Characterization of Drip Emitters and Computing Distribution Uniformity in a Drip Irrigation System at Low Pressure Under Uniform Land Slopes

Characteristics of emitters under low pressure are essential for designing drip irrigation systems. Low pressure data for drip emitters are not available from manufacturers. A laboratory test was conducted to evaluate the performance of five types of newly manufactured drip tapes, especially under a low pressure distribution system. The five drip products that were tested were (i) Toro Drip in PC (PCS 1810-18- 100), (ii) T-Tape (TT15-1245-0100), (iii) Mister_LS (MLD-HDT100), (iv) Mister_PS (MLD-1PC 25), and (v) Netafim (Techline CV 560 050). Drip tapes tested in this study have design discharge rates of 4.00 L/hr @ 206.84 Kpa (1.06 gph @ 30 psi), 1.02 L/hr @ 55.16 Kpa (0.27 gph @ 8 psi), 3.785 L/hr @ 172.37 Kpa (1.00 gph @ 25 psi), 3.785 L/hr @172.37 Kpa (1.00 gph @ 25 psi), and 0.984 L/hr @ 206.84 Kpa (0.26 gph @ 20psi), respectively. All of them, except T-Tape, were pressure compensating (PC) emitters; the T-Tape was non-pressure compensating (NPC). For all products, except Toro, the emitter spacing was 0.305 m (12 inches) and for Toro, it was 0.46 m (18 inches). Mister_PS (MLD-1PC 25) was the point source (PS) emitter and all others were line source emitters. Drip products were tested with 15 different operating pressures ranging from 5.97 KPa (0.87 psi) to 344.74 KPa (50.00 psi). From an evaluation of 60 emitters from each product, the Toro brand showed an average uniformity coefficient (UC) of 91.24 %, with a coefficient of variation (Cv) of 0.06, T-Tape drip products showed an average UC of 96.63 % with a Cv of 0.04, Mister_ LS showed an average UC of 93.12 % with a Cv of 0.08, Mister_PS showed an average UC of 96.33 % with a Cv of 0.04, and Netafim showed an average UC of 97.92 % with a Cv of 0.02. Flow rate vs. pressure head (Q-H) curves were also developed for each drip emitter tested. From emitter exponent values it was observed that all of the pressure compensating (PC) products behaved like NPC emitters at low pressures, although they behaved like PC emitters under normal operating pressures. From statistical analysis, it was determined that except for Netafim product, all other tested products were effective under low operating pressures as were under high operating or recommended pressures. Netafim product had no emission under low pressures. Using the measured average emission rate and developed Q-H curves, the distribution uniformities of all products except Netafim were calculated under low pressure ranges of 5.97 KPa (0.87 psi) to 23.88 KPa (3.50 psi ) for different lengths of laterals and under 0%, 1%, 2

On the Computation Of Part Orientation Using Support Structures in Layered Manufacturing

During the construction of an object by layered manufacturing, it might be necessary to build external supports either to prevent the object from toppling, or to support floating components and overhanging material. The support structures, if necessary, must be built simultaneously with the object, and hence must be accounted for in the path planning of the laser beam or the deposition nozzle. In this paper, we find the best direction offormation of an object by layered manufacturing process that allows the use of support structures. In the orientation determined by the best direction offormation, the object is constructible with a minimal support structure, is stable, and rests on a planar base. Implementation results are also included.Mechanical Engineerin

Project MAXWELL: Towards Rapid Realization of Superior Products

We describe a new methodology for the design and manufacture of mechanical components. The methodology is a synergism of a new, mathematically rigorous procedure for the concurrent design of shape and material composition of components, and a new manufacturing process called MD* for their realization. The concurrent design strategy yields information about the global shape of the component and its material composition. The fabrication of such designs with novel microstructural configurations require unconventional manufacturing processes. MD* is a shape deposition process for the free-form fabrication of parts from single or composite materials and is ideally suited for realizing the aforementioned designs. Project MAXWELL, therefore, promotes the use of layered manufacturing beyond prototyping tasks and offers the possibility of their integration into the mainstream product development and fabrication process..Mechanical Engineerin

Characterization of Drip Emitters and Computing Distribution Uniformity in a Drip Irrigation System at Low Pressure Under Uniform Land Slopes

Characteristics of emitters under low pressure are essential for designing drip irrigation systems. Low pressure data for drip emitters are not available from manufacturers. A laboratory test was conducted to evaluate the performance of five types of newly manufactured drip tapes, especially under a low pressure distribution system. The five drip products that were tested were (i) Toro Drip in PC (PCS 1810-18- 100), (ii) T-Tape (TT15-1245-0100), (iii) Mister_LS (MLD-HDT100), (iv) Mister_PS (MLD-1PC 25), and (v) Netafim (Techline CV 560 050). Drip tapes tested in this study have design discharge rates of 4.00 L/hr @ 206.84 Kpa (1.06 gph @ 30 psi), 1.02 L/hr @ 55.16 Kpa (0.27 gph @ 8 psi), 3.785 L/hr @ 172.37 Kpa (1.00 gph @ 25 psi), 3.785 L/hr @172.37 Kpa (1.00 gph @ 25 psi), and 0.984 L/hr @ 206.84 Kpa (0.26 gph @ 20psi), respectively. All of them, except T-Tape, were pressure compensating (PC) emitters; the T-Tape was non-pressure compensating (NPC). For all products, except Toro, the emitter spacing was 0.305 m (12 inches) and for Toro, it was 0.46 m (18 inches). Mister_PS (MLD-1PC 25) was the point source (PS) emitter and all others were line source emitters. Drip products were tested with 15 different operating pressures ranging from 5.97 KPa (0.87 psi) to 344.74 KPa (50.00 psi). From an evaluation of 60 emitters from each product, the Toro brand showed an average uniformity coefficient (UC) of 91.24 %, with a coefficient of variation (Cv) of 0.06, T-Tape drip products showed an average UC of 96.63 % with a Cv of 0.04, Mister_ LS showed an average UC of 93.12 % with a Cv of 0.08, Mister_PS showed an average UC of 96.33 % with a Cv of 0.04, and Netafim showed an average UC of 97.92 % with a Cv of 0.02. Flow rate vs. pressure head (Q-H) curves were also developed for each drip emitter tested. From emitter exponent values it was observed that all of the pressure compensating (PC) products behaved like NPC emitters at low pressures, although they behaved like PC emitters under normal operating pressures. From statistical analysis, it was determined that except for Netafim product, all other tested products were effective under low operating pressures as were under high operating or recommended pressures. Netafim product had no emission under low pressures. Using the measured average emission rate and developed Q-H curves, the distribution uniformities of all products except Netafim were calculated under low pressure ranges of 5.97 KPa (0.87 psi) to 23.88 KPa (3.50 psi ) for different lengths of laterals and under 0%, 1%, 2

An Integrated Software System for Process Planning for Layered Manufacturing

An integrated process planning system for layered manufacturing (LM) reduces the time between design and part fabrication and improves the quality of the final part. Process planning for most LM processes includes part orientation, support structure generation, slicing, and path planning. In this paper we describe an integrated process planning system we are developing. Our software accommodates both novel and traditional design models as input, and supports a variety of LM processes. The modules described in this paper include Solid Builder Module, which generates a solid model from design data such as medical images, surface functions, or digital elevation models; Orientation Module, which determines the optimal build orientation of a part and automatically generates the support structures required; and Adaptive Slicing Module, which adaptively slices the part.Mechanical Engineerin

Variation of hemodynamic response following induction and tracheal intubation: etomidate vs midazolam

Background: Induction and endotracheal intubation are invariably associated with certain cardiovascular changes during anaesthesia practice and can lead to sudden swings of blood pressure, arrhythmias, MI and cardiovascular collapse especially in geriatric and haemodynamically unstable patients. Therefore it is desirable to use a safer agent with fewer adverse effects to minimise these complications. Present prospective randomized study is designed to compare the haemodynamic alterations and various adverse effects following induction with etomidate and midazolam.Methods: Hundred ASA I and II patients of age group 18-60 years scheduled for elective surgical procedure under general anesthesia were randomly divided into two groups of 50 each receiving etomidate (0.3mg/kg) and midazolam (0.15mgk/kg) as an induction agent. Vital parameters before and after induction and thereafter at specified time interval following laryngoscopy and intubation were recorded for comparison. Adverse effect viz. pain on injection, apnea and myoclonic activity were also carefully watched.Results: Demographic variables in both the groups were comparable. Patients in both the groups showed little change in mean arterial pressure (MAP) and heart rate (HR) from baseline value (p >0.05). Pain on injection and myoclonic activity were seen in etomidate group while delayed awakening was seen with Midazolam group.Conclusions: This study concludes that both etomidate and midazolam provides haemodynamic stability but Midazolam can be preferred as an induction agent in view of fewer side effects

Attenuation of stress response to laryngoscopy and intubation: sublingual nitroglycerin spray vs intravenous fentanyl and sublingual nitroglycerin spray

Background: Laryngoscopy and tracheal intubation is invariably associated with certain cardiovascular changes such as tachycardia, rise in blood pressure and a wide variety of cardiac arrhythmias. 1 Such complications are highly detrimental in patients with limited cardiovascular reserve specially in geriatric and elderly population. Various pharmacological agents have been used to attenuate these stress responses but none has yet been considered ideal. Therefore, purpose of this study is to investigate the efficacy of sublingual Nitroglycerine spray alone and sublingual Nitroglycerine spray with intravenous Fentanyl to attenuate the pressor response to laryngoscopy and intubation in normotensive patients.Methods: A total of 120 ASA I and II patients of age group 18-60 years scheduled for elective surgical procedure under general anesthesia were randomly divided into 3 groups of 40 in each group. Group 1 control group, Group 2, received NTG sub-lingual spray (0.4mg/spray) two min. before induction, and Group 3 received inj. Fentanyl (2µg/kg) 5min before + NTG sub-lingual spray (0.4 mg/spray) 2min before induction. Vital parameters before and after induction and thereafter at specified time interval following laryngoscopy and intubation were recorded for comparison.Results: Demographic characteristics and baseline vital parameters in both the groups were comparable. Significant differences in mean arterial pressure (MAP) and heart rate (HR) were observed in between the groups during postintubation period.Conclusions: Combination of intravenous Fentanyl plus Nitroglycerin spray is more effective than NTG alone in attenuating the stress response following laryngoscopy and intubation

The New Mechanical Engineering Curriculum at the University of Michigan

This paper describes the new undergraduate program in the Department of Mechanical Engineering and Applied Mechanics at the University of Michigan, Ann Arbor. The restructuring of the program was initiated by a comprehensive review in 1992 that included surveys of alumni, students, and industrial representatives, as well as faculty assessment of current trends and future needs. The program is intended to address the changing backgrounds of incoming students, to prepare the students for new and diverse challenges in the workplace, and to provide a structure for the curriculum to evolve with changing technology. The new curriculum consists of three integrated courses in Design and Manufacturing, two Laboratory courses, and several redesigned courses in the Engineering Sciences. The redesigned program provides students with extensive hands‐on experience, a comprehensive experience in teamwork and technical communication, and the opportunity to exercise and develop their creativity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94791/1/j.2168-9830.2001.tb00624.x.pd

How many locations do we need per day to reliably describe the habitat use of translocated rhinos in Manas NP?

The Indian Rhino Vision (IRV) 2020 program was designed in 2005 in Assam for maintaining existing rhino populations and to re-introduce rhinos in the earlier distribution ranges of Assam. The programme was launched on 12th April 2008. The government of Assam with donor support translocated two male rhinos from the Pobitora WLS to the Buraburijhar area under Basbari range in Manas National Park. As a follow up to these translocations to understand the adaptation of the rhinos, it was important to assess the monitoring frequencies, habitat use and distribution pattern of rhinos in the new habitat. Monitoring was primarily based on radio-telemetry techniques and direct observation. The monitoring team maintains a vigil on the released rhinos all round the day and the observations were systematically recorded three times a day. During this exercise it was found that the rhinos prefer to use grasslands, swamps and marshy areas (beels and rivulet). Key Words: Indian Rhino Vision (IRV) 2020, Radio-Telemetry, Translocatio