michigan

‘Niagara’ (Vitis labruscana Bailey) vines were evaluated for 4 years, from 2000 to 2003 in a commercial vineyard in Scottdale, MI. Vines were trained as Hudson River Umbrella (HRU), umbrella Kniffen (UK), and Hybrid (HYB) and pruned for 4 years at four pruning levels (20, 40, 80, or 120 nodes/vine) and minimally pruned or hedge pruned mechanically. Node levels above 80 nodes decreased several yield components, such as cluster and berry weight. Reduction in yield and sugar components was obtained with pruning levels above 80 nodes per vine and related to a decrease in cluster and berry weight as well as a decrease in bud fruitfulness (productivity index). As number of nodes retained increased, vine size, cluster weight, berry weight, percent soluble solids, and pH decreased, while yield, cluster number, and leaf area at veraison increased. Yield components, vine size, and productivity were optimum at 20 and 40 nodes retained, but these node levels produce unacceptable low yields for economically viable juice grape production in Michigan. Therefore, retaining 80 fixed nodes produced sustainable production, without compromising vine health or long-term vineyard sustainability. There were no differences between HRU, UK, and HYB on vegetative or reproductive parameters or on fruit composition. Thus, the choice of training system—HRU, UK, or HYB—should be based on specific grower and vineyard needs.

Practical Realization of Apertureless Scanning Near-field Optical Microscopy Using Hybrid Mode Atomic Force Microscopy

ABSTRACTThe local detection of optical response at the sub-wavelength scale on a materials’ surface is an invaluable characterization capability of apertureless scanning near-field optical microscopy (ASNOM). The technique is traditionally realized in amplitude modulation (AM) AFM mode. We have expanded this method by employing an alternative scheme for the detection of the near-field and far-field responses with the use of Hybrid (HD) AFM mode. In HD mode the sample is brought to the intermittent contact with the tip in a periodic oscillation at a frequency (1-2 kHz) much smaller than the probe resonance. In every oscillation cycle the probe deflection to a set-point value is used for surface profiling. For optical measurements the metal coated AFM tip was top-illuminated by visible laser. Simultaneously with surface profiling the light scattered from tip-sample junction was collected by a sensitive photomultiplier (PMT). The homodyne optical signal detection scheme was applied to discriminate near- and far-field optical components. Our method was verified by the studies of various materials (semiconductors, metals, polymers, etc.). The presented results show that the contrast of ASNOM images can be used for compositional mapping of heterogeneous systems.

Environmentally Friendly Hybrid Power System for Cultivators

Purpose: In this study, a hybrid power system was developed for agricultural machines with a 20-KW output capacity, and it was attached to a multi-purpose cultivator to improve the performance of the cultivator, which was evaluated using output tests. Methods: The hybrid system combined heterogeneous sources: an internal-combustion engine and an electric power motor. In addition, a power splitter was developed to simplify the power transmission structure. The cultivator using the hybrid system was designed to have increased fuel efficiency and output power and reduced exhaust gas emissions, while maintaining the functions of existing cultivators. Results: The fuel consumption for driving the cultivator in the hybrid engine vehicle (HEV) mode was 341 g/KWh, which was 36% less than the consumption in the engine (ENG) mode for the same load. The maximum power take off output of the hybrid power system was 12.7 KW, which was 38% more than the output of the internal-combustion engine. In the HEV mode, harmful exhaust gas emissions were reduced; i.e., CO emissions were reduced by 36~41% and NOx emissions were reduced by 27~51% compared to the corresponding emissions in the ENG mode. Conclusions: The hybrid power system improved the fuel efficiency and reduced exhaust gas emissions in agricultural machinery. Lower exhaust gas emissions of the hybr id system have considerable advantages in closed work environments such as crop production facilities; therefore, agricultural machinery with less exhaust gas emissions should be commercialized. However, the high manufacturing cost and complexity of the proposed system are challenges which need to be solved in the future.

ESTIMATED AND ANALYSIS OF THE RELATIONSHIP BETWEEN THE ENDOGENOUS AND EXOGENOUS VARIABLES USING FUZZY SEMI-PARAMETRIC SAMPLE SELECTION MODEL

An important progress within the last decade in the development of the selectivity model approach to overcome the inconsistent results if the distributi onal assumptions of the errors terms are made this problem is through the use of semi-parametric method. However, the uncertainties and ambiguities exist in the mod els, particularly the relationship between the endogenou s and exogenous variables. A new framework of the relationship between the endogenous and exogenous variables of semi-parametric sample selection model using the concept of fuzzy modelling is introduced. Through this approach, a flexible fuzzy concept hy brid with the semi-parametric sample selection models known as Fuzzy Semi-Parametric Sample Selection Model (FSPSSM). The elements of vagueness and uncertainty in the models are represented in the model construction, as a way of increasing the available information to produce a more accurate model. This led to the development of the convergence theorem presented in the form of triangular fuzzy numbers to be use d in the model. Besides that, proofs of the theorems are presented. An algorithm using the concept of fuzzy modelling is developed. The effectiveness of the es timators for this model is investigated. Monte Carl o simulation revealed that consistency depends on ban dwidth parameter. When bandwidth parameters, c are increased from 0.1, 0.5, 0.75 and 1 as the numbers of N increased (from 100 to 200 and increased to 50 0), the values of mean approaches (closed to) the real para meter. Through the bandwidth parameter also reveals that the estimated parameter is efficient, i.e., the S.D , MSE and RMSE values become smaller as N increased. In particular, the estimated parameter becomes consist ent and efficient as the bandwidth parameters appro aches to infinity, c→∞ as the number of observations, n tend to infinity, n→∞.