Morpho-palynological investigation of gymnospermal flora from subalpine and alpine zones of northern Pakistan using LM and SEM

The pollen morphology, with special reference to exine sculpture, of some species of the gymnosperms was assessed for the first time from the subalpine and alpine zones of western Himalayas northern Pakistan. The pollen of all these species is airborne and allergenic, so pollen morphology helps for identification of this allergenic pollen at specific level. Different morpho-palynological characteristics were analyzed including size range of pollen, polar and equatorial diameter ratio, exine ornamentation, sculpturing, exine thickness, pollen type, and shape. For accurate and quick identification of species, taxonomic key was made based on different morpho-palynological characteristics. The quantitative data were processed using SPSS software. Gymnospermal pollen includes inaperturate, rarely 1-colpate observed in (Cupressaceae), hexazonocolpate in (Ephedraceae), vesiculate, bissacate in (Pinaceae), and inaperturate in (Taxaceae). Different pollen shapes observed were prolate (4 spp), sub-spheroidal (7 spp), and oblate (1 spp). Variation was observed in exine sculpturing granular (4 spp), reticulate (1 spp), areolate-punctate (3 spp), and psilate (2 spp). This is based on the analysis of 10 plants belonging to four families of gymnosperms. Distinct pollen shape has emerged as the most diagnostic feature to separate some genera such as spheroidal in (Cupressaceae, Taxaceae), prolate and radiosymmetrical in (Ephedraceae), and bilateral in (Pinaceae). Exine thickness and sculpturing proved to be helpful at generic and specific levels. The results reinforced the significance of gymnospermal pollen morphological features which were used as aid for valuable taxonomic tool in plant systematics.     

A Preliminary Study on WO3‐Infiltrated W–Cu–ScYSZ Anodes for Low Temperature Solid Oxide Fuel Cells

Preparation and electrochemical characterization of WO₃‐infiltrated 0.48W–0.52Cu–ScYSZ (WCS) anode for solid oxide fuel cell are reported. The DC conductivity of a WO₃ ceramic was 1,200 and 24 S cm^–1 in reducing and oxidizing atmospheres, respectively, at 650 °C. WCS porous backbones in the form of symmetric cells were prepared by screen printing of WO₃–CuO–ScYSZ ink and subsequent sintering at 1,300 °C for 1 h in 9% H₂/N₂. Analysis of the sintered backbone by X‐ray diffraction showed the metallic W and Cu phases. Precursor solutions of WO₃ or CuO were infiltrated into porous WCS backbones to form the anode. The electrochemical performance of these anodes measured by impedance spectroscopy showed polarization resistances of 11 and 6.5 Ω cm² for WO₃ and CuO infiltrated anodes, respectively, at 600 °C in humidified hydrogen. Activation energy values of 86.8 and 96.5 kJ mol^–1 were obtained for WO₃ and CuO infiltrated WCS anodes, respectively. The microstructure of the tested anodes showed well‐dispersed sub‐micron particles of WO₃ in the WCS backbone whereas CuO infiltration resulted in a dense microstructure.     

Polyhexamethylene Biguanide Functionalized Cationic Silver Nanoparticles for Enhanced Antimicrobial Activity

ABSTRACT: Polyhexamethylene biguanide (PHMB), a broad spectrum disinfectant against many pathogens, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles. The particles formed were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering (DLS), electrophoretic mobility and TEM to measure their morphology and surface chemistry. PHMB-functionalized silver nanoparticles were then evaluated for their antimicrobial activity against a gram negative bacterial strain, E. coli. These silver nanoparticles were found to have about 100 times higher bacteriostatic and bactericidal activities, compared to the previous reports, due to the combined antibacterial effect of silver nanoparticles and PHMB. In addition to other applications, PHMB-functionalized silver nanoparticles would be extremely useful in textile industry due to the strong interaction of PHMB with cellulose fabrics.     

Numeric and experimental study of generalized geometrical design of a hydrodynamic journal bearing based on the general film thickness equation

This paper deals with multi-objective shape optimization related to the geometrical design of a hydrodynamic journal bearing. The aim proposed here is to show that optimum shape design with better performance could surpass the limitations of existing bearing profiles. Attempting to remove the difficulty of selecting the weighting factor in multi-objective journal bearing optimization problems, a modified non-dominant sort in genetic algorithm was used as an optimization tool with a penalty to those solutions that violate constraints. Three kinds of optimized shapes were manufactured and taken as experimental objects. Experimental apparatus was described and some experimental data was presented. The comparison was made for the optimized bearings between numeric values and experimental data. The results show that the new method for shape optimization of hydrodynamic journal bearings based on the general film thickness equation is feasible.     

Smallholders’ access to agricultural credit in Pakistan

The Government of Pakistan has implemented a policy of food security for smallholders by making provision of credit needed for purchasing inputs such as farm machinery, fertilizer and seed. This study analyzed access to and adequacy of credit for smallholders with landholdings up to 5 acres (= 2 ha), using primary data collected through a survey of 208 households, focus-group discussions and unstructured interviews. The findings revealed a partial success of the national credit policy in terms of the proportion of households having access to formal credit but appeared less successful when this was compared with the total amount of credit demanded and obtained. Among the three types of smallholders compared, i.e. lower-smallholders (≤1.0 acre), middle-smallholders (1.01–2.50 acres) and upper-smallholders (2.51–5.00 acres), the lower-smallholders obtained least benefit from the policy as reflected in the formal credit accounting for 12% of the total credit obtained and only 6% of the total credit demanded. The other two types of smallholders had relatively better access to formal credit. Due to a lack of access to adequate formal credit, informal sources have continued to play a major role in the credit market. The causes for this are explained and relevant policy recommendations are made for improving smallholders’ access to credit in the study area and elsewhere in Pakistan. It is hoped that the findings of this study will make a useful contribution to the understanding and remedying of the difficulties that smallholders experience in obtaining credit which may be of value not only in Pakistan but in other developing countries.     

A combined analytical hierarchical process (AHP) and Taguchi experimental design (TED) for plastic injection molding process settings

Injection molding process is without doubt a multi-objective process if processing time, productivity, effectiveness, and the multi-criteria quality of the product are taken into consideration. Process settings affect the degree by which these objectives are realized. This work suggests a new proposal for evaluating optimal process settings through the handling of the plastic injection molding process in the same approach as a traditional multi-objective multi-criteria process. In a sense, there are numerous objective functions including cooling time, volumetric shrinkage, warpage, sink marks, residual stresses, and various process settings including temperature, pressure, etc. Within the suggested proposal, the Taguchi experimental design is used to generate a balanced set of experiments to explore the process; then, the finite element software SIMPOE is used to evaluate the behavior of the injection molding at each experimental setting. Analytical hierarchical process is then employed for multiple comparisons of the objectives and experiments as such to give the overall objective weight for each process setting (experiment). Analysis of variance is then used to evaluate the significant factors and the optimal setting of the process. This technique proved effective to obtain compliance between process design and several common manufacturer preferences, although the considered part was not changed.     

Influence of Different CH4/N2 Ratios on Structural and Mechanical Properties of a-CNx:H Film Synthesized Using Plasma Focus

Carbon nitride films were synthesized by operating the dense plasma focus device with different CH₄/N₂ admixture gas ratios and fixed 20 focus shots. The pressure and axial distance from anode tip were kept constant at 3 mbar and 8 cm respectively. Raman and X-ray photoelectron spectroscopy (XPS) techniques were used to observe the effect of CH₄/N₂ ratio on carbon nitride bonding. The XPS analysis showed that the terminating group C≡N is more dominant for the films synthesized using higher concentration of nitrogen which gives softer films. Field emission scanning electron microscopy results showed that the deposited films consist of nanoparticles and their agglomerates. The size of agglomerates increases with decreasing concentration of nitrogen in CH₄/N₂ admixture gas. Nanoindentation results showed the increase in hardness and elastic modulus values of films with decreasing concentration of nitrogen in CH₄/N₂ admixture gas. The hardness and elastic modulus values were found to be dependent on sp³ content in the film as well as the C≡N. The hardness and elastic modulus values of 10.7 and 229.8 GPa respectively were achieved for the films deposited with fixed 20 focus deposition shots and using CH₄/N₂ admixture gas ratio of 7:3.     

Statistical model for predicting the air permeability of polyester/cotton-blended interlock knitted fabrics

Little information is available in the literature about double-rove spun yarn's low-stress mechanical properties. An experimental investigation has been made in a short-staple spinning system to study the effect of strand spacing, twist, and spindle speed on a double-rove yarn's compressive resilience, and compressibility at low-stress levels. The response-surface equations developed from the experimental results, have been used to explain the compressional behaviour of the yarn studied.     

Modeling the mechanical and compression properties of polyamide/elastane knitted fabrics used in compression sportswear

A compression sportswear fabric should have excellent stretch and recovery properties in order to improve the performance of the sportsman. The objective of this study was to investigate the effect of elastane linear density and loop length on the stretch, recovery, and compression properties of the weft-knitted polyamide/elastane (PA/EL) stretchable fabrics used in sportswear. Two different tests were performed to study the stretch and recovery properties of the fabric 1st: under low power force and 2nd: cyclic loading under high tension force. Kikuhime pressure sensor was used to measure the pressure generated by different PA/EL knitted sample garment sleeves. It was found that with the increase in elastane linear density there is an increase in fabric course density, areal density, recovery percentage, and compression, and fabric stretch percentage and elongation percentage decreased in both course and wale direction. The results of fabric samples were analyzed in Minitab statistical software. The coefficients of determinations (R² values) of the regression equations showed good prediction ability of the developed statistical models.     

Impact of forecasting methods on variance ratio in order-up-to level policy

This paper considers the impact of forecasting methods on the bullwhip effect for a simple replenishment system in which a first-order autoregressive process describes the customer demand and an order-up-to inventory policy characterizes the replenishment decision. The impact of exponential smoothing and minimum mean squared error forecasting is measured for both the bullwhip effect and inventory variances. Previous similar studies have focused on investigating the impact of forecasting methods on bullwhip effect. However, little research has been carried out to explore the impact of forecasting methods for both bullwhip effect and inventory variances. Through simulation experiments, it has been found that depending on the structure of the demand process, the appropriate selection of forecasting technique can reduce, or even eliminate (i.e., “dewhip”) the bullwhip effect. However, in terms of inventory variances it has been shown that the inventory variances for the exponential smoothing are greater than the minimum mean squared error forecasting method and that gap increases as lead time increases. These findings will help companies to choose the appropriate forecasting technique depending on the nature of demand. These guidelines can help companies to reduce the bullwhip effect and inventory variances across supply chain.