Average Operating Speed Research Articles

Size-Adjustable Microdroplets Generation Based on Microinjection

Microinjection is a promising tool for microdroplet generation, while the microinjection for microdroplets generation still remains a challenging issue due to the Laplace pressure at the micropipette opening. Here, we apply a simple and robust substrate-contacting microinjection method to microdroplet generation, presenting a size-adjustable microdroplets generation method based on a critical injection (CI) model. Firstly, the micropipette is adjusted to a preset injection pressure. Secondly, the micropipette is moved down to contact the substrate, then, the Laplace pressure in the droplet is no longer relevant and the liquid flows out in time. The liquid constantly flows out until the micropipette is lifted, ending the substrate-contacting situation, which results in the recovery of the Laplace pressure at the micropipette opening, and the liquid injection is terminated. We carry out five groups of experiments whereupon 1600 images are captured within each group and the microdroplet radius of each image is detected. Then we determine the relationship among microdroplet radius, radius at the micropipette opening, time, and pressure, and, two more experiments are conducted to verify the relationship. To verify the effectiveness of the substrate-contacting method and the relationship, we conducted two experiments with six desired microdroplet radii are set in each experiment, by adjusting the injection time with a given pressure, and adjusting the injection pressure with a given time. Then, six arrays of microdroplets are obtained in each experiment. The results of the experiments show that the standard errors of the microdroplet radii are less than 2% and the experimental errors fall in the range of ±5%. The average operating speed is 20 microdroplets/min and the minimum radius of the microdroplets is 25 μm. This method has a simple experimental setup that enables easy manipulation and lower cost.

Heuristic urban transportation network design method, a multilayer coevolution approach

The design of urban transportation networks plays a key role in the urban planning process, and the coevolution of urban networks has recently garnered significant attention in literature. However, most of these recent articles are based on networks that are essentially planar. In this research, we propose a heuristic multilayer urban network coevolution model with lower layer network and upper layer network that are associated with growth and stimulate one another. We first use the relative neighbourhood graph and the Gabriel graph to simulate the structure of rail and road networks, respectively. With simulation we find that when a specific number of nodes are added, the total travel cost ratio between an expanded network and the initial lower layer network has the lowest value. The cooperation strength Λ and the changeable parameter average operation speed ratio Θ show that transit users’ route choices change dramatically through the coevolution process and that their decisions, in turn, affect the multilayer network structure. We also note that the simulated relation between the Gini coefficient of the betweenness centrality, Θ and Λ have an optimal point for network design. This research could inspire the analysis of urban network topology features and the assessment of urban growth trends.

Development of Water Application Attachment on Seed Drill for Dry Land Farming

Dry lands contribute 42% of the total food grain production of India. These areas produce 75% of pulses and more than 90% of sorghum, millet and groundnut from arid and semi-arid regions. Thus, dry lands/rainfed farming plays a dominant role in agricultural production. This target cannot be realized from irrigated areas alone as the irrigation potential is only for 178 million hectares. Therefore, an appropriate technology has to be developed for dry land farming. Due to dependency on rains the sowing is often delayed in dry land area which substantially reduces the yield of crop. A water application mechanism thus designed and developed wherein water will be given to the seed at the time of sowing. This will help farmer to sow crop on time, which will help to increase the production by attaining proper germination of crop at the time of sowing. The effective field capacity of water application attachment on seed drill was observed 0.420 ha/h at average operating speed of 2.5 km/h. The field efficiency calculated was 70%. Seed germination per cent in water application attachment on seed drill was 5.60% higher than normal seed drill with no attachment. Yield in water application attachment on seed drill was 16.74% higher than seed drill with no attachment.

Optimal Fleet Size and Fare Setting in Emerging Taxi Markets with Stochastic Demand

AbstractThe emerging taxi services, for instance, Uber and Lyft, are challenging traditional fully regulated taxi markets. Transportation agencies are spending significant efforts to understand the optimal pricing and fleet size taxis that are efficient for a given urban area. This study develops a modeling framework for studying a decentralized equilibrium based market study where the fare is strictly regulated by a taxi commission. The nature of demand‐supply equilibria with stochastic demand are discussed to determine optimal development strategies, for instance, number of issued licenses and fare setting. Two Stackelberg games are formulated to specify leader‐follower relationships between transportation authorities and and the followers — taxi drivers and passengers. An iterative approach is designed to simulate the games and solve corresponding mathematical optimization problems. The case study is based on New York City data which shows that the taxi market may be oversupplied and underpriced, which confirms findings from other studies and price hikes in 2012. Furthermore, different development strategies are proposed based on two Stackelberg games to respond to intended taxi system changes, such as price and quantity elasticity of taxi demand, levels of demand variance, average taxi operation speed, passengers' waiting time value, and taxi service coverage. The results have important implications in determining development strategies for taxi industry with emerging taxi services, stochastic demand, and the rapidly changing environment.

Analysis of Geometric Design Impacts on Vehicle Operating Speed on Two-Lane Rural Roads

The rural road level of service quality has highly related to the vehicles operating speed. The vehicle operating speed has been generally influenced by geometric design characteristics. Previous studies have constructed various analytical models to measure the effect of miscellaneous geometric design variables on vehicle operating speed. This study investigates the main effect of road slopes and its interaction with other variables in Two-Lane rural roads. The vehicles operating speed in 42 sections of Two-Lane rural roads in north of Iran, a recreation area, has been recorded by video. The obtained films are analysed by image processing and operating speeds are measured by an appropriate software with acceptable precision. The distribution of vehicle speed along tangent sections was analysed and it was found speed had normal distribution. So it had two parameters: mean and variance. The relation between these two parameters and geometric characteristics of tangent sections was studied. The results show that the interaction between vehicle classification (passenger car or heavy vehicle) with slope has been significant parameter. Moreover, the initial speed of vehicle at start of tangent section is a significant parameter. This result demonstrates the effect of previous geometric section on vehicle speed. The proposed models are validated by the standard error of estimate and observation versus estimation graph. The models will help road designer to estimate the average operating speed of vehicles along tangent sections and useful for policy makers to enact policies to control vehicles operating speed. The estimated speed can be helpful for analysis the safety of road concepts such as design consistency.

Performance evaluation of reaper-binder in rice crop

Field performance of reaper-binder was assessed in rice crop and compared with manual method of harvesting by sickle at farmer's field under farm implements and machinery scheme during Rabi 2013. The effective field capacity of the reaper-binder was found 0.294ha h -1 with a field efficiency of 67 per cent at an average operating speed of 3.6 kmph compared to 0.025 ha h -1 for manual harvesting. The fuel consumption was found 5.27 l ha -1 . Labour requirements for mechanical and manual harvesting were 36 and 176 man-h ha -1 , respectively. The harvesting losses for mechanical and manual harvesting were 1.44 and 1.88 per cent, respectively. The cost of harvesting operation was Rs.5500/ha for manual harvesting and Rs.2241/ha for mechanical harvesting. The harvesting cost of reaper binder was reduced by 40.74 per cent compared to manual harvesting method with sickle. The feedback of machine operation was collected by some farmer's at the time of harvesting and the performance of the reaper-binder at the farm was satisfactory.

Impact of Pedestrian Traffic on Saturation Rate of Protected Left-Turn at Urban Intersections

Heavily congested intersections in metropolitan areas in China are facing unique problems due to high travel demand and a high degree of traffic law violations. Based on a study conducted by the authors of this paper, 93% of left-turn vehicles turning left in these areas were slowed in order to avoid conflict with pedestrians. Intertwined pedestrian and vehicular flows can significantly reduce the capacity of exclusive left-turn lane group through reducing saturation flow rate, which increases the congestion at intersections. This paper investigates how the saturation flow rate of exclusive left-turn lane group is affected by the characteristics of pedestrian flow. By analyzing the imagery data collected by video cameras installed at intersections, the research team is able to obtain the characteristics of both vehicular and pedestrian flows, such as speed and spatial locations. The average operating speed at the saturation flow rate with and without pedestrian traffic is used as a direct measurement to evaluate the effect of pedestrians. Based on the statistical analysis, the paper concludes that saturation flow rate is mainly affected by the position of pedestrian in the crosswalk (inside or outside of left-turn vehicle’s trajectory), and the distance between the vehicle and pedestrians. In general, when the distance is less than four meters, the smaller the distance between vehicle and pedestrians, the larger the impact. However, there is no significant impact when the distance is larger than four meters. To accurately quantify the effect, the degree of pedestrian-vehicle impact is defined in four levels. The results show that the difference in the saturation flow rate between the best and the worst level could be 15.7%, which clearly indicates how important it is to enforce pedestrian crossing behavior.

DESIGN AND DEVELOPMENT OF A LOW COST MOUNTED TYPE SINGLE LEG SUBSOILER

Free movement of air in the soil and good drainage are necessary for good crop yields.Modem tractors and machinery are partly responsible for soil compaction and soil pans.Subsoilers are used to break compacted soil, allowing free passage of air and water. Forconducting this important operation in crop production, suitable Subsoiler does not existin Sri Lanka. However without proper land preparation, higher yield of crop productionby applying other input cannot be expected. Therefore fields should be subsoiled time totime at right angles to the intended direction of ploughing. Sometimes fanners useexpensive, un tested, imported Ploughs for this purpose. The commercial ploughs used inmany developed countries, are beyond the financial capabilities of local paddy farmers.Properly designed subsoilers are usually mounted on the tractor and consist of a strongframe with one or more legs. Each leg has a replaceable point. Working depth isnormally from 30 to SOcmand spacing between passes is from 0.5 to 2m. Subsoiling isbest carried out after the cereal harvest when the soil is dry.Considering the above facts, a low cost suitable Subsoiler for four wheel tractors wasdesigned and constructed after testing first model Subsoiler in the field and implementingnecessary modificationsAn experiment was conducted in the paddy field to compare the performances of thedeveloped Subsoiler. The result shows that the effective field capacity, effective workingwidth, ploughing depth, travel reduction. average operation speed, and Cost ofproduction of Subsoiler were 0.2 ha/hr, O.Sm,0.3m, 60/0, 1.6 km/hr, SOOORsrespectively.The result shows that the overall field performances of designed Subsoiler wassatisfactory.

Energy conservation for international dry bulk carriers via vessel speed reduction

Abstract This study uses an activity-based method to investigate the fuel consumption and corresponding CO 2 emissions of Capesize, Panamax, Supramax, and Handysize dry bulk carriers. The emission and energy reductions are estimated for speed reductions of 10%, 20%, and 30%. The CATCH (cost of averting a tonne of CO 2 —eq heating) model is applied to evaluate the cost efficiency of speed reduction. Results show that speed reductions of 10%, 20%, and 30% reduce fuel consumption by 27.1%, 48.8%, and 60.3% and CO 2 emissions by 19%, 36%, and 51%, respectively. Speed reduction leads to emission reductions, with greater reductions for larger ships. CATCH values are positive, indicating that reducing speed increases cost. Line C3 of Capesize is used to determine the optimal ship number and operational speed under energy conservation. The minimum number of vessels in service is 9, with an average operational speed of 14.53 knots and one port call per week. If speed is reduced by 10%, 20%, and 30%, one, two, and four additional ships are needed, respectively.

New Consistency Index Based on Inertial Operating Speed

The occurrence of road crashes depends on several factors, with design consistency (i.e., conformance of highway geometry to drivers' expectations) being one of the most important. A new consistency model for evaluating the performance of tangent-to-curve transitions on two-lane rural roads was developed. This model was based on the inertial consistency index (ICI) defined for each transition. The ICI was calculated at the beginning point of the curve as the difference between the average operating speed on the previous 1-km road segment (inertial operating speed) and the actual operating speed at this point. For the calibration of the ICI and its thresholds, 88 road segments, which included 1,686 tangent-to-curve transitions, were studied. The relationship between those results and the crash rate associated with each transition was analyzed. The results showed that the higher the ICI was, the higher the crash rate; thus, the probability of accidents increased. Similar results were obtained from the study of the relationship between the ICI and the weighted average crash rate of the corresponding group of transitions. A graphical and statistical analysis established that road consistency might be considered good when the ICI was lower than 10 km/h, poor when the ICI was higher than 20 km/h, and fair otherwise. A validation process that considered 20 road segments was performed. The ICI values obtained were highly correlated to the number of crashes that had occurred at the analyzed transitions. Thus, the ICI and its consistency thresholds resulted in a new approach for evaluation of consistency.

Use of speed profile as surrogate measure: Effect of traffic calming devices on crosstown road safety performance

Urban road safety management is usually characterized by the lack of sufficient, good quality crash data and low budgets to obtain it even though many traffic accidents occur there. For example, 54 percent of road crashes in Spain take place in urban areas, and 10 percent of urban fatal crashes occur on crosstown roads, which are rural roads that traverse small communities. Traffic calming measures (TCMs) are often implemented on these parts of rural roads that traverse small communities in order to reduce both the frequency and severity of crashes by lowering speeds, but evaluation of their effectiveness has been limited. The objective of this study was to develop a methodology using continuous speed profiles to evaluate the safety effectiveness of TCMs on crosstown roads as part of an integrated system in the absence of historical data. Given the strong relationship between speed and crash experience, safety performance can be related to speed. Consequently, speed can be used indirectly as a surrogate safety measure in the absence of crash and speed data.Two indexes were defined in this study as surrogate safety measures based on the continuous speed profile: Ra and Ea. Ra represents the absolute accumulated speed variations relative to the average speed and is inversely related to accumulated speed uniformity; and Ea represents the accumulated speed variations above the speed limit and is directly related to accumulated speeding. Naturalistic data were collected using GPS trackers for 12 scenarios with different TCM spacings. Then, the indexes were applied to individual observed speed profiles (individual analysis) as well as the operating speed profile (global analysis). The values obtained from individual and global analysis were statistically different. Spacing lower than 110m, which was found optimal from previous research, did not allow drivers to modify their speeds as the accumulated speed uniformity was quite similar regardless of the average operating speed; and, accumulated speeding was also minimized. Consequently, the scenarios where the TCMs were implemented according to the technical criteria presented a better design quality. On the other hand, age and gender differences did not seem to affect the average speeds or the accumulated speed uniformity and accumulated speeding.

Grass silage making by direct cutting using a Corner Machinery-1300 flail forage harvester

This study presents two-year results on the performance of the Corner Machinery Type 1300 flail forage harvester during the first-cut grass silage making process. The experiment was conducted on a family farm in Western Serbia, on a 3.8 ha plot of sown grassland producing a grass yield of 25.5 to 29.20 t ha-1. The harvester was drawn by a 35 kW Ursus 3512 tractor. Under field operating conditions, at an average operating speed of 2.156 km h-1, the harvester achieved throughput capacity of about 7 t h-1 and a cutting efficiency of 0.176 ha h-1 depending on operating speed, cutting width, yield, plot size and work organisation. The average fuel consumption and energy requirement were 16.02 L ha-1 and 764.154 MJ ha-1, respectively. Due to simultaneous mowing, chopping and loading of the forage material into a trailer, the harvester had a high engine power requirement of 28.69 kW m-1 relative to the cutting width. During the ensiling operation, working time requirement was highest for forage cutting and loading (52.89%), followed by transport of loaded trailers (17.80%) and transport of unloaded trailers (15.87%). The harvester showed satisfactory performance as chop length was mostly below 50 mm on average in about 58.25% of the plant material, this value being in agreement with livestock nutritionists’ recommendations. During silage making from different plants on small family farms, the harvester achieved reliability and satisfactory performance, without coming to standstills due to breakdowns. Key words: Grass silage, forage harvester, performance, operating speed, efficiency, fuel consumption.

Territorial Accessibility Analysis as a Key Variable for Diagnosis of Urban Mobility: A Case Study Manizales (Colombia)

Convenience analysis methodologies are employed in this article in order to assess territorial urban mobility. This paper is based on data collected over a period of time more than a year utilizing GPS devices. More than 18 million readings were collected corresponding to operational characteristics of car, taxi, motorcycle, truck and different modalities of public transport (UPT). The proposed methodology was applied through the mobility plan of the city of Manizales (Colombia) during the year of 2011. Manizales is a medium sized city with approximately 360.000 inhabitants, located in the central range of the Colombian mountains The average operating speed on each street network arc is the primary analysis variable; Geostatistical techniques are applied to predict the average travel time of each transportation mode . The results obtained are shown graphically and correspond to current city mobility data in a manner permitting comparison between transportation modes. It is concluded that the taxi mode of transportation with respect to accessibility provides better accessibility followed in corresponding order by motorcycle, car, truck and finally UPT; it has been determined that UPT provides the worst global accessibility media conditions; however, the UPT is the mode of transport most frequently used by the population (75% of daily trips).

The Analysis of Impacting Urban Expressway Operating Speed Factors

With many large cities accelerating the pace of urban expressway construction, at the same time it has to be thought-provoking which factors is related with the urban expressway operating speed? In this paper, the difference is based on the use of certain urban expressway speed of the computational model and measured to compare the average operating speed of analysis. Then analyzed and listed that may affect urban freeway speed factors, for the future of urban freeway speed computing model to provide some ideas.

The berth allocation problem: Optimizing vessel arrival time

The berth scheduling problem deals with the assignment of vessels to berths in a marine terminal, with the objective to maximize the ocean carriers’ satisfaction (minimize delays) and/or minimize the terminal operator's costs. In the existing literature, two main assumptions are made regarding the status of a vessel: (a) either all vessels to be served are already in the port before the planning period starts, or (b) they are scheduled to arrive after the planning period starts. The latter case assumes an expected time of arrival for each vessel, which is a function of the departure time of the vessel from the previous port, the average operating speed and the distance between the two ports. Recent increases in fuel prices have forced ocean carriers to reduce current operating speeds, while stressing to terminal operators the need to maintain the integrity of their schedule. In addition, several collaborative efforts between industry and government agencies have been proposed, aiming to reduce emissions from marine vessels and port operations. In light of these issues, this article presents a berth-scheduling policy to minimize vessel delayed departures and indirectly reduce fuel consumption and emissions produced by the vessels while in idle mode. Vessel arrival times are considered as a variable and are optimized to accommodate the objectives of the proposed policy while providing ocean carriers with an optimized vessel speed. Example problems using real data show that the proposed policy reduces the amount of emissions produced by vessels at the port in idle mode, optimizes fuel consumption and waiting time at the port by reducing vessel operating speeds to optimal levels and minimizes the effects of late arrivals to the ocean carriers’ schedule.

Consumo de combustível na operação de subsolagem realizada antes e depois de diferentes sistemas de preparo periódico do solo

A subsolagem tem aumentado nos últimos anos de forma indiscriminada, faltando estudos que norteiem os melhores procedimentos para que novos problemas não sejam acrescentados devido a subsolagens inadequadas ou mesmo em solos onde a operação é desnecessária, e principalmente buscar redução no consumo de combustível. Dessa forma, este trabalho teve o objetivo de avaliar o consumo de combustível na operação de subsolagem efetuada antes e depois de diferentes sistemas de preparo periódico do solo, classificado como Nitossolo Vermelho distroférrico. Os preparos foram realizados com arado de discos, arado de discos mais uma gradagem de nivelamento, grade pesada, grade pesada mais gradagem de nivelamento e escarificador. A realização da subsolagem depois dos sistemas de preparo periódico requereu 15% menos de potência na barra de tração. A subsolagem depois dos diferentes sistemas de preparo economizou 16,5% de combustível por área. O deslizamento das rodas motrizes e a velocidade média operacional obtiveram melhor desempenho quando se realizou a subsolagem depois do preparo do solo.

A Variable-Speed Approach for Preventing Cam-Follower Separation

The follower separation is a major impediment to the operating speed increase of force-closed cam mechanisms. This problem traditionally is solved by increasing the spring preload or spring rate to enlarge the return force. An alternative approach with variable cam speed is proposed to prevent follower separation and thereby to raise the average operating speed. By properly designing the cam speed to change the follower motion, the critical motion characteristics leading to follower separation can be avoided. The cam speed trajectory is expressed using the Bezier function. A mathematical model is developed for analyzing the cycle time and the critical times of follower separation. Then a design model for optimizing the critical average cam speed without follower separation is developed to specify the design parameters of this trajectory. Two design examples with different cam motion programs are given for demonstrating the feasibility of this approach.

A Novel Digital Control Technique for Brushless DC Motor Drives

Brushless DC (BLDC) motor drives are continually gaining popularity in motion control applications. Therefore, it is necessary to have a low cost, but effective BLDC motor speed/torque regulator. This paper introduces a novel concept for digital control of trapezoidal BLDC motors. The digital controller was implemented via two different methods, namely conduction-angle control and current-mode control. Motor operation is allowed only at two operating points or states. Alternating between the two operating points results in an average operating point that produces an average operating speed. The controller design equations are derived from Newton's second law. The novel controller is verified via computer simulations and an experimental demonstration is carried out with the rapid prototyping and real-time interface system dSPACE.

Speed Difference and Its Impact on Traffic Safety of One Freeway in China

Although speed differential has long been recognized as a contributing factor to highway crashes, its relationship with crash rate has not been quantitatively established. An analysis of the crash data collected from the Jingjintang Expressway, one of the first freeways to be built in China, reveals a clear association between speed gap and crash rate. A difference in average operating speed between large and small vehicles of 10 to 15 km/h, reflecting a specific traffic composition, is associated with an unusually high crash rate. The speed differential problem is worse in developing countries because of the huge demand for freight transportation. Overloading is a common problem on highways. Heavily loaded trucks cannot reach the minimum freeway speed and so cause other vehicles to change lanes frequently; the situation consequently increases crash risks. Analysis results strongly suggest that managing the speed gap between large and small vehicles would be the most crucial step in combating the highway crash problem.

Development and performance evaluation of okra planter

A three-row ridger planter was developed for planting soaked okra seed on the ridges. The seed metering mechanism in the planter is of inclined plate type. Power is transmitted from ground wheel to metering system through chain and sprokets. The machine has four ridger bottoms with runner type furrow opener for making ridges. The seed is placed in these ridges at desired depth. The ridge size and depth of placement of seed are adjustable. The implement is operated by a 35 hp tractor. During evaluation the field capacity of the machine was found to be 0.2 ha/h with an average operating speed of2.27 kmph. The field efficiency of the planter was found to be 66.5 per cent. There was a saving of 77 man hours per hectare by planting okra seed with planter as compared to making ridges with tractor drawn ridgers followed by manual planting. The cost of operation was found to be Rs. 810/- per hectare and a saving of 76% over manual planting was recorded. The crop parameters and yield were comparable in case of machine planting and manual planting.