All prompts are created equal,but some prompts are more equal than others

Scores assigned to college placement essays by a computer program (PEG) showed high agreement with the evaluations of human readers (r =.82). Further, both types of graders tended to assign higher or lower scores to essays written about particular topics. Content analyses by a second program (MCCA) indicated that themes in essays varied in terms of emphasis on "analytic," "emotional," or "practical" dimensions. Human and machine readers tended to give higher scores for analytic and practical themes, and lower scores for those involving emotion. The ranks of mean prompt-related grades were concordant with the ranks of mean analytic and practical content across topics. Such findings call for the refined standardization of prompts for future testing, and the need for care in the evaluation of existing essays.     

Not all areas are equal: analysis of citations in information security research

Scientometrics - The understanding of the inner workings of a research community is essential to evaluate the impact of an author as well as to decide where and how to publish results. One of the...     

Calculation of shape factors by means of the equal energy partitioning method and its modification

Abstract

The present study develops a method called the energy equal partitioning method. This method divides all the solid angles of a radiating source properly so that the energy carried by the beams within each small range of the solid angle are equal. The fraction of energy beams arriving at the wall surface is then examined to obtain the shape factor. This method can be efficiently applied to complex geometries. Comparing the rate of convergence and the cost of computing time shows that the shape factor obtained by the present method is better than that obtained by the Monte Carlo method. The influence of the geometric configuration on the accuracy of the shape factor is also investigated. The shape factor obtained by this method is modified by using the original shape factor as a weighting factor. An iteration procedure is developed. The resulting shape factors satisfy the reciprocity law and energy conservation law and the degree of closeness to the exact shape factors is found to be better.     

Stored energy and recrystallization temperature in high purity copper after equal channel angular pressing

Equal channel angular pressing (ECAP) was conducted at room temperature to impose high strain into high purity copper. Differential Scanning Calorimeter (DSC) was used to estimate the stored energy from ECAP and recrystallization temperature. It was found that the stored energy increases upon ECAP processing until a peak is reached at 12 passes of ECAP, and a slight decrease in stored energy was observed at higher ECAP passes. The recrystallization temperature decreases upon the increase of the stored energy up to ~50 J/mol, and reaches a stable valve of ~210 °C. Partial annealing of an ECAP processed (8 passes) sample by heating to ~185 °C at a heating rate of 20 °C/min released the stored energy from ~55 to ~18 J/mol, without substantial change on the recrystallization temperature of the sample. A two parameters model was used to help calculate stored energy of ultrafine-grained copper after high strain level processing.     

Reducing energy losses when transformers are lightly loaded

A simple new way of reducing the power losses in lightly loaded transformers by up to 80% is presented. The method involves special transformer connections and a switching circuit. The approach works most readily with low voltage transformers, but can be expanded to larger machines. Test data and computer models and are used to support the efficacy of the technique. The idea has been shown to work. A discussion of the method's technical and economic viability is given. As energy supplies are depleted and prices increase, there is a greater need for such a method that reduces energy losses. The advantage of this idea is that it may be employed to all power supply systems at various voltage levels.     

0.1ms脉冲噪声等能量暴露对豚鼠听力损伤的实验观察

本文研究了０．１ｍｓ脉冲噪声等能量暴露对豚鼠听力损伤问题。３７只白色雄性豚鼠，皮层听区埋植慢性电极，分为五个暴露组。各组分别暴露１６３ｄＢ１０发１／１０ｓ，１６３ｄＢ１０发１／９０ｓ，１６３ｄＢ１０发１／０．５ｓ，１６６ｄＢ５发１／９０ｓ和１７２ｄＢ１发的脉冲噪声。暴露２４小时、４８小时和８天后，分别测试各组动物皮层反应阈阈移。结果显示：（１）等能量暴露的五组平均阈移不同，有显著性差异。（２）按３ｄＢ法则，不同峰值和发数组合的脉冲噪声并不完全形成等同程度的听力损伤。（３）在等能量暴露中，重复率是影响听力损伤的重要参数，快和慢重复率暴露比中等重复率听力损伤相对较轻。     

建筑节能认证大有可为

我国<节约能源法>对新建建筑节能、既有建筑节能改造、可再生能源在建筑中的应用、加强政府办公建筑和大型公共建筑的节能运行管理和改造等作出了明确的规定和要求.从整个社会的能耗来看,工业、交通和建筑是最主要的3大能耗领域.数据显示,我国的建筑能耗占社会全部能耗的30%.     

Statistical packing of equal spheres

A computer model which allows us to describe the statistical packing of spherical particles is created. Based on a computer model of statistical packing of particles, research on the distribution of the distance between ‘contacting particles’ was carried out. Bimodality of distribution of the distance between particles is defined. Here the maximal value of a number of pair contacts corresponded to the coordination numbers 3 and 8-10.     

两种不同组合形式的环形网耗能性能的对比分析

通过对单个R0CCO圆环的静力试验和理论分析,推导了圆环等效半径的计算方法。建立了两种组合形式环形网的计算模型：第一种组合形式（模型1）中1个R0CCO圆环与4个R0CCO圆环相连接;第二种组合形式（模型2）中1个R0CCO圆环与6个R0CCO圆环相连接,采用数值分析方法对模型1、2的静动力耗能性能进行了研究。结果表明：①当采用相同的ROCCO圆环组成模型1、2时,模型2中单个ROCCO圆环的耗能能力高于模型1;②当采用相等的材料组成模型1、2时,在相同动能的落石冲击作用下,模型2的变形距离低于模型1,且模型1受到的落石冲击荷载开始时低于模型2,随着落石直径的增大,逐渐高于模型2;③模型1、模型2在落石冲击作用下的极限耗能能力随着落石直径的增大而逐渐增大,且模型1的极限耗能能力开始时高于模型2,当落石直径达到一定程度后,模型2的耗能能力逐渐高于模型1。因此,当实际工程中需要考虑防护系统变形距离时,选择第二种组合形式的环形网可以节约工程造价,而当需要考虑系统极限耗能能力时,可以根据落石特征选择经济合理的环形网结构形式。     

Productivity does not equal usefulness

Scientometrics - For a recent commentary in Nature, Ioannidis et al. (Nature 561(7722):167–169, 2018) searched the Scopus database and identified those “hyperprolific” authors who...     

On paths of two equal collinear cracks

In a previous paper an analysis of the path prediction for a single line crack in sheets of brittle material has been performed. In this work, the analysis is extended to a system of two collinear cracks embedded in an infinite medium subjected to biaxial loading. The interaction between the crack paths is shown. The effects of biaxial loading as well as of crack inclination on the stability of trajectories are pointed out.     

FEM analysis of equal channel angular processes

Much effort has been devoted to the study of the formation of superplastic in aluminum alloys on account of its cost and engineering advantages. From a mechanical point of view, the ability of a crystalline material to undergo superplastic behavior is usually linked to a submicrometer grain size. Equal channel angular extrusion (ECAE) is an innovative technique for developing ultrafine-grained microstructures by introducing a severe plastic deformation in a bulk material with no significant changes in its cross-section. Equally, equal channel angular drawing (ECAD) is an emerging technology that permits more industrial applications than the former. However, the deformations thus obtained are much lower. This work presents a study of the application of the finite elements method to this technique using two common angles of 90 and 120°. Process conditions have been modified in order to analyze the effect of friction between the dies and the billet. Moreover, experimental ECAE and ECAD methods have been carried out using 3103 Al-Mn; 5083 Al-Mg and 1370 aluminum alloys through Routes A and B.     

Exploring a design decision for a cutting stock problem in the steel industry: all design widths are not created equal

International competition is forcing steelmakers to examine carefully all facets of their operations. Continuously casting master slabs, which must be ripped longitudinally to meet customer-specified widths, is one approach that offers significant potential for improving productivity and enhancing quality. An important issue in designing master slab casters is determining the width that the caster should be capable of producing. Using several distributions of customer order widths and an established procedure to combine customer order widths into patterns for ripping master slabs, this paper investigates various master slab widths.

As the master slab width increases, ripping loss (trim loss and other losses) tends to decline. This tendency is punctuated by peaks and valleys in the loss function. Low points in the loss function seem to occur where on the average two, three, four, etc., pieces could be placed across the master slab. It seems that measures of central tendency in the order distribution are good predictors for master slab caster widths that yield low ripping loss.     

十二平均律的理论探讨

以现代声学理论为依据,对朱载靖异径管律的数据和杨荫浏的修正数据,从不同角度在大范围内进行了分析和计算。所得结论表明,若以标准管径值为起点,杨荫浏的管律是不折不扣的十二平均律。从而对长达半个多世纪的律学悬案的最后解决．奠定了理论基础。对今后管律研究和管乐器的制造在理论和实践方面都有参考的价值。     

The role of back-pressure in equal channel angular extrusion

Equal Channel Angular Extrusion (ECAE), developed and patented in Russia by Segal in 1977, has become in the last few years a very popular tool for studying the evolution of microstructure and properties under severe plastic deformation. It is believed that the strain-stress characteristics are uniform in a cross-section of the billet and this uniformity of the stress-strain distribution ensures the uniformity of microstructure and mechanical properties in ECAE processed billet. However, some experimental data such as the fracture of the extruded billet, which is initiated at the inner surface of the sample, has caused doubts about uniformity of stress-strain distribution. This non-uniformity has been proved recently by Finite Element Simulation.This paper reviewed our results from over six years of work using a unique machine for ECAE with computer controlled back-pressure and velocity of the backward punch. Theoretically back-pressure has been introduced in the earlier papers of Segal. However, practically back-pressure has not been widely used or often used in a primitive form of the consequent extruded sample and its role has not been understood.     

Finite element analysis of rotary-die equal channel angular pressing

In this paper, the finite element method (FEM) was applied to analyze the plastic flow and strain hardening behavior of pure copper, subjected to rotary-die equal channel angular pressing (RD-ECAP) up to four passes. The die was rotated 90° counter clockwise between the passes in the simulation. The effective strain distribution and load–stroke curves were investigated. The load was increased with the number of rotary-die equal channel angular pressing passes. The results show that, plastic deformation becomes inhomogeneous with the number of passes due to an end effect, which was not found seriously in conventional equal channel angular pressing (ECAP). Especially, decreasing corner gap with increasing the number of passes was observed and explained by the strain hardening effect.     

等通道转角挤压自增强等规聚丙烯研究

为了研究等通道转角挤压等规聚丙烯的挤压工艺条件、结构与性能之间的关系,采用90°转角模具及挤压路径A、在熔点以下的160℃制备了不同挤压次数的等规聚丙烯样品,利用广角X射线衍射(WAXD)、差示扫描量热分析(DSC)等手段对其结构进行表征.结果表明,随挤压次数增加,等规聚丙烯分子取向明显增加,材料结晶度提高,试样的力学性能提高十分显著,未挤压试样的抗拉强度为17.13 MPa,经过三次挤压后,抗拉强度提高到59.38 MPa.     

你的薪酬=你的价值?

你的枝能是否充分发挥?你的薪酬是否体现出你的价值?本期我们邀请两位专家和我们共同探讨一种新颖的薪酬评价体系——技能工资制。所谓技能工资,简单地说就是指以员工个人所掌握的知识、技术和所具备的能力为基础来进行工资报酬的支付。最近一个时期,这种工资设计的理念受到了来自于理论和实践的普遍关注,成为薪酬领域中的一个热点问题。