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Waqas Ahmed

Bio: Waqas Ahmed is an academic researcher from University of the Sciences. The author has contributed to research in topics: Computer science & Supply chain. The author has an hindex of 9, co-authored 22 publications receiving 405 citations. Previous affiliations of Waqas Ahmed include National University of Science and Technology & National University of Sciences and Technology.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors developed a supply chain model that minimizes the total cost of a second generation biofuel supply chain and location-allocation for agricultural zones and biorefineries to meet the uncertain demand for market centers.

145 citations

Journal ArticleDOI
TL;DR: In this paper, the authors developed a three-echelon sustainable supply chain model in the context of multi-level trade credit and single-setup-multiple-delivery policy for mutual coordination in financial support and reducing carbon emissions.

82 citations

Journal ArticleDOI
TL;DR: In this paper, a multi-objective model is proposed to structure a sustainable supply chain for second-generation biofuel under a triple bottom line approach, where multiple agricultural regions, multiple biorefineries, transportation, and multiple markets are considered.
Abstract: Researchers have raised concerns that it is very essential to concentrate on sustainable and renewable energy resources to control the elevated level of global warming, which is a result of the enormous usage of fossil fuels. Biofuel is considered as an alternative solution for non-renewable sources for energy production. The assurance of this supply relies on a sustainable and efficient supply chain. For this study, a multi-objective model is proposed to structure a sustainable supply chain for second-generation biofuel under a triple bottom line approach. The proposed model captures a trade-off among conflicting objectives. The multiple agricultural regions, multiple biorefineries, transportation, and multiple markets are considered. The yield of residual biomass, the expense at agricultural regions, and the demand of markets are assumed uncertain and denoted by fuzzy numbers. The carbon tax and cap are incorporated into the supply chain model. The improved augmented e-constraint approach is employed to solve the proposed multi-objective optimization model. The objective of developed research is to design a sustainable supply chain framework which minimizes the total carbon emissions and total cost and maximizes the amount of new jobs opportunities in a second-generation biofuel. A numerical experiment is conducted, and the finding shows that the production cost of biofuel in the biorefineries contains a major proportion of the total cost. The transportation section is the predominant source for carbon emissions and a maximum number of jobs is accrued in rural areas. In-depth sensitivity analysis of this study is also performed to examine its actual application.

70 citations

Journal ArticleDOI
TL;DR: A green production quantity model with random imperfect quality items, trade-credit policy, service level constraints, and failure in reworking is developed to find the optimal green production and backordered quantity of each item such that the projected total cost is minimized.

67 citations

Journal ArticleDOI
TL;DR: In this article, a fuzzy green inventory model with non-instantaneous deteriorating products is presented to evaluate sustainable optimal ordering strategies for retailers, which maximize the entire annual profit and minimize the carbon emission.

55 citations


Cited by
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Journal Article
TL;DR: In this paper, the authors investigated the fate of BC applied to a savanna Oxisol in Colombia at rates of 0, 11.6, 23.2 and 116.1 t BC ha -1, as well as its effect on non-BC soil organic C.
Abstract: Black carbon (BC) is an important pool of the global C cycle, because it cycles much more slowly than others and may even be managed for C sequestration. Using stable isotope techniques, we investigated the fate of BC applied to a savanna Oxisol in Colombia at rates of 0, 11.6, 23.2 and 116.1 t BC ha -1 , as well as its effect on non-BC soil organic C. During the rainy seasons of 2005 and 2006, soil respiration was measured using soda lime traps, particulate and dissolved organic C (POC and DOC) moving by saturated flow was sampled continuously at 0.15 and 0.3 m, and soil was sampled to 2.0 m. Black C was found below the application depth of 0-0.1 m in the 0.15-0.3 m depth interval, with migration rates of 52.4 ± 14.5, 51.8 ± 18.5 and 378.7 ± 196.9 kg C ha -1 yr -1 (± SE) where 11.6, 23.2 and 116.1 t BC ha -1 , respectively, had been applied. Over 2 years after application, 2.2% of BC applied at 23.2 t BCha -1 was lost by respiration, and an even smaller fraction of 1% was mobilized by percolating water. Carbon from BC moved to a greater extent as DOC than POC. The largest flux of BC from the field (20-53% of applied BC) was not accounted for by our measurements and is assumed to have occurred by surface runoff during intense rain events. Black C caused a 189% increase in aboveground biomass production measured 5 months after application (2.4-4.5 additional dry biomass ha -1 where BC was applied), and this resulted in greater amounts of non-BC being respired, leached and found in soil for the duration of the experiment. These increases can be quantitatively explained by estimates of greater belowground net primary productivity with BC addition.

622 citations

Journal ArticleDOI
01 Feb 2019-Fuel
TL;DR: This review critically examines the various studies in literature that have explored nanoparticles in biofuel processes such as biohydrogen, biogas, biodiesel and bioethanol production, towards enhancing their process yields and elucidates the different types of nanomaterials that have been used in these bioprocesses.

237 citations

Journal ArticleDOI
TL;DR: It is shown that biomass for energy supply chain models must include the analysis of several different variables and include the main disadvantages of its use as well.
Abstract: The present study reviews the status of research on biomass supply chain modeling. Biomass has become increasingly important as a renewable alternative energy source. One of the most critical aspects associated with the use of biomass is its supply chain and all the elements that are part of it. Indeed, in order for the use of this type of energy resource to become viable, its supply chain, from collection and transport to storage and distribution, needs to be well structured and optimized. Modeling is a critical step in developing understanding that leads to improved supply chain efficiency. Thus far, investigations that utilize supply chain models have focused on assessing specific supply chain scenarios, usually with an objective of minimizing cost. Significant opportunity exists to improve and expand the modeling process to allow for efficient supply chain design and operation. During this article will be analyzed several models presented by recent research that approach different situations and scenarios. At the end it is shown that biomass for energy supply chain models must include the analysis of several different variables and include the main disadvantages of its use as well.

188 citations

Journal ArticleDOI
TL;DR: In this paper, a newsvendor inventory model in light of green product marketing of corporate social responsible firms is presented. And the expected profit function of the systems is formulated and maximized analytically.

145 citations

Posted Content
TL;DR: In this paper, an analytical framework for measuring the environmental performance of manufacturing supply chains was developed and deployed for the purpose of developing an innovative green supply chain performance measurement framework by integrating supply chain processes with organizational decision levels.
Abstract: The main purpose of this research is to develop and deploy an analytical framework for measuring the environmental performance of manufacturing supply chains. This work's theoretical bases combine and reconcile three major areas: supply chain management, environmental management and performance measurement. Researchers have suggested many empirical criteria for green supply chain (GSC) performance measurement and proposed both qualitative and quantitative frameworks. However, these are mainly operational in nature and specific to the focal company. This research develops an innovative GSC performance measurement framework by integrating supply chain processes (supplier relationship management, internal supply chain management and customer relationship management) with organisational decision levels (both strategic and operational). Environmental planning, environmental auditing, management commitment, environmental performance, economic performance and operational performance are the key level constructs. The proposed framework is then applied to three selected manufacturing organisations in the UK. Their GSC performance is measured and benchmarked by using the analytic hierarchy process (AHP), a multiple-attribute decision-making technique. The AHP-based framework offers an effective way to measure and benchmark organisations' GSC performance. This study has both theoretical and practical implications. Theoretically it contributes holistic constructs for designing a GSC and managing it for sustainability; and practically it helps industry practitioners to measure and improve the environmental performance of their supply chain.

128 citations