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Solar energy harnessing devices exhibit promising potential for providing a significant portion of the energy requirement. Among these devices, the solar parabolic trough collector (PTC) is a well-renowned and effective technology. In recent times, a great deal of research has been done further improving the thermal performance of PTC systems. The current numerical study investigates the effect of modifications to the geometry of the absorber tube and the effect of nanoparticles on the thermal performance of PTC. A corrugated tube (CT), sinusoidal corrugated tube (SCT), the corrugated tube having a cylindrical insert (CI), star insert (SI), and increasing diameter rod insert (IDRI) are used to modify the geometry of the absorber tube. The corrugated tube is also analyzed with water-Al2O3 and water-TiO2 nanofluids at volume concentrations of 2%, 4%, and 6%. The results showed that the sinusoidal corrugated tube produced the best results with a value of Nusselt number (Nu) being 15.2% greater than simple corrugated absorber tube without incurring any significant increase in pressure. Moreover, the performance evaluation criterion (PEC) value is also found to be greater than that of simple corrugated geometry. The use of nanofluids as the heat-transfer fluid (HTF) led to an overall enhancement in the heat transfer coefficient h by as much as 20%.

Date palm(Phoenix dactylifera)is commercially propagated through offshoots. Alongwith thisrooted offshootthe tree also produces aerial offshoots,which arerootlessand die after plantation. In this study attempts have been made to evaluate the effect of auxins on the root initiation of the aerial offshootsof date palm cv. Hillawi.Therefore, an experiment was conducted to evaluate theeffect of IAA (500 ppm), NAA(500 ppm), alone and in combination on root initiation in aerial offshoots of date palm cv. Hillawi. The auxins were applied to the aerial shoots by injection method. The experiment was laid out according to Randomized Complete Block Design (RCBD) with four treatments(Control, 500pmm IAA, 500ppm NAA and 500ppm IAA+NAA) andeach treatment was replicatedthrice.Injection method was used to apply the hormones and after the applicationof auxinsthe base of each offshoot was wrapped carefully with gunny bags having pinewood shaving as rooting media.After 40 days of supplication,offshootswere detached,and parameters were collected. Dataindicated that NAA @ 500ppm gave highest rooting percentage (24.5%), total number of roots per offshoot (82.33) and total weight of roots per offshoots (607.4g) as compared to other treatments. Similarly, a greaternumber of smaller roots (dia

Effective removal of excess heat from electronics equipment is the key to its intended functionality. A Defense Advanced Research Projects Agency (DARPA) hard problem is proposed in microtechnologies for the air-cooled heat exchangers (MACE) program that posed challenges to reduce the heat sink size fourfold while using only 50% of the current power budget. While numerous heat removal techniques have been proposed over the last several decades, synthetic jet actuator (SJA) is one of the leading candidates to create a game-changing cooling performance. This is due to its inherent advantages, such as size, low power consumption, ease of use, and affordability. This review article looks at different actuation methods (electromagnetic, piston cylinder, piezoelectric, and so on) to generate synthetic jet cooling. The performances of these approaches vary and need a procedure to unify the predictive capability. The performances are evaluated based on actuation (stroke length, operating frequency, and jet-to-heater spacing) and geometric parameters (shape and size of the cavity and the orifice). The flow characteristics and jet formation criterion are also discussed methods, and a critical commentary is added to normalize previous findings. Available correlations for predicting Nu numbers are evaluated and summarized through data sets for a possible unification. Finally, an empirical correlation is proposed based on available data using nonlinear regression via computational tools. To conclude, the challenges and research gaps are enumerated covering the fundamental and applied aspects of those jets for the implementation in electronics thermal management.

Zero forcing is a process of coloring in a graph in time steps known as propagation time. These graph-theoretic parameters have diverse applications in computer science, electrical engineering and mathematics itself. The problem of evaluating these parameters for a network is known to be NP-hard. Therefore, it is interesting to study these parameters for special families of networks. Perila et al. (2017) studied properties of these parameters for some basic oriented graph families such as cycles, stars and caterpillar networks. In this paper, we extend their study to more non-trivial structures such as oriented wheel graphs, fan graphs, friendship graphs, helm graphs and generalized comb graphs. We also investigate the change in propagation time when the orientation of one edge is flipped.

Indian jujube (Ziziphus mauritiana Lamk.) is a drought tolerant fruit crop and well adapted to sub-tropical to tropical climates. Seasonal pruning in jujube is essential to sustain the plants as productive with quality fruits because flowers and fruits are borne on young shoots of current season’s growth. This experiment was initiated and accomplished during 2016-18 to assess appropriate extent of pruning in various cultivars of Indian jujube with regard to productivity and fruit quality. Four cultivars of jujube i.e., Dehli Sufaid, Pak White, Umran and Alu Bukhara were subjected to four pruning levels i.e. no pruning, 25%, 50% and 75% pruning by removing unproductive, over-crowded secondary and tertiary branches leaving 3/4 (light), 1/2 (medium) and 1/4 (severe pruning) portion of branch intact with main limb, respectively. Experiment was laid out in randomized complete block design with three replications and statistically analysed in 2-factors factorial way. Pak White initiated new growth earlier (39 days), produced maximum branches per plant (77), shoots (15), panicles (63) and fruits (90) per branch, heavier (38 g) and bulky fruits (44 cm3), with minimum fruit drop (13%), higher yield (184 kg) per plant and fruits carrying the maximum pulp ratio (90%), total soluble solids (16 °Brix), vitamin C content (121 mg /100 g pulp) and total sugars (5.7%). Fifty percent pruning level proved more judicious in all jujube cultivars. Pak White performed the best when subjected to 50% pruning level for all the parameters under study as calculated by interaction between two factors.

In this study, conventional diesel fuel, pure Jatropha biodiesel, Jatropha-butanol blended fuel, and Jatropha biodiesel with fumigated butanol were tested in a single-cylinder direct-injection four-stroke diesel engine. The engine performance, combustion, and emissions were measured at 3600 rpm and brake power of 4.4 kW. For Jatropha, tests revealed that brake thermal efficiency was reduced by 5% and brake-specific fuel consumption was increased by 17% relative to diesel. An overall reduction in exhaust emissions (oxides of nitrogen, unburned hydrocarbons, and smoke opacity) was observed with the exceptions of carbon monoxide and carbon dioxide. For Jatropha-butanol blended fuel, the efficiency was increased by 2% relative to Jatropha; however, it was still 3% less than that of diesel. The fuel consumption was increased relative to both Jatropha and diesel. In terms of emissions, oxides of nitrogen and smoke opacity were reduced by 12.3% and 72%, respectively, with increased carbon monoxide and unburned hydrocarbon emissions compared to diesel fuel. For Jatropha with fumigated butanol, the efficiency was increased by 4% relative to Jatropha and decreased by mere 1% when compared to diesel. The fuel consumption showed a reduction of 1.4% when compared to Jatropha. A substantial decrease in opacity (85%), oxides of nitrogen (12.7%), and carbon dioxide (4%) emissions was recorded relative to diesel; however, carbon monoxide and unburned hydrocarbons were increased. It was concluded that butanol fumigation successfully improved the properties of Jatropha biodiesel and provided an overall better performance relative to blended fuel and neat Jatropha biodiesel.

Studies have previously looked at the transport processes in convection but there is a lack of detail on methods to characterize transient heat transfer behavior. An infrared methodology to spatial...

Mango being one of the most important fruit crops in Pakistan is facing a serious issue of malformation. If it is not treated, it renders great economical losses. Samar Bahisht Chaunsa is an excellent quality exportable cultivar of mango, but it is also the most vulnerable to inflorescence malformation. Therefore, the present study was carried out to address the malformation issue in mango cv. Samar Bahisht Chaunsa during 2016-18. The treatments comprised of pruning during March, pruning during April, pruning during March along with spray of Topsin-M @ 2 g L-1, pruning during April along with spray of Topsin-M @ 2 g L-1 and leaving plants un-pruned without spray as control. The tree branches were pruned up to 20 cm beneath the malformed inflorescences. Data on number of days taken to initiate growth, number of emerged flushes, number of bloomed flushes and number of malformed inflorescences were recorded. Pruning during March in combination with 2 g L-1 Topsin-M spray significantly affected all the parameters. The minimum number of days (37) taken for growth initiation, the highest number of emerged flushes (3.5) as well as bloomed flushes (3.2) along with the least number of malformed inflorescences (1.4) were recorded for the aforementioned treatment. Un-pruned and non-sprayed branches (control) did not initiate growth.

Microchannel heat sink is an effective method in compact and faster heat transfer applications. This paper numerically investigates thermal and hydraulic characteristics of a porous microchannel heat sink (PMHS) using various nanofluids. The effect of porosity (γ = 0.32–0.60), inlet velocity (win = 0.5–1.5 m/s), and nanoparticle concentration (ϕ=0.0025 – 0.05) on thermal-hydraulic performance is systematically examined. The result shows a significant temperature increase (40 °C) of the coolant in the porous zone. The pressure drop reduces by 35% for γ = 0.32 compared to the non-porous counterpart, and this reduction of pressure significantly continues when γ further increases. The pressure drop with win is linear for PMHS with nanofluids, and the change in pressure drop is steeper for nanofluids compared to their base fluids. The average heat transfer coefficient increases about 2.5 times for PMHS, and a further increase of 6% in h¯ is predicted with the addition of nanoparticles. The average Nusselt number Nu¯ increases nonlinearly with Re for PMHS. The friction factor reduces by 50% when γ increases from 0.32 to 0.60, and the effect of nanofluid on friction factor is insignificant beyond the mass flowrate of 0.0004 kg/s. Whilst Cu and CuO nanoparticles help to dissipate the larger amount of heat from the microchannel, Al2O3 nanoparticle appears to have a detrimental effect on heat transfer. The thermal-hydraulic performance factor strongly depends on the nanoparticles, and it slightly decreases with the mass flowrate. The increase of nanoparticle concentration, in general, enhances both h¯ and ΔP linearly for the range considered.

Lab scale combustion of solid fuels, such as biomass, is mostly performed using fixed bed combustors. Steady state data detailing various progress variables (temperature and emissions) are widely available within the literature. However, there is very little information available on how the onset of the steady state operation is identified especially in relation to batch operation, which is subject to depleting fuel bed. This paper uses experiments coupled with a systemic post-processing approach based on MATLAB in order to identify the onset of the steady state operation. The results show that by using both the percentile mean deviation and slope of certain measured progress variables (including the fuel bed temperature, freeboard temperature, fuel mass loss, and emissions) the steady state regime can be accurately predicted. The use of freeboard temperature data alone is not sufficient. Based on the methods developed, radiation error in thermocouple data was found to be significant in both non-staged and staged air combustion modes of fixed bed combustor. Moreover, the radiation error was lower for downstream thermocouples in contrast to upstream thermocouples.

Monsoon crop of guava is hit by fruit fly during July-August that results into huge loss to the producers. Spray of urea and Naphthalene acetic acid (NAA) is used to drop flowers and fruits of monsoon crop to get higher yield of winter crop. This study was carried out at Fruit Orchard of Horticultural Research Station, Bahawalpur during 2015-2017 to determine the optimum concentration of selected chemicals to drop flowers and immature fruits of monsoon crop. Plants with distilled water spray were treated as control (T1). Other treatments included urea @ 5% and 10% (T2 & T3), NAA @ 0.05 and 0.1% (T4 & T5) as 1st spray and repeated the same spray after fortnight, combination of urea (5%) as 1st spray followed by NAA (0.05%) as 2nd spray (T6) or urea (10%) 1st spray followed by NAA (0.1%) as 2nd spray (T7). Consolidated means of parameters over two years’ study indicated that the highest fruit yield (68.6 kg/plant), the maximum weight per fruit (168.3 g), number of fruit/plant (375), pulp content (55.5%), pulp thickness (1.05 cm), total soluble solids (14.3 °Brix), ascorbic acid content (176.7 mg / 100 g pulp) and total sugars (7.6%) were obtained as a result of highest flower drop (96.7%) and fruit drop (76.9%) with lowest fruit set (2.9%) from non-target monsoon fruiting in response to 0.1% NAA (T5) sprayed twice at fortnight interval, proceeded after the application of 0.05% NAA two spray fortnightly (T4). The plants under control remained at bottom with respect to parameters i.e. flower and fruit drop, at top with highest fruit setting in monsoon crop that led to the lowest yield of winter crop.

Investigations have been conducted into turbulent impinging jets but the exact flow dynamics and mechanisms leading to the observed heat transfer distributions at the impingement plane remain outstanding. In particular, use of different swirl generators (vanes, twisted inserts) means the role of varying inflow conditions (at the nozzle exit plane x/D = 0) should be studied to resolve its role on the observed convective heat transfer trends. The present paper studies axisymmetric turbulent weakly swirling (S = 0.31) jets (D = 40 mm) impinging onto a heated plate. Parameters varied include inflow conditions and the effects of impingement distance (H/D = 2, 4, and 6). The Reynolds Averaged Navier Stokes (RANS) equations are used to model the jets using the k-kl-ω turbulence model, which is benchmarked against other models. Three azimuthal ( ) velocity profiles at a Reynolds (Re) number of 24,600 are used at the nozzle exit plane: Uniform (UP), Solid Body Rotation (SBR), and Parabolic Profiles (PP). The start of the wall jet region, designated through elevated levels of turbulent kinetic energy correlates well with the widely observed first peak in Nu distribution. This is however extremely sensitive to the imposition of any swirl, with the application of even weak swirl (S = 0.31) minimally modifying flow dynamics (in the upstream jet region) and leading to recirculation zones stabilized at the impingement plane. This occurs in near-field impingement (H/D) for some inflow conditions (S031-UP), but not others thereby highlighting the significance varied nozzle and swirl generation methods on trends observed in the literature. The imposition of elevated levels of turbulence at the nozzle inflow (x/D = 0) appreciably modifies the heat transfer distribution, particularly in far-field impingement (H/D = 6).

Pomegranate is a drought tolerant fruit crop and is well adapted to sub-tropical and tropical climates. Fruit cracking is a major disorder in pomegranate which causes significant economic losses. In the present work, effect of foliar application of boric acid (0.05%), potassium nitrate (1.0%) and magnesium sulphate (1.0%) alone or in combinations was investigated to manage fruit cracking and improve fruit yield and quality of pomegranate cv. Golden. First treatment (foliar spray) was applied one month after fruit setting (April) and repeated twice during May and June each year. Application of foliar sprays affected fruit yield and quality positively. The maximum number of fruits per plant (254), average fruit weight (192 g), yield per plant (58.3 kg), number of arils per fruit (592), juice content (41.1%) as well as the minimum fruit cracking (3.9%) were recorded when 0.05% boric acid, 1% potassium nitrate and 1% magnesium sulphate were applied in combination. Fruit size and total soluble solids (TSS) of fruit juice were not affected by the applied treatments. Thus, combined application of boric acid, potassium nitrate and magnesium sulphate could be recommended for reducing fruit cracking and improving yield and quality of pomegranate fruits under semi-arid conditions of Southern Punjab, Pakistan.

In this paper, an optimal control problem of HIV infection model of delay differential equations is taken into account. Then we set a control function which represents the efficiency of reverse transcriptase inhibitors. Objective functional is constructed to minimize the virus concentration as well as treatment costs.Adjoint system is derived using Pontryagins Maximum Principle. Optimality system is calculated and numerical simulation is carried out to illustrate the theoretical results. Finally, conclusion is drawn

The aims and objectives of this manuscript are concerned with the investigation of some appropriate conditions to establish existence theory of solutions to a class of nonlinear four-point boundary value problem (BVP) corresponding to fractional order differential equations (FODEs) provided as $$\begin{aligned} \left\{ \begin{aligned} ^{c}&{\mathscr {D}}^{\omega }y(t)={\mathcal {F}}\left(t, y(t), {^{c}{\mathscr {D}}^{\omega -1}y(t)}\right),1

This manuscript is concerning to investigate numerical solutions for different classesincluding parabolic, elliptic and hyperbolic partial differential equations of arbitrary order(PDEs). The proposed technique depends on some operational matrices of fractional order differentiation and integration. To compute the mentioned operational matrices, we apply shifted Jacobi polynomials in two dimension. Thank to these matrices, we convert the (PDE) under consideration to an algebraic equation which is can be easily solved for unknown coefficient matrix required for the numerical solution. The proposed method is very efficient and need no discretization of the data for the proposed (PDE). The approximate solution obtain via this method is highly accurate and the computation is easy. The proposed method is supported by solving various examples from well known articles.

Growth in computational capacity combined with a decrease in the size of digital devices has led to increasing demand for more active and efficient cooling of electronics. In this study, an experimental investigation into two different sizes of central orifice Synthetic Jet Actuators (SJAs) is conducted to evaluate their heat transfer as well as noise generation characteristics. Two SJAs (40 mm and 20 mm) are examined, covering a distinct span of frequencies ranging from low to medium (

The computational power of microelectronic devices is increasing, which creates a need to dissipate more heat per unit area compared to the last decade. The recent development in electronics and the device sizes is shrinking, while circuit density is increasing.

Background: The recommended intake of fortified milk can substantially decrease the children’s ailment, increase growth rate and appears an economically beneficial strategy in the general Pakistani population aged over 6-24 months. Objective: The aim of this study is to determine the influence of fortified milk on children's health in Pakistan. Study Design: Randomized controlled trial. Settings: Department of Economics, GC University, Faisalabad-Pakistan. Duration: April 2019 to August 2019. Sample Size: Consisted of 100 individuals. Sampling Technique: Snowball technique was used to collect data. Data Analysis: Pretest and posttest data were analyzed with the help of t-test, paired sample t-test, and cross-tabulation. Results: It was found that there was a significant difference between the mean difference in age, height ratio of participants from their pretest and post-test scores. Conclusion: Fortified milk brings positive changes in growth of children in terms of weight & height. Suggestions: The mass should have awareness regarding fortified complementary foods.

Circumcision is the commonest surgical procedure carried out on children. Neonatal circumcision rates vary widely between different cultures, with rates as high as 64% in North America, between 10% and 20% in Australia, and far lower rates in Europe and Asia. It is also undertaken on medical grounds with benefits thought to include improved hygiene, a reduced incidence of urinary tract infection (UTI), sexually transmitted diseases, penile cancer, and phimosis, and a reduction in the incidence of human papilloma virus related cervical cancer in female sexual partners. Objective: To determine the frequency of urinary tract infection (UTI) in uncircumcised infants. Study Settings: Pediatric Ward, Emergency and OPD, Allied Hospital, Faisalabad Study Design: Descriptive cross sectional study Duration Of Study: Six months after the approval of synopsis Methodology: After the approval to carry out this study from Ethical Review Committee, all male uncircumcised subjects meeting the inclusion and exclusion criteria were included in the study. Written informed consent was taken from the patients. Data regarding the disease, presenting complaints and other relevant data according to questionnaire were collected after complete examination of the child. Age, weight, temperature, history of previous UTI, dysuria, and colour and urine was noted. Urine sample was collected in a sterile container with the help of the parents and sent to the lab for complete examination and culture. Relevant baseline investigation was also sent to the laboratory for examination. Results of the urine complete examination and urine culture were also noted. Results: In this trial, mean age was calculated as 6.81+2.44 months, mean temperature and weight of the infants was recorded as 99.26+1.06F and 7.06+1.85 kgs respectively. Frequency of history of dysuria was recorded in 30%(n=30), frequency of previous history of UTI was recorded in 13%(n=13), frequency of UTI was recorded in 25%(n=25). Conclusion: We concluded that the frequency of urinary tract infection (UTI) is higher in uncircumcised infants, however, timely circumcision may reduce the risk of UTI. The current data is primary in our population which needs authentication through some other trials. Keywords: Infants, circumcision, urinary tract infection (UTI)

This paper addresses both the upstream and downstream flow domain in turbulent impinging jets, which have widespread applications in cooling, heating, and drying. The role of impingement on swirl induced vortex breakdown as well as the interplay between heat transfer (at the impingement plane) and the downstream flow domain are analysed. Particle Image Velocimetry (PIV) is used to resolve the flow field in a range of jets, covering three Reynolds numbers (Re = 11,600, 24,600, and 35,000), two swirl numbers (S = 0.3 and 0.74), and two impingement distances (H/D = 2 and 4) as well as free jets. With regard to the upstream flow field at low swirl (S = 0.3), both free and impinging jets do not exhibit vortex breakdowns. However, for high swirl (S = 0.74), vortex breakdown in the upstream is observed at Re = 11,600 and Re = 24,600, but not Re = 35,000. Impingement distance affects the size, position, and strength of the recirculation bubble (vortex breakdown). The recirculation bubble is more spherical and stronger at Re = 11,600 in contrast to the Re = 24,600. Near-field impingement (H/D = 2) significantly affects the size and shape of the bubble. In free jets, the width of the vortex breakdown bubble at Re = 11,600 spans −0.4

In this research article, a new mathematical delayed human immunodeficiency virus (HIV-1) infection model with two constant intracellular delays, is investigated. The analysis of the model is thoroughly discussed by the basic reproduction numbers $ R_{0} $ and $ R_{s} $. For $ R_{0}

A multitude of research has already been undertaken to examine the effects of imparting swirl (S), Reynolds number (Re), and nozzle-to-plate distance (H/D) on the steady-state heat transfer characteristics of turbulent impinging jets. However, no studies to date have compared the transient development of such jets in both swirling and non-swirling conditions. The current paper addresses this gap by using highly resolved (time series) imaged (infrared) data in conditions spanning Re = 11,600, 24,600, and 35,000. The experiments are based on an electrically heated foil (0.025 mm) with jets over S = 0–1.05 and nozzle-to-plate-distances of H/D = 2, 4, and 6. For non-swirling impinging jets, at greater Reynolds numbers, the location of the highest Nusselt number remains fixed for all the time steps in contrast to jets with low Reynolds number. The transient characteristics for H/D = 4 are distinct compared to H/D = 2 and 6, with impingement heat transfer taking more time to reach steady-state for H/D = 4. It is also seen that heat transfer distribution over the impingement plate changes significantly over the small interval of time. For swirling jets, the impingement plate heat transfer characteristics develop simultaneously for the stagnation and wall jet region. The peak Nusselt number shifts to the wall jet region as the intensity of swirl increases. Two correlations (first for non-swirl and low-swirl, later for moderate to high swirl) are proposed to predict the time needed to reach steady-state for Re = 35,000.

Due to copyright restrictions, the access to the full text of this article is only available via subscription. As electronic devices are becoming more compact each day, the more effective and efficient active cooling technologies are needed. Microfluidic devices, such as synthetic jets, serve as a potential candidate to fulfill the thermal management needs of the next generation electronics. An experimental and computational study has been performed for circular central-orifice synthetic jets. First, a series of experiments was performed to quantify the actuator deflection, air velocity, heat transfer augmentation, and power consumption for central-orifice synthetic jets. Later, a computational study was performed utilizing the same boundary conditions in order to predict the deflection of the diaphragm. The experiments were conducted on three different types of synthetic jets, namely, low-, medium-, and high-frequency synthetic jets. Although a number of correlations were proposed for the prediction of Nu number for slot synthetic jets, no correlation was found to predict the average Nu number for a synthetic jet with a round orifice. Therefore, two correlations were developed, one for low- and medium-frequency synthetic jets and the other for high-frequency synthetic jets to predict the heat transfer coefficient as a function of the geometry, position, and operating condition for impinging flows. The proposed correlations are able to predict the impingement heat transfer of a synthetic jet with an accuracy of ±25% for a wide range of operating conditions and geometrical variables. Normalized frequency had the minimum impact on the average Nu number of a high-frequency synthetic jet compared with dimensionless distance, both have moderate impact on low- and medium-frequency jets. TÜBİTAK ; Istanbul Development Agency