Sharif Digital Repository

In this paper we develop a stochastic programming approach to solve a multi-period multi-product multi-site aggregate production planning problem in a green supply chain for a medium-term planning horizon under the assumption of demand uncertainty. The proposed model has the following features: (i) the majority of supply chain cost parameters are considered; (ii) quantity discounts to encourage the producer to order more from the suppliers in one period, instead of splitting the order into periodical small quantities, are considered; (iii) the interrelationship between lead time and transportation cost is considered, as well as that between lead time and greenhouse gas emission level; (iv)... 

The maritime inventory routing problem (MIRP) has gained attention in several aspects during the last decades. The problem has numerous variations, typically instigated from real-world complications. This paper addresses MIRP to meet demand in different ports within the defined planning horizon. A mixed integer nonlinear programming model is developed with respect to different planning and routing constraints, loading/unloading restrictions, wave and wind forces limitations, tide constraints, and ship capacity constraints. To study the effects of wave angle, wind force, and tide, the top ten important ports in Iran and nearby ports have been considered as a sample. Optimization of the ship... 

Inventory management of deteriorating items faces major challenges by uncertain demand, uncertain lead time, perishability, and high customer service level requirements. So, this issue is extremely important in many corporations today. The periodic up-to level policy for deteriorating products under stochastic demand and stochastic lead time is not paid enough attention up to now. In this paper we propose a new approach to study inventory up-to level policy of deteriorating products under normal distributed demand and lead time by considering service level requirements. To model deterioration process, a non-linear increasing holding cost function is considered. After developing the... 

Although managing and controlling the inventories of perishable products is progressively becoming more important, they are often neglected in lot-sizing research and modeling. This paper studies a new multi-product multi-period dynamic lot sizing problem, where the inventories of products are assumed to be expired at a pre-specified date. For this purpose we assume a retailer that purchases products in large quantities (lot size) from manufacturers, and then sells smaller quantities (or single units) to the consumer. So, the order quantities can be merely an integer multiplier of that product batch size. The retailer also owns a capacitated warehouse. In order to make decisions on "how much... 

In recent years consumers and legislation have been pushing companies to design their activities in such a way as to reduce negative environmental impacts more and more. It is therefore important to examine the optimization of total supply chain costs and environmental impacts together. However, because of the recycling of deteriorated items, the environmental impacts of deteriorating items are more significant than those of non-deteriorating ones. The objective of this paper is to develop a stochastic mathematical model and to propose a new replenishment policy in a centralized supply chain for deteriorating items. In this model, we consider inventory and transportation costs, as well as... 

Photovoltaic (PV) panel accurate modeling is essential for operational studies and generation estimation under actual conditions and power electronic control device designs in grid connected or isolated power systems. Inaccuracy in modeling parameters such as photon's current, diode's saturation current, series and parallel resistances and diodes ideality coefficients causes errors in modeling and simulating photovoltaic panel's operation. In this paper, photovoltaic panel's parameters are estimated according to characteristic curves obtained from experiments. Heuristic optimization methods are utilized to calculate parameters for both singlediode and double-diode models. Results indicate... 

Background: The development of colon cancer has been described as a multistep process of carcinogenesis. Understanding molecular and cellular changes underlying this process is required to determine potential biomarkers and therapeutic targets in colon cancers. Several molecular entities, including glypicans, are implicated in cancer development. Among these is glypican-6, which is overexpressed in a limited number of cancers. This study aims to characterise the glypican-6 expression in different types of colon cancer. Methods: Immunohistochemistry was used to characterise glypican-6 expression in a panel of archived formalin-fixed, paraffin-embedded colon tissue types. These types included... 

Purpose: To evaluate the phytochemical profile of methanol extract of Ephedra foeminea and assess its anti-carcer effect on a large set of normal and cancerous cell lines Methods: Extraction of air-dried powder of aerial parts of E. foeminea was carried out with methanol. The bioactive compounds in the extract were determined using gas chromatography/mass spectrometry (GC-MS). The anti-cancer effect of the extract was determined by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay against various types of normal and cancer cell lines. Serial concentrations of plant extract were used, ranging from 7.812 to1000 μg/mL. Doxorubicin (DOX) served as standard drug. The... 

There exist various service systems that have hierarchical structure. In hierarchical service networks, facilities at different levels provide different types of services. For example, in health care systems, general centers provide low-level services such as primary health care services, while the specialized hospitals provide high-level services. Because of demand congestion in service networks, location of servers and allocation of demand nodes have a strong impact on the length of queues at servers as well as on the response times to service calls. The thrust of this article is the development of hierarchical location-allocation models for congested systems by employing queueing theory... 

Many developed models for deterioration items considered only costs related to inventories. Recently consumers and legislation have pushed companies to design their activities in order to reduce more and more the negative environmental impacts. Thus, it is important to examine the optimization of total supply chain costs and environmental impacts together. However, because of the recycling of the deteriorated items, the environmental impacts of supplying deterioration items are more significant than the non-deterioration products. The objective of this paper is developing a mathematical model and proposing a new replenishment policy in a centralized supply chain for deterioration items. In... 

This paper proposes a robust investment and operation model to attend the power and heat needs of a microgrid (MG) connected to the distribution system. The optimization algorithm decides on the best investment and operation of combined heat and power (CHP), boilers, PV power generation and battery energy storage systems (BESS). For the BESS, the algorithm estimates the optimal energy storage capacity (MWh) as well as the maximum hourly delivery capacity (MW). The non-linear and non-concave heat rate chart is recast by a mix-integer linear model to have a tractable and precise model. The model considers the uncertain in some parameters using probability density function (pdf) to portrait its... 

Study Design. A cross-sectional study to quantify trunk motor control during multidirectional isometric tracking tasks.Objective. To investigate the effect of chronic low back pain (LBP) on trunk neuromuscular performance while participants performed isometric exertions of trunk muscles to track targets in different angles with various magnitudes.Summary of Background Data. Tracking tasks especially in multidirectional activities are among the common research methods to quantify human motor control in different conditions. However, little information is available on trunk motor control during these tasks. There is no study investigating trunk accuracy during multidirectional isometric... 

With the application of chemical enhanced oil recovery methods, water separation is a major issue in a production facility. Oil/water separation is suppressed with a stable emulsion. The present study evaluated the impact of different emulsifiers in enhanced oil recovery. The effectiveness of each additive such as an alkali, surfactant, or polymer on the stability of the emulsion was anticipated using laser scattering to measure the emulsion’s stability. An artificial neural network was applied to predict the effectiveness of the additives on stabilization/destabilization and to assess how alkali/surfactants, surfactant/polymers, and polymer/surfactants affect the separation profiles.... 

Accumulation of amyloid beta (Aβ) soluble forms in the cerebral parenchyma is the mainstream concept underlying memory deficit in the early phase of Alzheimer's disease (AD). PKMζ plays a critical role in the maintenance of long-term memory. Yet, the role of this brain-specific enzyme has not been addressed in AD. We examined the impact of hippocampal PKMζ overexpression on AD-related memory impairment in rats. Oligomeric form of Aβ (oAβ) or vehicle was bilaterally microinjected into the dorsal hippocampus of male Wistar rats under stereotaxic surgery. One week later, 2 μl of lentiviral vector (108 T.U. / ml.) encoding PKMζ genome was microinjected into the dorsal hippocampus. Seven days... 

Shrimp aquaculture is one of the fastest-growing food production sectors in the world, due to its economic importance and ability to meet the protein needs of a growing population. However, bacterial and fungal infection has caused significant problems in the shrimp sector which instigated enormous economic loss for the main producer countries. Probiotic feed additives can enhance the gut health benefits and immune status of shrimp, thus boosting the growth, production efficacy, and disease resistance. Thereafter, the effects of different levels of dietary probiotic, Pediococcus acidilactici (PA), on growth performance, feed consumption, immunological response, antioxidant activities, and... 

This paper introduces a groundbreaking classification model called the Controllable Ensemble Transformer and CNN (CETC) for the analysis of medical images. The CETC model combines the powerful capabilities of convolutional neural networks (CNNs) and transformers to effectively capture both high and low frequency features present in medical images. The model architecture comprises three main components: a transformer classification block (TCB), a transposed-convolutional decoder block (TDB), and a convolutional encoder block (CEB). The CEB is responsible for capturing multi-local features at different scales and draws upon components from VGGNet, ResNet, and MobileNet as backbones. By... 

In this paper the element free Galerkin method (EFGM) has been extended to be used in the elastoplastic stress analysis. The developed method has been examined in planar stress analysis around the tip of a crack and in its opening mode of loading. To do this, at the first step by using the incremental relations of plastic deformation a system of elastoplastic EFGM equations has been derived. Since the obtained relations are nonlinear, a nonlinear solution technique has been chosen. To examine the validity of this technique, stress fields in two different plates with and without a crack have been calculated and the results have been compared with other similar analytical works in the... 

Cometary activity is a manifestation of sublimation-driven processes at the surface of nuclei. However, cometary outbursts may arise from other processes that are not necessarily driven by volatiles. In order to fully understand nuclear surfaces and their evolution, we must identify the causes of cometary outbursts. In that context, we present a study of mini-outbursts of comet 46P/Wirtanen. Six events are found in our long-term lightcurve of the comet around its perihelion passage in 2018. The apparent strengths range from -0.2 to -1.6 mag in a 5″ radius aperture and correspond to dust masses between ∼104 and 106 kg, but with large uncertainties due to the unknown grain size distributions.... 

Background: cervical cancer is one of the most common malignancies in women worldwide and its management remains challenging and complex. As Cytochrome4Z1 (CYP4Z1) is overex-pressed in many tumours, its expression in cervical cancer is unknown. Therefore, the present study aimed to evaluate CYP4Z1 expression in cervical cancers. Methods: CYP4Z1 expression was immunohistochemically assessed in 100 cases of cervical cancers along with ten normal cervix tissues, and the enzyme’s relationship to several clinicopathological features and survival was explored. Results: CYP4Z1 was strongly expressed in 55% of cervical cancer patients. Normal cervix samples were negative for CYP4Z1 expression....