Opportunities and challenges in agriculture and garments

"For the past two decades, Bangladesh has enjoyed steady growth in per capita incomes enabling a significant reduction in poverty. An increase in rice productivity, achieved through a combination of improved seeds, increased fertilizer use, and public and private investments in irrigation, played a major role in the increase in incomes. Among the other major factors were a large expansion in textile exports, made possible by changes in world demand, Bangladesh trade liberalization, and macro-economic stability; and increases in workers remittances. In order to accelerate or even maintain income growth rates and poverty reduction, future policies must be carefully designed to capture the benefits and minimize the risks of international trade and a constantly changing international environment. A proper assessment of the impact of such policies and economic developments on the poor requires a comprehensive framework to analyze interactions between different sectors as well as linkages between macro and micro levels. In this paper we construct a social accounting matrix for 1999/2000 and develop a computable general equilibrium model (CGE) with special treatment of the rice and wheat sectors. We then present simulations of the effects of (i) rice productivity shocks, (ii) a decline in the world rice price, and (iii) a reduction in RMG exports, reflecting an end to preferential access to RMG markets for Bangladesh goods.... Overall, these simulations illustrate the importance of trade policy and links between Bangladesh and the world economy. International trade offers the potential to prevent a decline in real prices of rice if productivity of paddy production increases and to benefit from increased export earnings. It has also permitted a large increase in RMG export earnings. However, changes in international markets could threaten welfare of some Bangladesh households, as well, as illustrated by the simulations of lower import prices of rice that could sharply reduce farmer incomes, and of a decline in textile export earnings that could sharply reduce female urban employment and urban household incomes....[T]hese simulations show that the Bangladesh economy and household incomes are clearly linked with the global economy, particularly through foodgrain trade and the RMG sector. Efforts to alleviate poverty and raise the incomes of the poor should not neglect these linkages, particularly in cases where these poverty alleviation interventions are large enough to have major effects on the real exchange rate and female labor earnings." Author's Abstract.Equilibrium (Economics) Models ,

Modeling and estimation of internal friction in cloth

Force-deformation measurements of cloth exhibit significant hysteresis, and many researchers have identified internal friction as the source of this effect. However, it has not been incorporated into computer animation models of cloth. In this paper, we propose a model of internal friction based on an augmented reparameterization of Dahl's model, and we show that this model provides a good match to several important features of cloth hysteresis even with a minimal set of parameters. We also propose novel parameter estimation procedures that are based on simple and inexpensive setups and need only sparse data, as opposed to the complex hardware and dense data acquisition of previous methods. Finally, we provide an algorithm for the efficient simulation of internal friction, and we demonstrate it on simulation examples that show disparate behavior with and without internal friction

BxDF material acquisition, representation, and rendering for VR and design

Photorealistic and physically-based rendering of real-world environments with high fidelity materials is important to a range of applications, including special effects, architectural modelling, cultural heritage, computer games, automotive design, and virtual reality (VR). Our perception of the world depends on lighting and surface material characteristics, which determine how the light is reflected, scattered, and absorbed. In order to reproduce appearance, we must therefore understand all the ways objects interact with light, and the acquisition and representation of materials has thus been an important part of computer graphics from early days. Nevertheless, no material model nor acquisition setup is without limitations in terms of the variety of materials represented, and different approaches vary widely in terms of compatibility and ease of use. In this course, we describe the state of the art in material appearance acquisition and modelling, ranging from mathematical BSDFs to data-driven capture and representation of anisotropic materials, and volumetric/thread models for patterned fabrics. We further address the problem of material appearance constancy across different rendering platforms. We present two case studies in architectural and interior design. The first study demonstrates Yulio, a new platform for the creation, delivery, and visualization of acquired material models and reverse engineered cloth models in immersive VR experiences. The second study shows an end-to-end process of capture and data-driven BSDF representation using the physically-based Radiance system for lighting simulation and rendering

Multi-Scale Models to Simulate Interactions between Liquid and Thin Structures

In this dissertation, we introduce a framework for simulating the dynamics between liquid and thin structures, including the effects of buoyancy, drag, capillary cohesion, dripping, and diffusion. After introducing related works, Part I begins with a discussion on the interactions between Newtonian fluid and fabrics. In this discussion, we treat both the fluid and the fabrics as continuum media; thus, the physical model is built from mixture theory. In Part II, we discuss the interactions between Newtonian fluid and hairs. To have more detailed dynamics, we no longer treat the hairs as continuum media. Instead, we treat them as discrete Kirchhoff rods. To deal with the thin layer of liquid that clings to the hairs, we augment each hair strand with a height field representation, through which we introduce a new reduced-dimensional flow model to solve the motion of liquid along the longitudinal direction of each hair. In addition, we develop a faithful model for the hairs' cohesion induced by surface tension, where a penalty force is applied to simulate the collision and cohesion between hairs. To enable the discrete strands interact with continuum-based, shear-dependent liquid, in Part III, we develop models that account for the volume change of the liquid as it passes through strands and the momentum exchange between the strands and the liquid. Accordingly, we extend the reduced-dimensional flow model to simulate liquid with elastoviscoplastic behavior. Furthermore, we use a constraint-based model to replace the penalty-force model to handle contact, which enables an accurate simulation of the frictional and adhesive effects between wet strands. We also present a principled method to preserve the total momentum of a strand and its surface flow, as well as an analytic plastic flow approach for Herschel-Bulkley fluid that enables stable semi-implicit integration at larger time steps. We demonstrate a wide range of effects, including the challenging animation scenarios involving splashing, wringing, and colliding of wet clothes, as well as flipping of hair, animals shaking, spinning roller brushes from car washes being dunked in water, and intricate hair coalescence effects. For complex liquids, we explore a series of challenging scenarios, including strands interacting with oil paint, mud, cream, melted chocolate, and pasta sauce

Coupled Heating/Forming Optimization of Knitted Reinforced Composites

The feasibility of knitted fabric reinforcement for highly flexible composites has been investigated for the thermoforming process. The composite sheets were made through compression molding before being shaped. We used thermoplastic elastomers as matrices: Thermoplastic Elastomers and Thermoplastic Olefins. The knit reinforcement was provided by jersey knitted fabrics of polyester fibers. We first introduced the fundamentals involved in the study. The manufacturing is presented through compression molding and thermoforming. The latter is a two-step process: IR heating and plug/pressure assisted deformations. For the IR heating phase, several material properties have been characterized: the emissivity of matrices, absorption, reflection and transmission of radiations in the composite structure have been studied. We particularly paid attention to the reflection on the composite surfaces. The non-reflected or useful radiations leading to the heating are quantified and simulated for three emitter-composite configurations. It has been found that the emitter temperatures and the angle of incidence have significant roles in the IR heating phase. Thermal properties such as calorific capacity and thermal conductivity of the composites were also presented. Thermograms were carried out with an IR camera. Equipment and Thermogram acquisitions were both presented. Optimization of emitters was performed for a three emitter system. The objective function method has been illustrated.Regarding mechanical purposes, the characterizations of the matrices, reinforcements and flexible composites have been carried out. The studied loadings were uniaxial traction, pure shear and biaxial inflation. For the uniaxial extension, both the reinforcement and the composite were found highly anisotropic regarding the orientation of the loading toward the coursewise of the fabric. The resulting strains and stresses to rupture are also found anisotropic. However, for pure shear loading we observed isotropic behavior. Biaxial deformations have been studied; the stress-strain curves are closer to the ones from pure shear loading than from uniaxial traction. The stress and strains of the inflated disks were deduced from measurement on the deformed contours. A routine for contour extraction is presented. We pointed out that unreinforced matrices are strongly subjected to sudden polymer properties in biaxial deformation at certain temperatures. The stress-strain curves are affected by the resulting jumps in mechanical properties. On the other hand, the composites do not show those gaps in stress; the reinforcement rules the deformations. The thicknesses of inflated disks were also measured, fabric reinforcement is found to provide a better thickness repartition. It would be a major improvement for thermoformed good production. In order to predict the forming parameters (temperature, pressure, maximum deformation before rupture...), we introduced several hyperelastic models. They were used to simulate the stress-strain curves of the reinforced and non-reinforced elastomers for uniaxial traction, pure shear and biaxial loadings. Some material constants had been expressed and used as input for finite element simulations. Simulations have been introduced using first a direct stiffness method for a mass-spring assembly, then finite elements were presented and illustrated for the three studied deformations. Hyperelastic models were used. The fabric was simulated using one ANSYSTM code based on hexagonal elements. Pertinent results have been found for uniaxial and pure shear deformations. Regarding flexible composites, a fast method has been proposed based on cloth simulation technique

Cotton-textile-apparel sectors of India:

"Cotton, textiles, and apparel are critical agricultural and industrial sectors in India. This study provides descriptions of these sectors and examines the key developments emerging domestically and internationally that affect the challenges and opportunities the sectors face. More than four million farm households produce cotton in India, and about one-quarter of output is produced by marginal and small farms. Although production has expanded—most recently with the introduction of Bt (Bacillus thuringiensis) cotton—domestic prices dropped sharply in the late 1990s, in parallel to world cotton prices. Using partial equilibrium simulations, we estimate that a price movement of the magnitude that occurred has a significant effect on levels of poverty among cotton-producing households. The fiber-to-fabric production chain, from cotton processing through apparel, employs more than 12 million workers in India and provides 16 percent of export earnings. Except for the spinning industry, these sectors are dominated by small, fragmented, and nonintegrated units, which adversely affect their competitiveness. Recent policy reforms have induced some technological improvements. In terms of future prospects for the Indian processing, textile, and apparel industries, our analysis emphasizes three dimensions of reform—the need for further investments in human resource development to improve industry productivity and reduce poverty among workers in these sectors, the emergence of modern domestic retail marketing chains, and the potentially vibrant prospects for the industry that arise from a growing domestic fabric demand and new opportunities in world markets if appropriate policies and investments are undertaken." from authors' abstractCotton, textiles, Apparel, Rural poverty, subsidies, Industry policy, World markets,

Macro policies and the food sector in Bangladesh

Trade liberalization in the early 1990s in Bangladesh has enabled the private sector to respond with market-stabilizing inflows of rice and wheat following major production shortfalls. At the same time, easing of restrictions on foreign investment, combined with substantial depreciation of the Taka, have enabled exports of the labor-intensive ready-made garment industry to expand significantly. Moreover, recently discovered natural gas resources might be exploited, creating new revenues for the country. A proper assessment of the impact of such policies and economic developments on the poor requires a comprehensive framework to analyze interactions between different sectors, and linkages between macro and micro levels. In this paper we develop a computable general equilibrium model (CGE) with special treatment of the rice and wheat sectors, and we use it to simulate the impact of (i) a decline in rice production due to floods, (ii) a cut in food aid of wheat, and (iii) increased revenues from the exploitation of natural gas resources. The results suggest that most households benefit from more liberalized rice and wheat trade, particularly after rice production shocks. Impacts of a decline in wheat food aid are relatively modest, as food aid imports are not large enough to have major macroeconomic effects. The simulations of natural gas export revenues suggest that the extent of disincentives to agriculture will depend on whether or not the resulting real exchange rate appreciation is sufficient to lower the import parity price of rice enough so that domestic prices are affected. Finally, all three simulations show that the effects of economic shocks on women's labor and female headed poor households can differ significantly from the effects on men's labor and other households.Bangladesh ,Food production ,trade liberalization ,Female labor ,TMD ,

Technology enablers for the implementation of Industry 4.0 to traditional manufacturing sectors: A review

The traditional manufacturing sectors (footwear, textiles and clothing, furniture and toys, among others) are based on small and medium enterprises with limited capacity on investing in modern production technologies. Although these sectors rely heavily on product customization and short manufacturing cycles, they are still not able to take full advantage of the fourth industrial revolution. Industry 4.0 surfaced to address the current challenges of shorter product life-cycles, highly customized products and stiff global competition. The new manufacturing paradigm supports the development of modular factory structures within a computerized Internet of Things environment. With Industry 4.0, rigid planning and production processes can be revolutionized. However, the computerization of manufacturing has a high degree of complexity and its implementation tends to be expensive, which goes against the reality of SMEs that power the traditional sectors. This paper reviews the main scientific-technological advances that have been developed in recent years in traditional sectors with the aim of facilitating the transition to the new industry standard.This research was supported by the Spanish Research Agency (AEI) and the European Regional Development Fund (ERDF) under the project CloudDriver4Industry TIN2017-89266-R