Factors that affect the efficiency

Surface finish of internal surfaces - Kffieicney inerea,ses from better surface finishes are mostly attributable to the specific speed Ns (discussed in Chapter 6) of the pump. Generally, the improvements in surface finishes are economically justifiable in pumps with low specific speeds. 

Wear ring tolerance - Close tolerances on the wear rings have a tremendous effect on the pump s efficiency, particularly for pumps with a low specific speed (Ns 1500). 

Mechanical losses - Bearings, lip seals, mechanical seals, packings, etc., all consume energy and reduce the pump s efficiency. Small pumps (less than 15 HP) are particularly susceptible. 

Impeller diameter - There will be an efficiency reduction with a reduction in the impeller diameter. For this reason, it s not recommended to reduce (trim) the impeller by more than 20%. For example, if a pump takes a fiill sized 10-ineh impeller, don t trim the impeller to less than 8-inches diameter. This would be a 20% reduction. 

scosity - Viscous liquids generally have a prejudicial effect on efficiency. As the viscosity of the fluid goes up, generally the effieiency of most pumps goes down. There are exceptions. 

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The C02-fixing pathways used by a specific biomass species will affect the efficiency of photosynthesis, so from a biomass energy standpoint, it is desirable to choose species that exhibit high photosynthesis rates to maximize the yields of biomass in the shortest possible time. Obviously, however, there are numerous factors that affect the efficiency of photosynthesis other than the... 

In gas-filled as well as scintillation detectors, the observed count rate is typically less than the actual decay rate of the radionuclide. The efficiency of detection may differ from particle to particle under identical conditions using the same type of detector. The factors that affect the efficiency of detection are operating voltage, resolving time, geometry of the instrument used in relation to the position of the sample with respect to the detector, scaler, energy resolution, absorption by cells, and sometimes constituents of the sample itself. 

In contrast to what is usually observed in organic photochemistry, exothermic energy transfer involving transition metal complexes does not always occur at diffusion controlled rates (204). Several investigations employing well-characterized aromatic triplet donors and organometallic acceptors have been aimed at elucidating the factors that affect the efficiencies... 

Ball mills reduce the size of particles through a combined process of impact and attrition. Usually they consist of a hollow cylinder that contain balls of various sizes, which is rotated to initiate the grinding process. There are a number of factors that affect the efficiency of the... 

There are several primary factors that affect the efficiency of separation through CE the buffer system, the pH of the electrophoresis electrolyte, the voltages applied (higher voltages improve separation), and the interface between CE and ICP-MS, which reduces the ratio of forced flow to electro-osmotic flow. The relative standard deviation values (RSD < 9%) obtained through the ICP-MS technique confirm the suitability for arsenic speciation in saline waters. In terms of reliability, one can say that the ICP-MS method is more reliable than HG-AAS for arsenic speciation in water. 

Factors That Affect the Efficiency of the Biological Pump... 

An efficient biological pump means that a large fraction of the system s net production is removed from the surface waters via export mechanisms. Factors that affect the efficiency of the biological pump are numerous and include nutrient supply and plankton community structure. 

Ammonium fixation is also a factor that affects the efficiency of nitrogen utilization (see Chapter 11). If the soil is high in 2 1 type minerals much of the ammonium will be fixed and thereafter be nitrified or released to crops only slowly. Under some conditions this may be an advantage, but present information indicates that it is more likely to be a... 

Although electrospray is a relatively simple teehnique from an instrumentation stand point, the mechanism involved in the ionization and the factors that affect the efficiency of a compound is not straightforward (Cole, 1997). There... 

Hot alkali is used to dissolve the pectic substances that bind the ultimate fibres into bundles. Some commercial processes, for reasons of cheapness, use sodium hydroxide almost exclusively as the alkali, though it is used sometimes in admixture with sodium carbonate. The main factors that affect the efficiency and economics of chemical degumming are ... 

Factors that affect the rate-determining step (171 172) will influence the overall rate of reaction. A stronger nucleophile, such as hydrazine, is certainly more efficient than hydroxide, but no studies have been reported on the alternative variation of the electrophilicity of the 4-carbonyl group. Ring-opening may occur at either the 3 4.35,91,136,136 qj. 1 2-bouds in pyridopyrimidine-2,4(lH,-... 

A review of chitosan microspheres as carrier for drugs pubUshed recently by Sinha et al. provides insight into the exploitation of the various properties of chitosan to microencapsulate drugs. Various techniques used for preparing chitosan microspheres and evaluation protocols have also been reviewed, together with the factors that affect the entrapment efficiency and release ki-nefics of drugs [194]. 

In order to provide further insight into the post-combustion ratio and the heat transfer efficiency, the factors that affect the PCR and HTE will be delineated. The factors that affect the PCR and HTE will be discussed separately with the understanding that a complex relationship may exist between the two parameters. The factors that affect the PCR are shown in Table 4, and Fig. 3 demonstrates the primary conditions for postcombustion. The PCR should be kept relatively high, since the fuel consumption decreases with an increase in the PCR at the same HTE (Aukrust, 1993). However, as mentioned, high PCR may lead to problems due to increases in ... 

A nnmber of factors can affect the efficiency of SO rednction additives in the FCCU. Some of these factors are related to the operation of the FCCU, and some are directly related to the composition of the SO additive itself. The following are significant factors that affect additive performance ... 

This experimental design technique is widely used as a tool to verify the efficiency of several processes. In the present work, it was used for the purpose of obtaining information from the EPS production process consequently, a reduction in the variability, as well as in operational costs can be expected. The choice of the variables (factors that affect the process), as well as the superior (+), lower (-), and central (0) levels used in the design, was defined from preliminary studies that defined the parameters as the most significant for the production of EPS. The selected variables were aeration, agitation, and initial substrate concentration (see Table 1). 

Prior to discussing scaleup, the factors that affect tray efficiency need to be addressed. These factors are addressed in Secs. 7.3.1 to 7.3.3. Considerations relevant to the effect of flow regime were previously discussed in Secs. 6.4.4 and 6.4.5. 

Temperature is a very important factor that affects extraction efficiency, regardless of the applied technique. During MAE carried out in a closed vessel the... 

The main factors that affect the separation efficiency and yield in the membrane separation of beer are beer composition, membrane characteristics, process parameters, and membrane fouling. 

Apart from the inherent efficiency of the reactions leading to the light-induced formation of a ROS as summarized by the relevant apparent quantum yield and action spectrum, the observed rate of production will depend on other factors that affect the photon exposure including water column composition and depth (Chapter 3), time of day (i.e., solar zenith angle), season, latitude (Chapter 2), and physical transport processes (Chapter 4). For more details regarding the fundamental equations used to define the rates of primary and secondary photochemical reactions and their application to aquatic systems, the reader is referred to recent reviews on this topic [41,42]. 

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