Experimental study on energy consumption of computer numerical control machine tools

Machining processes are responsible for substantial environmental impacts due to their great energy consumption. Accurately characterizing the energy consumption of machining processes is a starting point to increase manufacturing energy efficiency and reduce their associated environmental impacts. The energy calculation of machining processes depends on the availability of energy supply data of machine tools. However, the energy supply can vary greatly among different types of machine tools so that it is difficult to obtain the energy data theoretically. The aim of this research was to investigate the energy characteristics and obtain the power models of computer numerical control (CNC) machine tools through an experimental study. Four CNC lathes, two CNC milling machines and one machining center were selected for experiments. Power consumption of non-cutting motions and material removal was measured and compared for the selected machine tools. Here, non-cutting motions include standby, cutting fluid spraying, spindle rotation and feeding operations of machine tools. Material removal includes turning and milling. Results show that the power consumption of non-cutting motions and milling is dependent on machine tools while the power consumption of turning is almost independent from the machine tools. The results imply that the energy saving potential of machining processes is tremendous

An investigation into reducing the spindle acceleration energy consumption of machine tools

Machine tools are widely used in the manufacturing industry, and consume large amount of energy. Spindle acceleration appears frequently while machine tools are working. It produces power peak which is highly energy intensive. As a result, a considerable amount of energy is consumed by this acceleration during the use phase of machine tools. However, there is still a lack of understanding of the energy consumption of spindle acceleration. Therefore, this research aims to model the spindle acceleration energy consumption of computer numerical control (CNC) lathes, and to investigate potential approaches to reduce this part of consumption. The proposed model is based on the principle of spindle motor control and includes the calculation of moment of inertia for spindle drive system. Experiments are carried out based on a CNC lathe to validate the proposed model. The approaches for reducing the spindle acceleration energy consumption were developed. On the machine level, the approaches include avoiding unnecessary stopping and restarting of the spindle, shortening the acceleration time, lightweight design, proper use and maintenance of the spindle. On the system level, a machine tool selection criterion is developed for energy saving. Results show that the energy can be reduced by 10.6% to more than 50% using these approaches, most of which are practical and easy to implement

An investigation into methods for predicting material removal energy consumption in turning

The wide use of machining processes has imposed a large pressure on environment due to energy consumption and related carbon emissions. The total power required in machining include power consumed by the machine before it starts cutting and power consumed to remove material from workpiece. Accurate prediction of energy consumption in machining is the basis for energy reduction. This paper investigates the prediction accuracy of the material removal power in turning processes, which could vary a lot due to different methods used for prediction. Three methods, namely the specific energy based method, cutting force based method and exponential function based method are considered together with model coefficients obtained from literature and experiments. The methods have been applied to a cylindrical turning of three types of workpiece materials (carbon steel, aluminum and ductile iron). Methods with model coefficients obtained from experiments could achieve a higher prediction accuracy than those from literature, which can be explained by the inability of the coefficients from literature to match the specific machining conditions. When the coefficients are obtained from literature, the prediction accuracy is largely dependent on the sources of coefficients and there is no definitive dominance of one approach over another. With model coefficients from experiments, the cutting force based model achieves the best accuracy, followed by the exponential function based method and specific energy based method. Furthermore, the power prediction methods can be used in process design stage to support energy consumption reduction of a machining process

Dumbbell shaped craniorbital cavernous hemangioma.

BACKGROUND: Cavernous hemangioma of the orbit is a benign tumor mostly located behind the eye globe, but it rarely spread into the brain, which is called cerebral cavernous malformation as well, the lesion in the brain is irregular and enlarged blood. Here we report one particular case of craniorbital cavernous hemangioma. CASE PRESENTATION: A 53-year-old woman presented with exophthalmos of the right eye and reduced vision. Computerized tomographical (CT) scan showed osteolytic honeycomb radial changes of the outer plate of the skull. A magnetic resonance imaging (MRI) scan was performed to obtain further details. T1-weighted (T1W) imaging showed slightly low signal mixed with small patchy high signal. T2-weighted (T2W) imaging showed uneven high signal. There was obvious enhancement in the middle and no enhancement in the peripheral bars. A surgically manage was performed using a left frontotemporal approach, the tumor excised fully, and the histopathology results revealed a cavernous hemangioma. The patient recovered well in the follow-up. Post-operative CT scan identified the lesion was successfully resected, MRI scan also showed full resection and enhanced signal from the presence of fat. CONCLUSIONS: Craniorbital cavernous hemangioma is uncommon, however within the cranium, they can lead to numerous complications particularly if affecting the visual apparatus. it could be diagnosed by imaging, which CT scan shows osteolytic honeycomb radial changes of the outer plate of the skull, T1W imaging shows slightly low signal mixed with small patchy high signal, T2W imaging shows uneven high signal, it is obvious enhancement in the middle and no enhancement in the peripheral bars. The surgically manage is the ideally treatment when there are some symptoms

Mechanism and Treatment Related to Oxidative Stress in Neonatal Hypoxic-Ischemic Encephalopathy

Hypoxic ischemic encephalopathy (HIE) is a type of neonatal brain injury, which occurs due to lack of supply and oxygen deprivation to the brain. It is associated with a high morbidity and mortality rate. There are several therapeutic strategies that can be used to improve outcomes in patients with HIE. These include cell therapies such as marrow mesenchymal stem cells (MSCs) and umbilical cord blood stem cells (UCBCs), which are being incorporated into the new protocols for the prevention of ischemic brain damage. The focus of this review is to discuss the mechanism of oxidative stress in HIE and summarize the current available treatments for HIE. We hope that a better understanding of the relationship between oxidative stress and HIE will provide new insights on the potential therapy of this devastating condition

Adapting a generic tuberculosis control operational guideline and scaling it up in China: a qualitative case study

<p>Abstract</p> <p>Background</p> <p>The TB operational guideline (the <it>deskguide</it>) is a detailed action guide for county TB doctors aiming to improve the quality of DOTS, while the China national TB policy guide is a guide to TB control that is comprehensive but lacks operational usability for frontline TB doctors. This study reports the process of deskguide adaptation, its scale-up and lessons learnt for policy implications.</p> <p>Methods</p> <p>The deskguide was translated, reviewed, and revised in a working group process. Details of the eight adaptation steps are reported here. An operational study was embedded in the adaptation process. Two comparable prefectures were chosen as pilot and control sites in each of two participating provinces. In the pilot sites, the deskguide was used with the national policy guide in routine in-service training and supervisory trips; while in the control sites, only the national policy guide was used. In-depth interviews and focus groups were conducted with 16 county TB doctors, 16 township doctors, 17 village doctors, 63 TB patients and 57 patient family members. Following piloting, the deskguide was incorporated into the national TB guidelines for county TB dispensary use.</p> <p>Results</p> <p>Qualitative research identified that the deskguide was useful in the daily practice of county TB doctors. Patients in the pilot sites had a better knowledge of TB and better treatment support compared with those in the control sites.</p> <p>Conclusion</p> <p>The adaptation process highlighted a number of general strategies to adapt generic guidelines into country specific ones: 1) local policy-makers and practitioners should have a leading role; 2) a systematic working process should be employed with capable focal persons; and 3) the guideline should be embedded within the current programmes so it is sustainable and replicable for further scale-up.</p

Anatomical and Physiological Plasticity in Leymus chinensis (Poaceae) along Large-Scale Longitudinal Gradient in Northeast China

Although it has been widely accepted that global changes will pose the most important constrains to plant survival and distribution, our knowledge of the adaptive mechanism for plant with large-scale environmental changes (e.g. drought and high temperature) remains limited.An experiment was conducted to examine anatomical and physiological plasticity in Leymus chinensis along a large-scale geographical gradient from 115° to 124°E in northeast China. Ten sites selected for plant sampling at the gradient have approximately theoretical radiation, but differ in precipitation and elevation. The significantly increasing in leaf thickness, leaf mass per area, vessel and vascular diameters, and decreasing in stoma density and stoma index exhibited more obvious xerophil-liked traits for the species from the moist meadow grassland sites in contrast to that from the dry steppe and desert sites. Significant increase in proline and soluble sugar accumulation, K(+)/Na(+) for the species with the increasing of stresses along the gradient showed that osmotic adjustment was enhanced.Obvious xerophytic anatomical traits and stronger osmotic adjustment in stress conditions suggested that the plants have much more anatomical and physiological flexibilities than those in non-stress habitats along the large-scale gradient

Minimising the machining energy consumption of a machine tool by sequencing the features of a part

Increasing energy price and emission reduction requirements are new challenges faced by modernmanufacturers. A cons iderable amount of their energy consumption is attributed to the machining en-ergy consumption of machine tools (MTE), including cutting and non-cutting energy consumption (CEand NCE). The value of MTE is affected by the processing sequence of the features within a specific partbecause both the cutting and non-cutting plans vary based on different feature sequences. This articleaims to understand and characterise the MTE while machining a part. A CE model is developed to bridgethe knowledge gap, and two sub-models for specific energy consumption and actual cutting volume aredeveloped. Then, a single objective optimisation problem, minimising the MTE, is introduced. Twooptimisation approaches, Depth-First Search (DFS) and Genetic Algorithm (GA), are employed togenerate the optimal processing sequence. A case study is conducted, where five parts with 11e15features are processed on a machining centre. By comparing the experiment results of the two algo-rithms, GA is recommended for the MTE model. The accuracy of our model achieved 96.25%. 14.13% and14.00% MTE can be saved using DFS and GA, respectively. Moreover, the case study demonstrated a20.69% machining time reduction