Incorporating cycle time uncertainty to improve railcar fleet sizing

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 78-79).This thesis involves railcar fleet sizing strategies with a specific company in the chemical industry. We note that the identity of the company in this report has been disguised, and some portions of the fleets have been omitted to mask their actual sizes. However, all analysis in this thesis was conducted on actual data. In our research, we evaluate the appropriateness of both deterministic and stochastic fleet sizing models for this company. In addition, we propose an economic model that is adapted from a basic inventory management policy that can be applied to fleet sizing in order to arrive at a cost-driven solution. Through our research, we demonstrate that the fleet sizing strategy of this company can be improved by incorporating transit time variability into the fleet sizing model. Additionally, we show that fleet sizes can be reduced by accurately characterizing the distributions of the underlying transit and customer holding time data. Finally, we show the potential value of considering economic factors to arrive at a fleet sizing decision that balances the cost of over-capacity with the cost of an insufficient supply of railcars.by Jay Jagatheesan and Ryan Kilcullen.M.Eng.in Logistic

Development of breathable and liquid/microbes barrier woven surgical gowns for hospital usage

An attempt has been made to develop a breathable woven surgical gown with antimicrobial and liquid repellent properties by finishing with nanoparticles of silver and fluorocarbon using pad-dry-cure method. Box-Behnken design has been used to optimize the coating parameters, i.e. concentrations of nanosilver (NS), nanofluorocarbon (NFC) and binder. The selected coating parameters has decisive influence on the fabric properties, such as air permeability, moisture vapour permeability, antimicrobial and tensile behaviour. The optimum coating parameters such as concentrations of NS, NFC and binder result in improved air permeability and moisture vapour permeability of the fabric for 3 g/L of NS and 40 g/L of NFC. The antibacterial activity of fabric is found to be higher for increased NS concentration and lower for increased NFC. In case of tensile properties of coated fabrics, the increase in NS concentration increases the tensile strength and decreases the bending modulus of fabrics

Electromagnetic shielding behaviour of conductive filler composites and conductive fabrics – A review

In this study, theory of EMI shielding and research conducted on textile fabrics to impart conductivity for attenuating the electromagnetic (EM) radiation by means of different techniques have been reviewed in detail. Shielding of the EM waves can be done by means of reflection, multiple reflection and absorption by the shield. Different metals with their alloys and polymeric materials are initially used as shielding materials with some limitations. However, the recent developments in conductive fabrics and composites replace the conventional shielding materials. The composites with better conductivity and light weight could be a promising barrier material for protecting electronic circuits from the EM radiation and mechanical damage. Materials with high absorption co-efficient could impart shielding effectiveness of 80 dB for the frequency of 18 GHz. This paper mainly focuses on the necessity of conductive textile fabric and composites used as hybrid electromagnetic shields

Cyclic bursting loading on needle-punched nonwovens: Part I – Distention behavior

The present study aims at examining different needle-punched polypropylene nonwovens under different cyclic bursting pressure. Various fabric parameters including mass density, punch density and fibre fineness have been investigated. For the cyclic test, the distension is measured at different cyclic bursting pressures proportionate to the bursting strength of the fabric. Other parameters including the cyclic pressure magnitude, the number of cycles, and the rest time at peak pressure have also been investigated. It has been found that the bursting strength and distension of fabric increase with an increase in mass density, while they show opposite trend with punch density and fibre denier (p < 0.01). The distension value of each sample increases with an increase in the cyclic parameters i.e. number of loading cycle, rest time and pressure peak

A CUSTOMARY ON SHOULDER PAIN POPULATION USING SIMPLE SHOULDER TEST

The purpose of the study is about to identify shoulder pain using a simple shoulder test among the population. BACKGROUND: Shoulder pain is the third most common musculoskeletal complaint encountered in clinical practice. Out of that, rotator cuff tendonitis is one of causes of shoulder pain. Rotator cuff tendonitis is an inflammation of the rotator cuff tendons without a rotator cuff tear. METHODOLOGY: This study is a prevalence study of pre and post test type that was conducted in 500 participants who have shoulder pain are selected and given simple shoulder test questionnaires. The participants with shoulder pain are between the age group of 18 and 60 years and both males and females were included in the study after getting their consent for participations. In these survey the person who is pregnant, who had history of surgery, presence of tumor, cardiac disease, person with cancer, mental disorder, recent fracture and dislocation of joints were excluded from the survey questionnaires. The questionnaires are based on the simple shoulder test, yes or no type with various clinical trials. RESULT : Of the 500 people who completed baseline questionnaires 51% were female and 49% were male. The mean age group is between 18 and 60 years. The result indicates that simple shoulder test questionnaires interpreted 50% of the population with RCT, 26%  with RA, and 24% with DJD. CONCLUSION: The present concludes that simple shoulder test questionnaires are an excellent tool to analyse shoulder pain. Out of 500 patients, 50% of shoulder pain is due to RCT, 26% of pain is due to RA, and 24% is due to DJD

Study of cyclic bursting loading on needle-punched nonwovens: Part II – Change in air permeability and compression behavior

Efforts have been made to investigate the physical properties of needle-punched nonwovens, such as compression and air permeability, before and after the application of cyclic bursting pressure. It is observed that the structural parameters, such as areal density, needling density and fibre fineness, have significant effect on the aforementioned fabric characteristics. More compression is observed in a sample with low mass density. Sample made of coarser fibre shows lower compression as compared to finer fibre samples. The air permeability decreases with increase in mass density. On conducting cyclic bursting test on a sample, the values of air permeability and compression change significantly. The cyclic parameters, such as pressure magnitude and rest time at cyclic peak pressure, cause significant structural changes and reorientation of the fibre during deformation. Increase in pressure and rest time causes increase in compression parameter (α) and air permeability. Nevertheless, at low cyclic pressure level (10% of bursting pressure), the network becomes compact due to fibrous reorientation, and therefore both the values of compression parameter (α) and air permeability show initial drop. On examining the samples made of coarser and finer fibres, the variation is observed in the extent of change in the air permeability

Development of metallic core-spun yarns and hybrid conductive fabrics for electromagnetic shielding applications

346-351Various metallic core-sheath yarns have been prepared and conductive fabrics are woven using sample loom for electromagnetic shielding applications. The core-sheath yarn is prepared using stainless steel and polyester slivers with different proportions of SS fibre content. The conductive fabrics are produced with different warp and weft patterns. The shielding effectiveness (SE) of fabric has been tested in the frequency range from 50 MHz to 1.5 GHz according to ASTM D4935. The test results reveal that the fabric with cell type structures shows better shielding effectiveness (SE) than the plain weave structures. The increase in metal content does not influence the SE of fabric having conductive fibres in one direction. However, fabric having conductive fibres in warp and weft directions shows improved shielding effectiveness. When the grid size is increased, the shielding effectiveness is decreased. It is concluded that the fabric with small grid size and cell type weave structures could provide effective shielding as compared to plain woven fabric in low frequency range

Determinants of dysphagia following stroke

Background: Swallowing is affected following stroke. Many studies focus on various aspects of swallowing difficulties (dysphagia) following stroke. However, there are not many studies on the determinants of dysphagia following stroke. The aim of the present study is to establish the association between various factors with the severity of dysphagia.Methods: After screening for Mann Assessment of Swallowing Ability (MASA),110 patients, post-stroke were selected using consecutive sampling to assess the common risk factors, namely the presence of diabetes mellitus, dyslipidemia, hypertension, alcohol usage and smoking habits. Additionally, other variables such as age, gender, type of lesion, side of lesion, tobacco chewing, speech disorders, arterial dysfunction, lobe involvement and Brunnstrom’s stages, were also evaluated using a structured interview method. c2 (chi-squared) analysis was carried out to find out the association between the selected determinants and severity of dysphagia following stroke.Results: It was found that age and Brunnstrom’s stages are the determinants of dysphagia, as analysis showed a strong association with a p value < 0.001. A marginal association between post-stroke dysphagia and type of lesion with a p value of 0.056 was also observed.Conclusions: Among 15 factors evaluated, age, type of lesion and Brunnstrom’s stages showed a significant association with the severity of dysphagia following stroke. This study advocates early dysphagia management for elderly patients with high Brunnstrom’s grading, for those who are not expected to spontaneously recover following stroke, and for earlier and better community rehabilitation. [Ethiop.J. Health Dev. 2019; 33(3):147-152]Key words: Post-stroke dysphagia, Brunnstrom’s stages, dysphagia risk factors

Awareness and Knowledge of Vertigo among the Adult Population of Selangor, Malaysia

Dizziness and vertigo are common among the adult and elderly population. However, the knowledge & awareness of vertigo and the understanding of the differences between vertigo and dizziness in the adult population is seldom studied. The present study aimed to assess the level of awareness and knowledge of vertigo among the adult population living in Selangor, Malaysia. In addition, the study also focused on the participants’ knowledge of differentiating dizziness and vertigo. This cross-sectional study received responses from 189 participants who were in the age range between 20 and 40 years among which 152 participants' responses met the inclusion criteria. A self-developed validated online questionnaire was used as a study tool to understand the awareness and knowledge of vertigo among the participants. Data analysis was conducted using SPSS (version 28) to obtain frequency and percentages. The results of the present study showed that 57.9% of participants had an average level of awareness of vertigo. Further, 55.3% disagreed that vertigo is the same as dizziness however only 6.6% of the participants were exactly able to identify the differences between vertigo and dizziness. The present study concludes an average level of awareness and knowledge of vertigo among most young adults of Selangor, Malaysia. However, the ability to differentiate vertigo from dizziness was very low among the participants, demonstrating a gap in their knowledge of vertigo. Hence, education about vertigo among the public must be ameliorated. Further studies are required on different age groups and within the other states of Malaysia