Investigation Of Different Parameters Research Articles

Changes in Visual Parameters during Paramenstruum in a Rural Population of Eastern India: A Pilot Study

Aim This study aims to analyze a set of symptoms of visual difficulties due to accommodative changes before and during the period of menstruation.  Methods This cross-sectional study includes 60 females of the rural population having an accommodative facility of 14 cycles/min with ±2.00D flippers. All subjects have undergone a comprehensive ocular examination which also includes investigation of different parameters of accommodation and convergence before and during menstruation. This Statistical analysis was done with the help of paired T test and the result was shown as significant if P< 0.05.  Results Pre-menstruation no accommodative changes were found. During menstruation, all the subjects were found with a significant change in NPA (OD, OS), AA (OD, OS), NRA, PRA, PFV (Break-Near) and AF (OU) during menstruation. 66.7% of subjects were found with symptoms of headache, backache, difficulty in reading and blurring of vision during menstruation. After prolong near work 16.7% of subjects were found with the blurring of near vision 16.7% were found with the blurring of distance vision.  Conclusion Accommodative insufficiency along with its associated symptoms may induce during the menstruation cycle. The clinician should consider accommodative changes during eye examination of an adult female.

Extraction and preconcentration of lead (II) in various water and food samples by orbital shaker-assisted magnetic solid phase extraction method using a new magnetic poly linoleic acid-polystyrene-PDMS block copolymer

The aim of this study was to develop a practical orbital shaker-assisted magnetic solid phase extraction (OSA-MSPE) method for the determination of lead by FAAS. A new magnetic poly linoleic acid-polystyrene-polydimethylsiloxane (PSt-PLina-PDMS) hydrophobic graft copolymer was synthesized and characterized by NMR, FT-IR, SEM-EDX, DSC, TGA, BET and used as adsorbent for the extraction of Pb (II). This adsorbent can be used at least 50 times without any decrease of its adsorption properties for the adsorption and elution of analyte ions. Several analytical parameters including pH, adsorbent amount, sample volume, shaking time, etc. were optimized. Multivariate optimization was used for the investigation of different parameters. The linear range at optimum operating condition was 1.7–84 μg L−1. The limit of detection (LOD) and limit of quantification (LOQ) were 0.5 μg L−1, 1.7 μg L−1, respectively. Intraday and interday relative standard deviation (RSD %), enhancement factor (EF) and adsorbent capacity were found as 1.9%, 3.3%, 166.7, 50 mg g−1, respectively. OSA-MSPE method was tested with certified reference materials including LGC-6010 (Hard Drinking Water), NCS ZC73032 Celery and CS-M-3 Control Sample Microelements in Mushroom Powder for the accuracy. Experimental results for lead were confirmed with certified values. Present method was successfully applied to various liquid and solid food samples. The OSA-MSPE method has some important features such as selective, sensitive, low LOD, LOQ and RSD, pre-concentration factor (PF) and high enhancement factor (EF). High tolerance limits against matrix ions were achieved.

The ABC of happiness: Validation of the tridimensional model of subjective well-being (affect, cognition, and behavior) using Bifactor Polytomous Multidimensional Item Response Theory

BackgroundHappiness is often conceptualized as subjective well-being, which comprises people's evaluations of emotional experiences (i.e., the affective dimension: positive and negative feelings and emotions) and judgements of a self-imposed ideal (i.e., the cognitive dimension: life satisfaction). Recent research has established these two dimensions as primary parts of a higher order factor. However, theoretical, conceptual, and empirical work suggest that people's evaluations of harmony in their life (i.e., the sense of balance and capacity to behave and adapt with both acceptance and flexibility to inter- and intrapersonal circumstances) constitutes a third dimension (i.e., the behavioral dimension). This tridemensional conceptualization of subjective well-being has recently been verified using Unidimensional Item Response Theory (UIRT) and Classical Test Theory (CTT). Here, we use a recently developed and more robust approach that combines these two methods (i.e., Multidimensional Item Response Theory, MIRT) to simultaneously address the complex interactions and multidimensionality behind how people feel, think, and behave in relation to happiness in their life. MethodA total of 435 participants (197 males and 238 females) with an age mean of 44.84 (sd = 13.36) responded to the Positive Affect Negative Affect Schedule (10 positive affect items, 10 negative affect items), the Satisfaction with Life Scale (five items), and the Harmony in life Scale (five items). We used Bifactor-Graded Response MIRT for the main analyses. ResultAt the general level, each of the 30 items had a strong capacity to discriminate between respondents across all three dimensions of subjective well-being. The investigation of different parameters (e.g., marginal slopes, ECV, IECV) strongly reflected the multidimensionality of subjective well-being at the item, the scale, and the model level. Indeed, subjective well-being could explain 64 % of the common variance in the whole model. Moreover, most of the items measuring positive affect (8/10) and life satisfaction (4/5) and all the items measuring harmony in life (5/5) accounted for a larger amount of variance of subjective well-being compared to that of their respective individual dimensions. The negative affect items, however, measured its own individual concept to a lager extent rather than subjective well-being. Thus, suggesting that the experience of negative affect is a more independent dimension within the whole subjective well-being model. We also found that specific items (e.g., “Alert”, “Distressed”, “Irritable”, “I am satisfied with my life”) were the recurrent exceptions in our results. Last but not the least, experiencing high levels in one dimension seems to compensate for low levels in the others and vice versa. ConclusionAs expected, the three subjective well-being dimensions do not work separately. Interestingly, the order and magnitude of the effect by each dimension on subjective well-being mirror how people define happiness in their life: first as harmony, second as satisfaction, third as positive emotions, and fourth, albeit to a much lesser degree, as negative emotions. Ergo, we argue that subjective well-being functions as a complex biopsychosocial adaptive system mirroring our attitude towards life in these three dimensions (A: affective dimension; B: behavioral dimension; C: cognitive dimension). Ergo, researchers and practitioners need to take in to account all three to fully understand, measure, and promote people's experience of the happy life. Moreover, our results also suggest that negative affect, especially regarding high activation unpleasant emotions, need considerable changes and further analyses if it is going to be included as a construct within the affective dimension of a general subjective well-being factor.

Mathematical investigation of different parameters of the passive desiccant wheel

A passive desiccant wheel is a rotating dehumidifier that can be regenerated using the room’s return (exhaust) air and does not require hot air for regeneration as in the active desiccant wheel. In this study, a one-dimensional mathematical model has been developed to analyze the parameters of the passive wheel and to compare this with the existing active desiccant wheel. To transform the active desiccant wheel into the passive desiccant wheel, silica gel B has been utilized as the desiccant material since it operates better in a saturated air environment. Additionally, a cooling coil has been placed in front of the wheel to provide saturated and cold air. Therefore, regeneration has been accomplished without the usage of external heat due to the relative humidity difference between the return air and the saturated air. From the mathematical results of this study, it has been found that the optimal ratio of process area to regeneration area and rotational speed of the passive desiccant wheel are 0.44 (i.e., regeneration area is equal to the 69% of total wheel cross section) and 7–15 rph, respectively. Similarly, the optimum regeneration and process velocity of the passive desiccant wheel was found to be 2 m/s. Further, the exit temperature of the process air of the passive wheel is less than the active wheel in all cases because the return air of the room has been used for reactivation, which is the fundamental advantage of a passive wheel over an active wheel and is suitable to supply in the room.

A Study on Parameters Influencing Blast-Induced Frequency Content and Dominant Frequency Attenuation

Adverse effects of the blasting vibration on surrounding structures intensify importance of investigation on the blast frequency content while it has not been fully considered in blasting design. In this study, blast-induced frequency content and dominant frequency attenuation are investigated. The results of this study and its comparison with the previous studies demonstrate that investigation of different parameters influencing blast-induced frequency content including peak blast load pressure, rise time, and falling time by the experimental pressure-time history with its Fast Fourier Transform (FFT) analysis leads to the similar results of study by the velocity-time recorded data of an infield blasting. The outcomes of this study on dominant frequency attenuation for different types of explosives but in the same material show approximately the same dominant vibration frequency in far-field for different explosives, whereas a rapid drop of dominant frequency to half of the initial value in near distance to the blasthole can be observed. Investigation on dominant frequency attenuation versus distance for the materials with different natural ground frequencies demonstrates that the geomaterial tends to pass the vibration frequency closer to its natural frequency. If the earth has a lower natural frequency, it will pass the waves with lower dominant frequencies, but it will attenuate the waves with higher dominant frequency.

Investigation of different parameters of cube printed using PLA by FDM 3D printer

Additive manufacturing creates objects by deposition of material layer by layer. Due to its versatility and low cost, the most widely used additive manufacturing technique is FDM. Fused Deposition Modeling makes use of a thermoplastic filament that is melted and extruded through a heated extrusion nozzle. The properties of FDM-produced parts are varied by the processing parameter that includes infill density, layer thickness, infill pattern, print speed. Fused Deposition Modelling (FDM) technology allows users to control the density of models through infill. In this research work, a cube was modeled on Solidworks software, slicing of cube model was done using Ultimaker Cura software. PLA material with infill pattern of Grid and Tri-Hexagon and infill density of 20%, 40%, and 60% was used for printing the model on Ultimaker 2 + FDM printer. This research focuses on the influence of infill density and infill pattern in 3D printed cubes made of polylactic acid (PLA) by examining their printing time and dimensional accuracy.

Assessment of breast cancer primary tumor material in a 3D in vivo model.

Breast cancer is the most common malignant tumor in women and highly heterogeneous with a variety of different molecular subtypes. The analysis of the individual tumor biology is necessary to develop a specific and individualized treatment plan for every patient. The chick chorioallantoic membrane (CAM) model, a 3D-in-vivo-tumor-model, could potentially provide a methodology that facilitates the gain of additional information regarding the tumor biology as well as the testing of the tumor's individual sensitivity to different therapies. The objective was to establish the grafting of different breast cancer primaries onto the CAM for tumor profiling and the investigation of different parameters. Breast cancer primary tissue of different patients was grafted onto the CAM. Subsequently, 3D volume and perfusion measurements were performed during the engraftment period. Histological analyses of the tumors were carried out after the engraftment period. The grafting of the breast cancer primaries onto the CAM was successful. The tumors remained partially vital and displayed angiogenic development on the CAM. Breast cancer primary material can be grafted onto the CAM and we observed visible and measurable changes of perfusion over time.

Macroparticle-enhanced cultivation of Lentzea aerocolonigenes: Variation of mechanical stress and combination with lecithin supplementation for a significantly increased rebeccamycin production.

The actinomycete Lentzea aerocolonigenes produces the antitumor antibiotic rebeccamycin. In previous studies the rebeccamycin production was significantly increased by the addition of glass beads during cultivation in different diameters between 0.5 and 2 mm and the induced mechanical stress by the glass beads was proposed to be responsible for the increased production. Thus, this study was conducted to be a systematic investigation of different parameters for macroparticle addition, such as bead diameter, concentration, and density (glass and ceramic) as well as shaking frequency, for a better understanding of the particle-induced stress on L. aerocolonigenes. The induced stress for optimal rebeccamycin production can be estimated by a combination of stress energy and stress frequency. In addition, the macroparticle-enhanced cultivation of L. aerocolonigenes was combined with soy lecithin addition to further increase the rebeccamycin concentration. With 100 g L-1 glass beads in a diameter of 969 µm and 5 g L-1 soy lecithin a concentration of 388 mg L-1 rebeccamycin was reached after 10 days of cultivation, which corresponds to the highest rebeccamycin concentrations achieved in shake flask cultivations of L. aerocolonigenes stated in literature so far.

An investigation of different parameters on the penetration depth and welding width of Ti-6Al-4V alloy by plasma arc welding

In this paper, the effect of plasma arc welding (PAW) process parameters on the mechanical properties and macro- and microstructure of Ti-6Al-4V alloy is discussed. These parameters including welding current, welding speed, and plasma gas orifice diameter have an effect on the weld bead depth and width. Macrograph results indicate that there is a certain range of welding electric current and welding speed in which full-penetration weld is obtained and weld beads are free from defect. Experimental results show that the specimen mechanical strength is favorable and comparable to those of the base material, but the sample elongation is low entirely. Moreover, the results indicate that using an optimum range of welding speed and current, which lead to decreased heat input, makes greater mechanical strength and better relative ductility. The fusion zone microstructure consists of martensite (α′), massive α (αm), acicular α, and retained β phase.

An efficient and comparative adsorption of Congo red and Trypan blue dyes on MgO nanoparticles: Kinetics, thermodynamics and isotherm studies

Cubic phase of MgO nanoparticles were prepared by microwave-assisted combustion synthesis and investigated for the removal of toxic dyes like Congo Red (CR) and Trypan blue (TB). The crystallite size of the MgO nanoparticle was calculated to be 18 nm from XRD pattern. The sample was further characterized by FTIR, TGA and FESEM techniques. The dyes were subjected to prototypical batch adsorption process, including investigation of different parameters like MgO dosage, dye concentration, solution pH, agitation speed and temperature. It was found that, 0.2 g of MgO NPs showed maximum removal efficiency for both the dyes (more than 98%), having 25 ppm of dye concentration at an acidic pH (3–4). The maximum loading capacity of MgO NPs was obtained to be 136 mg/g and 132 mg/g for CR and TB, respectively. Different thermodynamic parameters like ΔG0, ΔH0 and ΔS0 were measured. The negative ΔH0 and the positive ΔS0 values for both the dyes correspond to an exothermic process and an increase in randomness of the adsorbent and dye. The isotherm analysis exhibited that the Freundlich model fits better to the experimental equilibrium data, suggesting heterogeneous surface of the nanoparticles. Whereas, the kinetic data revealed a pseudo 2nd order rate for adsorption process.

Metal foaming by powder metallurgy process: investigation of different parameters on the foaming efficiency

Aluminium foams, produced by powder metallurgy process, have significant potential applications for uses in weight-sensitive structural parts. Problems in the production of metal foams arise from the lack of knowledge in the control of process parameters. The results are frequently uneven and un­predictable variations in the structure and properties of the final foamed parts are observed. This paper aims to investigate the effect of different para­meters of the powder metallurgy with foaming agents process on the foaming efficiency. The parameters examined included the powder morpho­logy, the compaction pressure and the foaming temperature. During the foaming stage, for each set of parameters the porosity-time (Pf-t) diagrams were created and the foaming efficiency was calculated (η=Pfmax). Results indicated that the highest foaming efficiency was observed at the specimens with the fine alu­min­ium powder, with high (700 MPa) compaction pressure and high foaming temperatures (800 oC). Finally, compression tests were per­formed on the foamed specimens with the higher foaming efficiency in order to investigate their s-e response. Furthermore, average compressive strength and density were estimated and presented.

A statistical investigation of different parameters influencing compressive strength of fly ash induced geopolymer concrete

This paper statistically investigates the influence of parameter, namely curing temperature, molarity, NaOH/Na2SiO3, and activator‐to‐fly ash ratio on the compressive strength of low calcium fly ash‐based geopolymer concrete. This paper also investigates the effect of delay time prior to curing on the compressive strength of geopolymer concrete. The results of the experimental investigation show that these parameters notably influence the development of the mechanical strength of the final product. The statistical investigation shows that the early compressive strength is significantly affected by the synergistic effect of a linear term of curing temperature, molarity, and activator‐to‐fly ash ratio while NaOH/Na2SiO3 ratio was found to be not so statistically significant. The numerical algorithm formulated using regression analyses were simultaneously optimized by utilizing response optimizer method. A constitutive model which represents a relationship between the compressive strength and splitting tensile strength is also proposed.

Preparation of Saussurea costus Traditional Oil and Investigation of Different Parameters for Standardization

Background and objective: Medicinal oils are one of the most common and special dosage forms in oral and topical therapies of Persian medicine (PM). The oil of Saussurea costus (bitter qust) root is prominent topical oil with different applications in PM. In this study, the oil of bitter qust was prepared according to ancient Persian medical texts. Methods: To prepare traditional qust oil, 100 g of the root was soaked in 600 mL aqueous ethanol 25% overnight. The supernatant was then filtered and boiled in 800 g sesame oil until all water was evaporated. The essential oil of the root and volatile components of its traditional oil were extracted using hydro-distillation method in a Clevenger-type apparatus and were analyzed by gas chromatography-mass spectrometry (GC-MS) method. Total phenolics, flavonoids, tannins and polysaccharides were determined by spectrophotometric methods to evaluate the chemical parameters of traditional bitter qust oil. Results: The content of volatile compounds in both investigated samples was determined (0.5% and 0.1% (v/w), respectively). Dehydrocostus lactone and 1, 3-cyclooctadiene were two similar main compounds in the both analyzed samples. Total phenolics (788.290±0.61 mg/L gallic acid equivalent (GAE)), flavonoids (303.2±2.52 mg/L catechin equivalent (CE)), tannins (23.97±0.52 mg/L GAE) and polysaccharides (9.240±0.13 mg/L dextrose equivalent (DE)) contents were determined. Conclusion: According to the obtained data, dehydrocostus lactone could be used for determination and evaluation of traditional bitter qust oil.

Iron Oxide NPs Facilitated a Smart Building Composite for Heavy-Metal Removal and Dye Degradation.

Due to the growing population, drought, and the contamination of conventional water sources, the need for clean water is rising worldwide with high demand. The application of nanomaterials for water purification can provide a better water quality, by eliminating toxic metals and also decomposing organic contaminants. Exploitation of industrial coal-burned byproduct, fly ash, through nanomodification has been developed in this exertion for the treatment of wastewater along with heavy-metal remediation and dye degradation. The fly ash was sintered at 1000 °C with addition of hydrothermally synthesized iron oxide nanoparticles to make a cementitious composite (FA10C) using an alkali activator (NaOH + Na2SiO3) at ambient temperature. Chemical investigations of the fly ash and the FA10C composites were done by X-ray fluorescence techniques. Analysis of FA10C by X-ray diffraction, Fourier transform infrared, field emission scanning electron microscopy, energy-dispersive spectrometry, and dynamic thermal analysis/thermogravimetric techniques revealed that nanodimensioned rod-shaped mullite formation and its interlocking textures enhance the strength of the building composite. Furthermore, the cementitious composite (FA10C) has been used as an adsorbent to remove heavy metals (lead, chromium, cadmium, copper) and carcinogenic dyes (methylene blue, Congo red, and acid red-1) from their aqueous solutions. The mineralogical features of the composite FA10C and its adsorption capacities/efficiencies were studied by systematic investigation of different parameters, and the adsorption data have been analyzed using Langmuir isotherm. The experimental findings suggest that the iron oxide nanoparticles facilitated fly ash can be implemented as a substitute cementitious composite (greenhouse effect) in construction technology being an energy-saving, low cost, and eco-friendly process in adsorbent manufacturing.

Experimental investigation of different parameters at a combined cross wedge rolling and multi-directional forging process

To forge a flashless crankshaft within few steps and with low energy consumption innovative forging processes are necessary, such as cross wedge rolling and multi-directional forging. The direct combination of the two forming processes normally leads to flash at the bottom of the crankweb preform after the multi-directional forging. The reason for the flash generation is the rotation-symmetric cross wedge rolled billet, which is formed laterally to the main axis during multi-directional forging. In this paper, a parameter field in which flashless crankshaft preforms can be forged is presented. The parameters varied within the experimental research are the forming angle and the cross section area reduction at cross wedge rolling as well as the axis offset, the billet temperature and the forming velocity at the multi-directional forging. The limits of this flashless parameter field are shown in several diagrams. For a flashless combination of two forming process low values for all parameters such as a forming angle α = 30°, a cross section area reduction ΔA = 30%, and a billet temperature T = 1050 °C are recommended. Furthermore, the intensity of the influence of the significant parameters are shown. The cross section area reduction ΔA thereby caused the highest range at flash generation with 0.4 mm.

Determination of doping peptides via solid-phase microelution and accurate-mass quadrupole time-of-flight LC-MS.

A complete analytical protocol for the determination of 25 doping-related peptidic drugs and 3 metabolites in urine was developed by means of accurate-mass quadrupole time-of-flight (Q-TOF) LC-MS analysis following solid-phase extraction (SPE) on microplates and conventional SPE pre-treatment for initial testing and confirmation, respectively. These substances included growth hormone releasing factors, gonadotropin releasing factors and anti-diuretic hormones, with molecular weights ranging from 540 to 1320Da. Optimal experimental conditions were stablished after investigation of different parameters concerning sample preparation and instrumental analysis. Weak cation exchange SPE followed by C18 HPLC chromatography and accurate mass detection provided the required sensitivity and selectivity for all the target peptides under study. 2mg SPE on 96-well microplates can be used in combination with full scan MS detection for the initial testing, thus providing a fast, cost-effective and high-throughput protocol for the processing of a large batch of samples simultaneously. On the other hand, extraction on 30mg SPE cartridges and subsequent target MS/MS determination was the protocol of choice for confirmatory purposes. The methodology was validated in terms of selectivity, recovery, matrix effect, precision, sensitivity (limit of detection, LOD), cross contamination, carryover, robustness and stability. Recoveries ranged from 6 to 70% (microplates) and 17-95% (cartridges), with LODs from 0.1 to 1ng/mL. The suitability of the method was assessed by analyzing different spiked or excreted urines containing some of the target substances.

Engineering biodegradable micelles of polyethylenimine-based amphiphilic block copolymers for efficient DNA and siRNA delivery

Polycationic micelles have shown advantageous properties as nucleic acid delivery vectors both in vitro and in vivo. In contrast to polycationic micelles reported so far, we designed particles integrating a sufficient nucleic acid condensation capability by polycationic polyethylenimine (PEI) segments as well as only a mild cytotoxic behavior. The micelles composed of a hydrophobic oligoester core with glycolide units resulting in fast degradation after cellular internalization in combination with PEG moieties acting as shielding agents. By grafting branched 25kDa polyethylenimine (PEI25) and poly(ethylene glycol) (PEG) on poly[(ε-caprolactone)-co-glycolide] (CG), amphiphilic PEI-CG-PEI and PEG-CG block copolymers were used to form a series of micelles via self-assembly of PEI-CG-PEI or co-assembly of both copolymers for DNA and siRNA delivery. This modular system enabled a systematic investigation of different parameters and their synergetic effects as different functions were introduced. The polyplex formation and serum stability, cytotoxicity, and transfection activity could be tailored by changing the CG chain length in PEI-based copolymer, incorporating PEG-CG, and varying the N/P ratio. All micelle-based polyplex compositions showed high DNA transfection activity according to reporter gene-expression and an exceptionally high knockdown in siRNA delivery experiments. Remarkably, the GFP expression of >99% cells was successfully knocked down by micelle-mediated siRNA interference, resulting in a decrease of two orders of magnitude in fluorescence intensity. Incorporation of PEG-CG in the micelles reduced the PEI-related cytotoxicity, and markedly enhanced the serum stability of both DNA and siRNA polyplexes. Compared with homo-PEI25, these micelles showed several advantages including the lower toxicity, higher siRNA transfection efficiency and higher polyplex stability in the presence of serum. This study therefore provides an effective approach to tune the structure, property and function of polycationic micelles for efficient DNA and siRNA delivery, which could contribute to the design and development of novel non-viral transfection vectors with superb functionality.

Investigation of Different Parameters of Dynamic Source Routing for Wireless Sensor Networks for varying terrain areas and different speed (node speed)

The purpose of this experimental study is to measure the ability of the routing protocol to react to the network topology change while continuing to successfully deliver data packets to their destinations. To measure this ability, different scenarios are generated by varying the maximum speed in the network that also over different terrain areas. The main focus of this paper is to discuss and evaluate the performance of different parameters in different scenarios and different terrain areas which may be small, large and very large in wireless sensor network using Dynamic Source routing protocols and for monitoring of critical conditions with the help of important parameters like Packet Delivery Fraction, End-to-End Delay, Average Throughput, NRL and Packet loss% in different scenarios [1]. This paper describes the performance matrices on different topologies based on varying the maximum speed and keeping the constant pause time in different terrain areas which is small, large and very large. Simulations are run by considering DSR routing protocol. In order to get realistic performance, the results are averaged for a number of scenarios. Investigators were not attempting to measure the protocol performance on a particular workload taken from real life, but rather to measure the protocol, performance under different range of conditions [1]. Investigators use network simulator ns-2 to simulate wireless networks with various wireless routing protocols. NS-2 is a packet- level, discrete event simulator, widely adopted in the network research community. Keywords- Average End-to-End Delay, Average Throughput, Network Simulator, Packet Delivery Fraction, Wireless Sensor Network

Investigation of different parameters on roll bonding quality of aluminium and steel sheets

One objective of the project ”Austrian Light Weight Structures (ALWS)” is a basic study of production, modelling and validation of roll bonded composites of AA6xxx-automotive alloy and IF-steel. In this context, the influence of surface preparation, pre-heating temperature of aluminium and steel sheet, and post-heat treatment on the bond strength of the composites is analysed by shear tests and reverse bend tests. Furthermore, the interface region is investigated by micro-hardness tests and metallographic observations.

A numerical investigation of different parameters that affect the performance of a flow conditioner

Recent work with computational fluid dynamics (CFD) tools has shown that this technique can help to improve flow conditioner and metering technology. In this study, CFD models are used to examine trends and provide insights into the velocity and turbulence field downstream of various flow conditioners installed in fully-developed flow. Several parameters which may affect turbulent mixing and flow conditioning downstream of a plate are studied. These include the overall porosity, the grading of porosity along the radius, the wetted perimeter and the number of holes in the plates. It seems that graded porosity is responsible for quickly obtaining a velocity profile close to being fully developed. The blocking area, which is correlated with porosity, is responsible for the pressure drop and the production of turbulent kinetic energy. The latter controls the mixing level and modifies the velocity profile further downstream. High turbulence levels downstream of the flow conditioner requires longer distance before the flow structure is 100per cent fully developed. This mechanism probably explains why the combined flow conditioners can be more efficient.