Economic Analysis of Rubber Agroforestry Systems in Ghana

Even though rubber contributes massively to Ghana’s economy, smallholder rubber farmers’ inability to wait for about 6-8 years to see the benefits constrains establishment and expansion of the rubber subsector. To lessen the waiting time to the benefits, an option exists to intercrop rubber with food crops. Cost benefits analysis of rubber/plantain intercropping system under different treatments on two experimental plots for sole crop plantain (P) and three intercropping treatments consisting of one (PR), two (PPR) and three (PPPR) rows of plantain each between two rows of rubber each were carried out to assess the most viable. Analysis using discounted cash flow was used to determine the benefit/cost ratio (BCR), net present value (NPV) in addition to internal rate of return (IRR) at 25 % interest rate. All the rubber/plantain intercropping systems (PR, PPR and PPPR) were found to be profitable from the results. The highest return of GHȻ40, 331 (USD 9,379) per hectare from plantain over the period of two years was realized from the PPPR cropping system. Additional analysis performed to assess the profitability of rubber/plantain intercropping systems by varying the price of plantain, discount rate and the total cost of production showed that the systems were all profitable. The PPPR was the most profitable with the highest income to smallholder farmers. Extension education by the government through the Ministry of Food and Agriculture and Ghana Rubber Estates Limited and support to rubber farmers to access credit can help in farmers’ adoption of rubber agroforestry system

Nanomaterials in 2 dimensions for flexible solar cell applications a review

This review presents the progress, challenges and prospects of ultrathin flexible photovoltaic devices based on 2 dimensional 2D nanomaterials. These devices have shown very high performance in bending stabilities for up to 90 of their power conversion efficiencies PCEs after multiple bending deformations. They are thin film PVs with lightweight and mechanically robust structures that allow use in the continual advancing solar cell applications. In this paper, comprehensive assessments of 2D nanomaterials, their syntheses methods, performance, degradation, mechanical and opto electronic characterization in flexible photovoltaic PV cells are highlighted. Semi conductor materials such as conjugated donor and acceptor polymers, small donor acceptor molecules and organometal halide perovskites for use as active layers in such flexible solar cell structures are reviewed. The challenges and prospects associated with the adoption of 2D nanomaterials in flexible solar cells are presented. The review highlights the need to transition laboratory results on 2D nanomaterials based flexible solar cells into scale up and commercialized products despite the existing and also opens research areas for researchers to explore and achieve robust and high efficient solar device

Rubber and plantain intercropping: Effects of different planting densities on soil characteristics

Two field experiments were conducted at Ellembelle and Jomoro districts in the Western region of Ghana where rubber cultivation is a predominant farming activity. The objective of the study was to assess the effect of rubber and plantain intercropping systems on selected soil properties. The experiment was arranged in a randomized complete block design (RCBD) with 3 replications. The treatments were the sole crop rubber (R), sole crop plantain (P) and three intercrop systems comprising an additive series of plantain: one row of plantain to one row of rubber (PR), two rows of plantain to one row of rubber (PPR) and three rows of plantain to one row of rubber (PPPR). Generally, agroforestry systems improved the soil hydraulic properties considerably, with the highest cumulative infiltration rates of 5.16 and 8.68 cm/min observed under the PPPR systems at the Ellembelle and Jomoro sites, respectively. Microbial biomass C (Cmic), N (Nmic) and P (Pmic) was significantly improved (P < 0.05) under the agroforestry than the monocrop systems. The Cmic, Nmic and Pmic values were highest under the PPPR system at both Ellembelle (Cmic, = 139.9 mg/kg; Nmic = 36.26 mg/kg and Pmic = 87.6 mg/kg) and Jomoro (Cmic = 78.7 mg/kg; Nmic = 80.3 mg/kg and Pmic = 3.45 mg/kg) sites

Effects of pre-buckling on the bending of organic electronic structures

This paper explores the extent to which pre-buckling of layers (in thin film multilayered structures) can be used to increase the flexibility of organic electronic devices. The deformation of wavy/buckle profiles, with a range of nano- and micro-scale wavelengths, is modeled using finite element simulations. The predictions from the models are then validated using experiments that involve the bending of layered structures that are relevant to flexible organic electronics. The introduction of pre-buckled profiles is shown to increase the range of deformation that is applied to model structures, prior to onset of significant stresses and strains. The implications of the work are discussed for the design of robust flexible organic solar cells

Preparation and Characterization of Rubber Blends for Industrial Tire Tread Fabrication

The physico-mechanical properties of variable rubber blends including epoxide natural rubber (ENR), polybutadiene rubber (BR), and solution polymerized styrene-butadiene rubber (SBR) filled with silanized silica and carbon black mixtures were explored. The tensile, hardness, resilience, abrasion, and fatigue behavior were investigated. An optimized composition involving 30 phr of ENR and 70 phr SBR filled with mixtures of carbon blacks and silanized silica was proposed to be a suitable composition for the future development of green passenger truck tires, with low rolling resistance (fuel saving ability), high wear resistance, and desired fatigue failure properties

Cold welding of organic light emitting diode: Interfacial and contact models

This paper presents the results of an analytical and computational study of the contacts and interfacial fracture associated with the cold welding of Organic Light Emitting diodes (OLEDs). The effects of impurities (within the possible interfaces) are explored for contacts and interfacial fracture between layers that are relevant to model OLEDs. The models are used to study the effects of adhesion, pressure, thin film layer thickness and dust particle modulus (between the contacting surfaces) on contact profiles around impurities between cold-welded thin films. The lift-off stage of thin films (during cold welding) is then modeled as an interfacial fracture process. A combination of adhesion and interfacial fracture theories is used to provide new insights for the design of improved contact and interfacial separation during cold welding. The implications of the results are discussed for the design and fabrication of cold welded OLED structures

Pressure effects on interfacial surface contacts and performance of organic solar cells

This paper explores the effects of pressure on the interfacial surface contacts and the performance of organic solar cells. A combination of experimental techniques and analytical/computational models is used to study the evolving surface contacts profiles that occur when compliant, semi-rigid and rigid particles are interlocked between adjacent layers in model solar cell structures. The effects of layer surface roughness and interlocked (trapped) particles are also considered along with the effects of surface energy, adhesion energy, and pressure. The results show that increased interfacial contact lengths and decreased void lengths are associated with the application of increased pressure. Increased pressure also results in significant improvements in power conversion efficiency. These improvements in power conversion efficiency are associated with the closure up of micro- and nano-voids due to the application of pressure to layers produced via spin coating and thermal evaporation. The results suggest that pressure-induced contacts can be used to enhance the performance of organic solar cells